checking an alternator?

[trueblue]

how do you check an alternator is working properly on a Yamaha 130 hp 2 stroke?

It seems to be charging allright, but I am seeing some erratic voltage readings on the yammy instruments, floating between 14.6 and 15.2 Volts.

I have never noticed erratic voltage like that, and my battery is reading 13 volts which is higher than I have usually seen before.

I changed batteries to see if that was the problem, but all exactly the same on a different battery

cheers

Mick

[FNQCairns]

What does your battery read after the surface charge is gone? This can be a more representative measure of battery state, my 2 stroke yam gives more or less the same voltage outputs as your seeing, the bigger the battery the lower the charge voltage, something i have noticed over the years, dont really know why.

My smart charger will charge at almost 15v for a period with all charging done above 13.5 or there about's.

On the surface all seems typically fine, doesn't mean I am right though.

[trueblue]

I thought that the charging voltage used to drop after a period, but I can't be sure on that.

going to get the primary battery tested to see if it has any issues.

Main problem is a random and intermittent engine alarm throwing the engine into limp mode, without any warnings showing (like oil level, temp etc) I'm trying to isolate and find this problem, but its very difficult when it only seems to happen occasionally while under way out on the water with no indications on the instruments as to what the problem might be

cheers

Mick

[honda900]

Mick,

your sounder / GPS may have an overlay option to allow you to put the voltage on the display, to confirm what you see on the yam gauges, dont know that its going to help you tho.

Regards
Honda.

[trueblue]

yeah, I looked at the fish finder voltage display while stopped and it said 13v, higher than ever before. Never occurred to look at that while running though.

just got the battery tested and it is tickety boo so not that.

maybe it has a problem with the rectifier diodes and is overcharging?

[finga]

If there is a problem it would more then likely be in the regulation side of things.
If your motor has gone into limp mode does it record a fault?

What test gear have you got?

[trueblue]

I don't think it would record anything, its a 98 yammy 2 stroke. it would be great though if there was something there to tell me what the fault was.

I don't have any electrical test gear at all

cheers

Mick

[FNQCairns]

Being that old could it be temperature or oil supply??. i suppose a short could cause electronic havoc..i dunno the yamaha's but they are pretty much all the same. Your volts seem fine to me, mine does the same and just like all the engines before it 15v doesn't raise much of an eyebrow if read from a genuine gauge, 15+ read by multimeter in real-time and i would get curious, 16 and defiantly worth a look-see.

Have you investigated temperature?, you might be experiencing blocked popets or thermostat or the dreaded exhaust plate/head blockages.

[Midnight]

Mick,
The charge voltage as indicated on your guages and sounder will increase in Volts from idle up to an Rpm where the Gennie will produce the design output voltage and amps. Most outboard alternators don't produce the design charge output until you get a fair way into the revs. The newer ones are improved in this department to run all the usual Yankee accesories.

Do you run a VSR between your batteries? I can't remember?

Damn electrics, I hate em!>:( Give me an oil leak to deal with any day haha

Cheers,
Myles

[oldboot]

Fellas, fellas...... buy a boat... then buy a multimeter...I know a few of the poster definitely have them.

You can get a half decent one for little more than $20.....and that will be more accurate and easier to use than Half the multimeters I have owned or been issued with in the past.

If you go to jaycar..they have great little book that will tell you how to use it.

Then things get a whole lot easier........

also remember you won't get the same reading on most boat charging systems that you will get on automibiles.

car alternators will give a pretty constant 13.8 volts ( some fancy ones all betts are off).
Car alternators will put out at least 40 amps and may be up to 120 amps

Outboard motor charging systems are pretty crude in comparison.... voltage regulation is nowhere near as good and the output can be as low as 8 amps( small motors even less) and rarely more than 20 amps

Having the manual for that motor is a realy good thing because it will tell you what yu should see.

now....indeed the output of outboard charging circuits is very much dependednt on RPM and the size and condition of the battery... ....(most specify a battery arround a particular size)

The maximum charging voltage may be as high as 15 volts..... but because the output of these circuits is so pissy it may take a while to get there if the battery is low on charge or larger that specified.

as to the current problem.

The first thing I would be doing is checking the quality of all your main battery connections.....problems here are very common.

a reading between 14.6 and 15.2 would not worry me, if it was on a typical analogue dash guage you probaly would not see it as a variation

One real problem is iff the battery connections are poor and the battery is partly disconnecting....... not good this can blow up your chaging circuit.

make sure those connections are good, clean and firm

There will be specified tests in the manual... but the following will give a pretty good idea.

read the voltage on the battery after it has been left to rest for a few hours....It should be arround 12.5 volts ish.

leave the multi meter connected or hold the probes while someone else starts the motor.......you should see the voltage drop during cranking (if the meter is fast enough to follow).

once the motor starts the voltage should recover and steadily increase well past 13 volts.... both my evenrude and the bro'inlaws merc will reach arround 15 volts

this agrees with the manuals.

cheers

[trueblue]

All the electric cables are new, terminals clean, lugs and connections clean and tight. I've had that problem previously a while ago.

what is very weird was the floating voltages while at a steady cruise.

only one battery connected at the moment.

[trueblue]

I don't think it is temperature because the temp alarm didn't show on the gauge, and it had no pattern to it. I would have thought if it was temp it would heat up consistently over a set period of time and set of an alarm which it did not do.

this is a totally random engine alarm

[mobsta]

I have a 20HP Honday 4 stroke. I am about to connect a deep cycle battery to the boat but apon testing the 12V 6A charging connector from the engine i get no voltage. I checked the fuse, all fine. I checked the cables that come directly from the alternator and i still get no voltage. I then thought that the engine would have to be in gear to get the alternator to generate, and still no volts. Is the alternator rooted? I am thinking it is. Any thoughts?

[mobsta]

I have a 20HP Honda 4 stroke. I am about to connect a deep cycle battery to the boat but apon testing the 12V 6A charging connector from the engine i get no voltage. I checked the fuse, all fine. I checked the cables that come directly from the alternator and i still get no voltage. I then thought that the engine would have to be in gear to get the alternator to generate, and still no volts. Is the alternator rooted? I am thinking it is. Any thoughts?

[frankgrimes]

Cant help you mate, but start a new thread on your problem....more chance that people will respond.

Mick

[MudRiverDan]

The maximum charging voltage may be as high as 15 volts..... but because the output of these circuits is so pissy it may take a while to get there if the battery is low on charge or larger that specified.


a reading between 14.6 and 15.2 would not worry me, if it was on a typical analogue dash guage you probaly would not see it as a variation


Agree.
Only done some backyard car mechanics but for a 12 Volt system 14.6 - 15.2 is charging well.
Your battery , let it rest for 15 minutes then check it, Ideally should read between 12.3 - 13.

Charging does depend on a regulator, this 'regulates' the rate of charging, not sure about boats any further than this.

[ozscott]

Your regulator might be on the way out. 14 odd is usual for a v4'yammy. My 94 v4 115 just started charging 17.3 at revs and reg replaced at back to 14 volts.

The limp alarm may well be heat. What checks have you done? The ya
Oil injection is very reliable. Cheers

[trueblue]

old forgotten about thread...

all resolved now

it turned out to be a temperature alarm, just barely able to set it off then and went back into normal range almost immediately

got sorted by a good clean out (heads off and water galleries cleaned out)

[oldboot]

Mobsta mate...has this motor ever had a battery connecte to it in the past?

If not it is pobaly not fitted with a rectifier.

If it has been fitted with a battery and it has now been run without a battery connected the rectifier is probably stuffed.

In these small motots it is not an alternator, it is magneto.....there is a very big difference.

A magneto will generate huge volatges when run unloaded like hundreds of volts..this will snot the diodes or regulator.

so exactly what is the situation and what is there.

cheers

[Fed]

Magnetos fire spark plugs they don't charge batteries.
You can run outboards without a battery just don't disconnect a battery while the outboard is running.

[cormorant]

Not sure with a outboard alternator but some of the new vehicle ones will not output unless they can feel a voltage from a battery.

Be warned a deep cycle depending on type may never fully charge and is not what your outboard was designed to charge.

[finga]

Mobsta mate...has this motor ever had a battery connecte to it in the past?

If not it is pobaly not fitted with a rectifier.

If it has been fitted with a battery and it has now been run without a battery connected the rectifier is probably stuffed.

In these small motots it is not an alternator, it is magneto.....there is a very big difference.

A magneto will generate huge volatges when run unloaded like hundreds of volts..this will snot the diodes or regulator.

so exactly what is the situation and what is there.

cheers


Magnetos fire spark plugs they don't charge batteries.
You can run outboards without a battery just don't disconnect a battery while the outboard is running.

Oh goodo then.
More controversy.

I might even learn something here :)

[oldboot]

Magnetos fire spark plugs they don't charge batteries.
You can run outboards without a battery just don't disconnect a battery while the outboard is running.

RUBBISH
A magneto is any type of electricity generating device where a rotating permanent magnet is spun past a stationary coil to generate electricity.

They can take many similar forms.......your outboard ( unless it is a large one) will have a magneto that usually has two coils, one high voltage coil to generate spark and another low voltage coil that may be used to generate a charging current The tacho usually takes pulses from the charging coil.....engine goes and tacho does not the charging system may be stuffed

A magneto has no means of active regulation within its self, magnetos are also relativly high impedance devices ( they have significant internal resistance)..as such run without a load they can generate much higher voltages than their normal operating voltage.
Any regulation is either electronic and external to the magneto, or it is accomplished by playing the internal resistance against a designed load.

You can varify this by looking at any decent outboard motor manual, althout it may not have all the detail.

Many early airoplanes had wind driven magnetos to run the radio and lights.....

An alternator is a device where a electricaly energised windings are spun past a stationary field or fields to produce electricity......the output voltage is regulated by varying the field current.......this is what produces electricity for most of our homes and what you have in your car.......mostly only very large outboard motors have true alternators.

Now here is the important difference and one that costs outboard owners $$$$ every year.

If you run an outboard motor with a working charging circuit, without a battery or at least a sufficient load you have a very real probability ( not posibility, not risk, near certain probability) that the diodes in the rectifier or the semiconductors in the regulator will be blown due to over voltage.....This is a very common occurance.

An alternator on the other hand, ( in automotive we use non self exciting alternators), if you can get the motor started, an alternator will not properly function without the battery it needs to make the field.....even if the alternator can self excite from residual magnetism it is unlikly to generate high voltages, and has a pretty damn good chance of comming out of the whole thing unscathed...people have driven cars hunderds of Km with torch batteries or other small or near dead batteries powering only the coil, with the remainder of the electrics disconnected.....and just stick a good battery in and away.
Not a god idea to run you car alternator with no battery, but it is not near certain death for the alternator.

If you have to or want to run your outboard without a battery and there is a complete and working charging system.....you are best advised to disconnect the MAGNETO wires from the rectifier or regulator.......most usually these are the yellow wires comming from under the flywheel....many outboard manuals will detain how to do this

Now back to the deep cycle battery and the non working charging circuit.......as I have detailed before....with our uotboard charging systems, they are designed arround a battery of a certain size....there is quite a bit of latitude, but if you go silly either way you can have a problem.
I doubt that the battery being deep cycle in its self will be a problem, but if you have a very large battery connected to a small charging system..... it wont reach charging voltage and wont charge it.
If the battery is way too small, the battery will not provide sufficient load and it will overcharge.
The above two points are particularly true of charging systems that have only a rectifier.....those with a regulator will suffer less on bothe counts.

even if the small charging system reached sufficient voltage to put in some charge..simple maths will tell you it aint going to do much to fully charge a big battery.
6 amps into a 120 AH battery and you be taking 10 to 12 hours and then some high RPM running the fully charge from half flat

cheers
Remember too that these magneto charging systems, are very inefficient and produce very small amounts of charge compered to what we are used to from an alternator in a car, truck or tractor.

[Fed]

Well I disagree oldboot.

[finga]

Oh, come on now.
You can do better then that Fed.

So apparently.... A magneto is any type of electricity generating device where a rotating permanent magnet is spun past a stationary coil to generate electricity.
And apparently an alternator is a device where a electricaly energised windings are spun past a stationary field or fields to produce electricity......the output voltage is regulated by varying the field current.......this is what produces electricity for most of our homes and what you have in your car.......mostly only very large outboard motors have true alternators.
Besides the way one of the above doesn't really correspond to my learnings and the other is very vague and not the whole story but I'm not going to butt in here for a bit.
So what is your full definition of a magneto, an alternator, a generator and a dynamo Old Boot?
I love working my brain by bringing back all the old stuff I've learnt. It's going to stop me from getting alzheimer's I reckon and more fun then doing a crossword:)

[ozscott]

Come on Finga - just put those of us who dont really know and would like to know (like me who has always thought a Magneto charges a battery in a boat using regulated current - hence why when my regulator blew my Yammy was charging at a battery frying 17.3v - but doesnt charge with much amperage unlike a decent alternator).

I know you are having fun poking at stick at OB (and that is fun..no offence OB but it is) but I would like to know... I can search the net all day but I wont know the reality until an electrician who knows boats tells me.

Cheers

[Fed]

Oh, come on now.
You can do better then that Fed.
Mate I'm not going to argue the magneto vs alternator point, I couldn't be bothered.
As far as I'm concerned the common usage of the words is,... magnetos make the sparks & alternators charge the batteries.
It's like calling a fuse a circuit breaker, well fuses do break circuits you know. LOL!

[finga]

It's like calling a fuse a circuit breaker, well fuses do break circuits you know. LOL!
So is a pair of pliers sometimes :(

[oldboot]

Come on chaps this is 1st year electrical theory.

As for common use..who's common use.
There are a great many situations where the ignorant common use by those who don't want to know the difference causes a failure in understanding, failures that cost people.

There are a great many cases where the common use term is plain wrong and gives and exactly wrong idea of the way an item works.

There are a lot of terms that have become generalised, particularly in trade areas where they no longer mean anything becuase those specific items are no longer encountered.

For instance it would be almost unknown for a houshold or industrial sparkie to have anything to do with an electrical generating device that was not an alternator and most likley only one specific type (medium sized and self exciting).
So to them, it matters little what you call it....call it a spinning round thing...and apart from the stupid looks from others it will make little difference.

A generator could be anything that makes electricity from motion, an alternator obvioulsy makes alternating current.....The word "Dynamo" is hardly used these days and anybody using the word magneto in relation to grid connected electric's is using it from ignorance.

BUT..for those who want to know.

In automotive, motorcycle and marine electrics the terms used are clear in their meaning, and refeer to specific types of components.

A Dynamo, again is a word hardly used these days and mostly will only be seen in books prior to the 70's...."I had a 'dynamo' on my push bike"..... many vintage car manuals refeered to the generator as a Dynamo......forget it hardly used these days.

NOW
In auto electrics and thus small craft marine electric's.

A "Generator" is a device that directly produces a DC output, as found in cars prior to the 70's..most usually it is a device that rotates a comutated (changing) spinning field winding past a stationary winding to produce a rough DC output.....output voltage is regulated by varying field current....a generator does not have a rectifier following the windings.

By the 70's most vehicles came fitted with "Alternators", these devices operate by rotating a spinning constant ( more or less) field winding past stationary winding/s and produce Alternating Current which is then rectified to produce DC, the output voltage is regulated by varying the field current.
Importantly alternators produce a pretty clean and symetrical sinewave.....in practice automotive alternators are 3 phase devices producing 3 sincronised but phase seperated sinewave outputs...when rectified and added together this produces a pretty danm smooth, clean DC output.

In general "alternators" are physically smaller, lighter, far more efficient and work well over a wider range of RPM than "generators"

As used with engines a "Magneto" is a very specific thing and differs greatly in both use and construction to the above.

Most importantly it is a permanent magnet device.
Mostly the permanent magnets are part of the flywheel of the motor and the windings are fitted behind the flywheel.

Quite often the charging and the ignition windings have common portions or are continuations of each other, although some times the windings are phisically and electricaly seperate parts of the same device and working by the same principle.

NOW here is where some people fail to understand......you will not get a good, hot, clean reliably timed ignition spark from a magneto winding alone....most magneto ignitions have some sort of interupter circuit (a set of points in some cases) to both correctly time the ignition and to intensify the spark voltage.......the magneto coil in this case opertaes similar to a coil in a car using the back EMF to produce a high voltage.

Many of the modern ( ish) outboards use some sort of seperate electronic ignition module to make and time the spark, the ignition magneto coil simply being a source of supply, there may actually be a more or less conventional coil involved.

The magneto charging circuit as mentioned before operates by the same principles as the ignition circuit, but it is run on a constant basis with no breaker points device.

The important things to understand and why we must darw attention to the difference is that "Magneto charging circuits" have some very specific limitations and effects.
It must be understood that a "Magneto" is one of the oldest, crudest, and least efficeint electricity generating devices we have.

It has no means within it self to regulate its output, the output voltage and its ability to deliver current varies with RPM. It may do very little in the way of charging at low RPM.

Depending on how the windings and magnets are arranged, the AC output from a magneto can be quite dirty, in that it may not be a nice smooth sine wave, even after rectification it will not produce the nice smooth DC that an 3 phase automotive alternator will.

The " Magneto" has an inherantly high internal resistance, so as current draw is increased voltage tends to drop.
This internal resistance also therefore impacts on voltage regulation.

So as load decreases voltage increases....with no load the voltage increases by a large amounts.
As RPM increases, voltage increases.....this is the combination that blows regulator and diode packs when motors are run with out load or a battery.

another limitation is how regulation is achieved.

Many of the smaller motors only have a diode pack......something resembling redulation is achieved by selecting battery size and playing that aginst the internal resistance....the battery is big enough to load the coil down and cop the charge but not so big that the voltage drops to the point that little or no charging occurs......sound crude..hell yeh, but it works as long as you use a battery close to the right size.

Most small motors that have small charging systems and are not electric start, do not come fitted with the rectifier pack, for two reasons...one, price and future accessory sale, and two...if the motor is started without a battery connected the diode pack will almost certainly blow

In the case of regulated systems, the regulator has to be loss bassed...the regulator disipates all excess electrical energy..this means that the size of the regulators and the magnetos is limited.
If the battery is fully charged and there is no accessory load, the regulator has to be able to disipate the full output of the magneto.

This differs to automotive generators and alternators that regulate by varying a relativly small field current....thus they do not generate excess power to start with.

Because of the above, magneto charging circuits are generally very low power in comparison to alternators.....20 pluss amps is a large magneto charging circuit..some outboads may be as small as 3 or 4 amps, some respectable sized outboards may come with quite small charging outputs....my 60 evenrude came with the big 18 amp circuit but it may have been fitted with as small as 6 amps.

A 40 amp alternator in a car is pretty small, many modern cars have 80, 100, 120 amp alternators.
Remember an alternaotor preforms consistently over a wide rev range.

It is these differences that trap people time and time again.

This is why it is important to call the generating systems by their correct names, because the names come with expectations.

A magneto charging system is a crude, pissy little, badly behaved charging system that may cost you $300 if your battery is disconnected with the motor running..

An alternator charging system is expected to be much higher output and far better behaved.

I hope this makes sence to those who want to know.

cheers

[Fed]

A magneto charging system is a crude, pissy little, badly behaved charging system that may cost you $300 if your battery is disconnected with the motor running..
Hedging your bets are you? ::):P

Someone stick a fork in him I think he's done.:D

[finga]

Two lines each....what is your definition of an alternator, a generator, a dynamo and a magneto Old Boot?
I couldn't be bothered to read that mumbo jumbo I'm afraid. I might later when I have more time but for now....

There was one thing that did not quite make sense when I rushed through it though
It must be understood that a "Magneto" is one of the oldest, crudest, and least efficeint electricity generating devices we have.
So why aren't magneto's called generators??

I'm off for tea.

PS: We dealt a lot with charging thingo's in my TAFE courses. Wasn't just 1st year that's for sure.
Is a 50MVA alternator a small round spinny thing?

[ozscott]

Poke poke...

[cormorant]

Geeze a dynamo is a washing detergent - everyone knows that ;D. You guys should get out more , less chatting up the check out chick , moving that little advertising triangle divider thingo and cruise the isles!! The other 2 are probably in isle 17 but I never go there! :o That is for serious shoppers only

[finga]

Two lines each....what is your definition of an alternator, a generator, a dynamo and a magneto Old Boot?
I couldn't be bothered to read that mumbo jumbo I'm afraid. I might later when I have more time but for now....

There was one thing that did not quite make sense when I rushed through it though
It must be understood that a "Magneto" is one of the oldest, crudest, and least efficeint electricity generating devices we have.
So why aren't magneto's called generators??

I'm off for tea.

PS: We dealt a lot with charging thingo's in my TAFE courses. Wasn't just 1st year that's for sure.
Is a 50MVA alternator a small round spinny thing?
bump.
Nearly forgot about this until I saw Oldboot posting in another thread

[oldboot]

If you can't be bothered reading and understanding my post in its entirety, that gives a full and adequate explanation of the terams I cant be bothered giving you a simplified explanation.

cheers

[finga]

RUBBISH
A magneto is any type of electricity generating device where a rotating permanent magnet is spun past a stationary coil to generate electricity.

An alternator is a device where a electricaly energised windings are spun past a stationary field or fields to produce electricity......the output voltage is regulated by varying the field current.......this is what produces electricity for most of our homes and what you have in your car.......mostly only very large outboard motors have true alternators.

An alternator on the other hand, ( in automotive we use non self exciting alternators), if you can get the motor started, an alternator will not properly function without the battery it needs to make the field.....even if the alternator can self excite from residual magnetism it is unlikly to generate high voltages, and has a pretty damn good chance of comming out of the whole thing unscathed...


cheers
Remember too that these magneto charging systems, are very inefficient and produce very small amounts of charge compered to what we are used to from an alternator in a car, truck or tractor.
Well I disagree as well.

A generator is anything that can change one form of energy into another.

In this instance it is generally accepted that we're referring to a mechanical force been made into electrical energy.
This mechanical energy that is converted to an electrical energy can be broken down into two main sub categories. AC and DC been generated via the process of induction. Induction basically means a form of magnetic field is there somewhere

Anything that generates electricity in an AC wave form is called and Alternator (because the wave form alternates above and below the zero reference point)

Anything that produces a DC output via induction is called a Dynamo. It is generally accepted that the wave form from a dynamo is not a pure DC output.

There are other methods of DC generation like solar and chemical electrical generation but they don't require a magnet somewhere so they're in another classification I won't go into here as we're just talking about the conversion of mechanical force to electrical energy.

Now to the magneto bit.
A magneto is any type of electricity generating device where a rotating permanent magnet is spun past a stationary coil to generate electricity.
Rubbish. A magneto is a specific type of alternator as it's output is AC.
A magneto is a type of alternator specifically designed to give an output of a substantially high output voltage to enable spark to jump across two contacts to cause an internal combustion engine to run.
The real proof of this meaning is either to do a google for magneto or, better still, is to go into an outboard shop, go to the spare parts counter and ask for a magneto for a 1978 20hp Evinrude and see what you get.
Hint. It won't be the charging coil. It'll always be the bit that gives the spark plugs the spark.

Self excitation, various types of magnetism and various regulation methods have nothing to do with the general terms for the various types of electric generators. They are all sub sets so to speak.
For those who don't understand and would like to it's like classifying boats.
In the big picture of floaty things (we'll call them boats) we can break that into two main sub categories. Mono and catamaran.
In electricity generation (same big picture as boats) we can break that down into two main sub categories. AC and DC (alternating current and direct current).

If we consider mono hulls the same as AC generation.
With boats in the category of mono hull we can break that down further into sub categories such as displacement and planing hulls.
At this level I would be using sub classifications of brush-less and brush type alternators.

We all know displacement hulls can be further broken down into many more sub-sub categories such as Barges, tug boats, trawlers, Container ships, oil tankers etc etc that are intended for specific uses.
In electric terms (this time AC) alternators (seeing they make AC) can be further broken down into sub-sub categories once we determine if they fall into the brush-less or brush type of alternator.

In this case of a magneto on an outboard they are a sub-sub-sub category of generators.
We have Generator then Alternator then Brush-less Alternators and then Magneto.
In boat terms it would be Boat then Mono hull then Planing then ski boat
Magneto is not at the big end of the pecking order. It's nearer to the bottom just as a ski boat is way down the list in the order of classifications of boats..

Another sub-sub-sub category of alternator would be the charge coil on your outboard. Another sub-sub category of alternator would be the 'generator' in the shed you use when the power goes out (which can be broken down into many, many different sub-sub-sub and then some more sub categories) or the alternator in your car which can be broken down further as well.

I'll leave out the catamaran hull comparison to the DC side of power generation as magneto was what we're talking about and I have some things to do like get some firewood but if someone wants to know more then say so.

It's not rocket science.
Big picture is electricity is generated by a generator that is broken down into sub categories called Alternators (AC) and Dynamo's (DC) which are broken down into sub-sub-sub categories such as brush-less and brush type and then magneto's (in the AC side of things).

As with everything there are exceptions. Solar power and batteries are an exception to the rule of DC electricity generation. They give a pure DC output whereas dynamo's don't hence why they deserve their own category of electricity generation.

How's that Fed??

How come condenser's (capacitor's) weren't mentioned with points in the ignition system?
And don't ask where hydro-foils fit into boat classifications. ::)

[chappie]

wow Finga, for a while there, in the middle, i really started to believe i understood some of that.

[finga]

Sorry about that. Just read the bold black bits and it'll be clearer.
The rest is waffle in reality.

[oldboot]

The truth is over time all the words have been used indiscriminately and truly without any reference to any real meaning they may have.

In the grid connect, building based AC electrical trades, generators, alternators, magnetos, dynamo's......who cares because the vast majority of workers never actually work on any of them.......they simply connect the wires to the supply provided.
Thus no distinction is made in the trade.

As far as dynamo's being DC.....in my youth anybody who had a pushbike with lights on it had a thing that had "dynamo" printed large upon it.....truth to tell many of them produced true AC..(it had no comutator, that was simpler and cheaper)..the one on my bike certainly did...i think I still have it somewhere...

So incorrect and non specific use of all the words is very very common.

BUT..if you go to anybody in the auto trades (the DC world) and say "generator" that means something very specific and that is a device that produces DC in a particular way and is not found on modern cars, likewise if you say the word "alternator" the vision of something very specific comes to mind and with that comes expectations of performance.

Likewise the word "magneto" refeers to something in a particular form and it is specific to small engines, a coil usually mounted under or behind the flywheel and acted on by permanent magnets, usually mounted on the flywheel.

Regardless of it being configured for ignition, charging or lighting purposes, the appearance, physical form and principle of operation remains the same...they are all magnetos by convention in that industry.


As far as going to a parts suppler and asking for a coil that fits under the flywheel of an outboard.....they will probably not use the word "magneto" at all in the parts listing.
It will almost certainly say "charging coil" or "ignition coil" and in many cases particularly where there is a modern ignition it will be one and the same coil and part of the same assembly.

My point being that people very commonly expect "alternator" type performance and behaviour like in their car from the chaging system in their outboard, and thus fail to understand many things.

cheers

[Bros]

Anything that generates electricity in an AC wave form is called and Alternato

Well I might jump into this useless conversation. I have worked in Power Stations for most of my life from 30mw to 480mw units and everyone had a generator to make electricity the word alternator was never mentioned anywhere.

So how's that for confusion.

[finga]

The truth is over time all the words have been used indiscriminately and truly without any reference to any real meaning they may have.
Bullsh!t

In the grid connect, building based AC electrical trades, generators, alternators, magnetos, dynamo's......who cares because the vast majority of workers never actually work on any of them.......they simply connect the wires to the supply provided.
Thus no distinction is made in the trade.
Bullsh!t. In fact you would not pass an electrical trades if you did not know the difference between them.
That is easy for someone not in the trade to say about the trade.

As far as dynamo's being DC.....in my youth anybody who had a pushbike with lights on it had a thing that had "dynamo" printed large upon it.....truth to tell many of them produced true AC..(it had no comutator, that was simpler and cheaper)..the one on my bike certainly did...i think I still have it somewhere...
But they are an alternator. Just because it has dynamo written on it doesn't mean that's what it is.
Using that logic a Ford Mustang is a horse. An AC Cobra is a snake. A Pride Panther is a cat

So incorrect and non specific use of all the words is very very common.
Because of all the misinformation given out willy nilly by those trying to bullsh!t.
You talk specifics. So do I.

BUT..if you go to anybody in the auto trades (the DC world) and say "generator" that means something very specific and that is a device that produces DC in a particular way and is not found on modern cars, likewise if you say the word "alternator" the vision of something very specific comes to mind and with that comes expectations of performance.
What your talking about is indeed a dynamo but it was dumbed down to generator as a very generalised term for mainly clients of those trades who had to fix them or work on them.
A dynamo is still a generator. So is an alternator and so is a dynamo.
I know who call the car's alternator the generator. Still right but not specific.
Google it. Definition of a dynamo. DC output.
Modern cars have an alternator because they're an alternator. They give out an AC waveform which is then turned into DC via the rectifier.

Likewise the word "magneto" refeers to something in a particular form and it is specific to small engines, a coil usually mounted under or behind the flywheel and acted on by permanent magnets, usually mounted on the flywheel. That produces a spark to make the spark plug spark.
Go to Crowley Marine site and show me one mention of the word magneto. Coils is the norm. Maybe there's a reason for that??
http://www.crowleymarine.com/

Regardless of it being configured for ignition, charging or lighting purposes, the appearance, physical form and principle of operation remains the same...they are all magnetos by convention in that industry.
Bullsh!t. A huge difference in them. Find me one reference to a well known parts manual where a lighting coil is called a magneto.
As far as going to a parts suppler and asking for a coil that fits under the flywheel of an outboard.....they will probably not use the word "magneto" at all in the parts listing.
I wonder why?? Because they're not magneto's
It will almost certainly say "charging coil" or "ignition coil" and in many cases particularly where there is a modern ignition it will be one and the same coil and part of the same assembly.
Show me one part where a lighting or charge coil is built into the ignition coil.
You don't get too many true magneto's at all on outboards since the 1950-60's. Generally there is a coil which generates enough Ummff to enable the ignition coil to make a spark happen at the spark plug.

My point being that people very commonly expect "alternator" type performance and behaviour like in their car from the chaging system in their outboard, and thus fail to understand many things.
My point is people talk bullsh!t.
What should I call the 800w alternator sitting under the bench and what should I call the 50MVA alternators I worked on during my stint with a supply and generation authority?
One is a small output as compared to the other just like the output of a boat alternator is less then the output of an alternator in a car (usually).
Amount of output has no bearing on what something is called in this line of argument.
Terms are specific.
Google the terms generator, alternator, dynamo and magneto
Generalisations are not specific and misleading.
cheers

I might go and join TOL seeing it's DDD.

[finga]

Well I might jump into this useless conversation. I have worked in Power Stations for most of my life from 30mw to 480mw units and everyone had a generator to make electricity the word alternator was never mentioned anywhere.

So how's that for confusion.
Did you just call them generators?
Truly speaking the complete unit is a generator as it is converting mechanical energy into electrical energy.

What did you call the end of the generator that had the big wires coming out of it?

[Bros]

A couple of examples Generator Circuit Breaker, Generator Transformer, Generator Protection, Generator Earth Fault, Generator Overcurrent, Generator Differential protection, Bearing vibration and bearing temperature sensors were labeled Generator bearing TS (Turbine side) Generator bearing ES ( Exciter side) I could go on but this is a sample.

The bit that drove it was just called the Turbine.

The whole unit was called a TurboGenerator.

That should muddy the water.

[MudRiverDan]

I always thought that a magneto was associated with points, sends a spark per revolution.
Also charge battery like an alternator.

While and alternator just charged the battery soley, and relys on the coil and EFI/chip for spark/timing.


Pretty sure a generator works on the same principles, just is usually heavier and used for DC applications, like supplying intermittent power to a factory or just a high powered drill on back of a truck.

So an alternator is probably cruder or the same as a magneto in design, it just has the help of other technology.

In saying that.. I will throw a spanner.. a generator and a magneto are very similar as the output increases as the rpm increases.

Alternator has a regulator to regulate output.

[finga]

A couple of examples Generator Circuit Breaker, Generator Transformer, Generator Protection, Generator Earth Fault, Generator Overcurrent, Generator Differential protection, Bearing vibration and bearing temperature sensors were labeled Generator bearing TS (Turbine side) Generator bearing ES ( Exciter side) I could go on but this is a sample.

The bit that drove it was just called the Turbine.

The whole unit was called a TurboGenerator.

That should muddy the water.
What did you call the bit the turbine drove?

[Bros]

What did you call the bit the turbine drove?

Generator.

[finga]

And is it AC or DC that comes out of the 'generator'?

[Bros]

Alternating current

[finga]

Come on chaps this is 1st year electrical theory.
A "Generator" is a device that directly produces a DC output, as found in cars prior to the 70's..most usually it is a device that rotates a comutated (changing) spinning field winding past a stationary winding to produce a rough DC output.....output voltage is regulated by varying field current....a generator does not have a rectifier following the windings.


Well I might jump into this useless conversation. I have worked in Power Stations for most of my life from 30mw to 480mw units and everyone had a generator to make electricity the word alternator was never mentioned anywhere.

So how's that for confusion.


What did you call the bit the turbine drove?


Generator.


And is it AC or DC that comes out of the 'generator'?


Alternating current

So your saying a generator is something that gives an AC output and oldboot is saying a generator gives a DC output.
Something does not add up here.

And I'm saying an electrical generator is a name given to a group of machines that convert mechanical energy into electrical energy that can be either sub categorised as having an AC output (which is known as an alternator) or having a DC output (which is known as a dynamo).
Who's right?
http://www.thefreedictionary.com/Electric+generator
http://www.britannica.com/EBchecked/topic/182624/electric-generator
http://encyclopedia2.thefreedictionary.com/electric+power+generation

[Bros]

Oldboot is right and so am I.

Generators was the term used to describe a machine that gave a DC output.

Alternator was a term that gave an AC output.

With the disappearance of DC generators from the scene the term Generator has been used to describe both AC and DC machines (if you can find one), its the way our language evolves. With small units e.g. automobiles the term Alternator has stuck but for larger AC machines they are refereed to as Generators for power stations this has always been the case.

Don't lose any sleep over it as very few people would know of a DC generator I haven't seen one for many years.

[finga]

I disagree there. And disagree a lot.
Things cannot change names just like that. One minute a DC thing and the next an AC thing.
A dynamo gives DC output.
An alternator still gives AC output. They did not stop giving out AC.
Your both right because you both have used the name that describes the family of machines. Generators.
Exactly the same as describing a graphite or a fibreglass fishing rod simply as a fishing rod.
Both right but not specific.
What does Google say a dynamo and an alternator are?

[oldboot]

Finga mate...get used to the idea..its a world of change.

And there have always been different industries using different ways of describing things and if one works across different disciplines one has to get used to using the correct term in context.

In large scale power generation for the purposes of public supply, there is no need for a variety of discriptive terms, because they have not used DC generation since the time of Edison....further worldwide all the big things they make electricity with probably vary very little in type, form or principle of operation.


I have a thing in my shed that has a motor and produces 240V AC out of a 3 pin socket..I would not think of calling it anything other than a generator.... but I would not dream of going to an auto electrical supplier and asking for a diode pack for the generator from my toyota you'd be guaranteed of one of those " this bloke is an amateur" looks and would probaly get charged retail for your stupidity.

cheers

[Bros]

Oldboot described it well end of story.

[finga]

So what's your definition of generator, alternator, dynamo and magneto Bros?
Seeing your entering the argument I would appreciate the 'knowledge'

Oldboot started this by saying the thing that charges the battery in a boat is not an alternator. It's a magneto. He wanted to get specific so better stay specific.


Finga mate...get used to the idea..its a world of change.
Since when did electrical principles and theory change?? Since the time of critical length I suppose. (I would still like to read the principles of critical length in a text book or journal one day but cannot find any reference to it)
So if I start calling a dynamo a goggomobile and some people start calling a dynamo a goggomobile then it is a goggomobile??
Goggomobile hasn't been used for years either. Or how about calling it a scallywag??

And there have always been different industries using different ways of describing things and if one works across different disciplines one has to get used to using the correct term in context.
Bullsh!t. You wanted to get specific in terminology by saying the alternature in an outboard motor is actually a dynamo.... then I get specific in terminology. Anything that generates electricity can be called a generator in the same context a 4 stroke direct injected, turbo charged outboard can be called an engine. It is an engine..... but more specifically it is a 4 stroke engine with fuel injection and a turbo charger on it.
In large scale power generation for the purposes of public supply, there is no need for a variety of discriptive terms, because they have not used DC generation since the time of Edison....further worldwide all the big things they make electricity with probably vary very little in type, form or principle of operation.
Where did DC generation come up in regards to electricity distribution in towns?
Yeah. Generation for distribution has not changed much since Edison. They have always used an alternator to generate AC. It's part of electrical theory. Every first year knows that

I have a thing in my shed that has a motor and produces 240V AC out of a 3 pin socket..I would not think of calling it anything other than a generator.... but I would not dream of going to an auto electrical supplier and asking for a diode pack for the generator from my toyota you'd be guaranteed of one of those " this bloke is an amateur" looks and would probaly get charged retail for your stupidity.
What does the unit do?? It converts the energy stored in a fossil fuel to mechanical energy which is then converted to electrical energy. A classical definition of an electrical generator. The complete package may also be known as a generator set as it has the mechanic bits and the electrical bits combined in one compact unit....which it has. At one end is an engine of some description and at the other end is an alternator and combined as a set they generate electricity... hence generator set... which has been shortened to gen set by many or just plain generator.
The alternator in your car is called an alternator because it is
cheers
So why did you call a charge coil a magneto then Oldboot??
The term magneto 'went out' years ago and the term charge coil is in common use.


In these small motots it is not an alternator, it is magneto.....there is a very big difference.

A magneto will generate huge volatges when run unloaded like hundreds of volts..this will snot the diodes or regulator.
cheers
So what is the differences between a magneto and an alternator?
Why isn't it an alternator? Why isn't it simply called a generator?

Why is it when you google 'definition of electrical generator' or 'definition of magneto' or 'definition of alternator' or 'definition of dynamo' you do not get what you are trying to tell us what a generator is, an alternator, a dynamo or a magneto are?

You started the specifics in terminology. Stay specific.

So if I went into...say Mossop's tackle and asked for a fishing rod what would I get??
What would I get if I went into Mossop's tackle and asked for a 6' 2 piece graphite rod with line weight of 2-4kgs and casting weight of 5-12gms suitable for a spinning reel?
Answer: A fishing rod. But with one been more specific in definition.
Same argument can be submitted with the way you've used the term generator.
Anything that puts out a voltage can be correctly termed as an electrical generator.
But the use of the electrical generator can further define what sort of electrical generator it is??

Whilst we're at it
What voltages can be expected in a charge coil on an outboard if left without load?
What sort of load is needed so these huge voltages are not generated?
What effect does the inherent characteristics of the rectifier, and more then likely regulator, have on these huge voltages coming from this 'unloaded' charge coil?
How can the charge coil be 'unloaded' if there is a rectifier (usually with built in regulator) connected to the end of the wires??
What can be done so that a charge coil will never achieve the voltage levels your talking about?

[Fed]

Goodonya Finga, bore it up him mate!
Just so he doesn't try & squirm out by writing a full page about what means what, when you say charge coil you mean the stator coils which produce the power to charge the battery right?
Just so we're clear my OMC manual calls the following...

Stator coils= Supply power the charge the battery.
Charge coil/s supply HV power to the powerpack then on to the ignition coils.
Sensor coil supplies signal to the powerpack.

We all on the same page?

Go for it Oldboot, now remember this is a discussion to work out what's right and NOT an argument.

http://ausfish.com.au/vforum/images/misc/quote_icon.png Originally Posted by oldboot http://ausfish.com.au/vforum/images/buttons/viewpost-right.png (http://ausfish.com.au/vforum/showthread.php?p=1307442#post1307442)
In these small motots it is not an alternator, it is magneto.....there is a very big difference.

A magneto will generate huge volatges when run unloaded like hundreds of volts..this will snot the diodes or regulator.
cheers

RUBBISH!

[finga]

Goodonya Finga, bore it up him mate!
Just so he doesn't try & squirm out by writing a full page about what means what, when you say charge coil you mean the stator coils which produce the power to charge the battery right?
Just so we're clear my OMC manual calls the following...

Stator coils= Supply power the charge the battery.
Charge coil/s supply HV power to the powerpack then on to the ignition coils.
Sensor coil supplies signal to the powerpack.

We all on the same page?

Go for it Oldboot, now remember this is a discussion to work out what's right and NOT an argument.

RUBBISH!
I had a look in the manual for old Tohatsu I had as well.
On page 15 and 16 of the manual there is a coil plate assembly (Part#3PO-06002-0), an alternator (part #3PO-06023-0), an exciter coil (Part #3G3-06021-1) and an ignition coil as well as a CDI.
On the old tower of power we have a stator (http://www.crowleymarine.com/parts/2782.cfm)and a trigger plate assembly (http://www.crowleymarine.com/parts/292.cfm).
On the Honda we have a coil assembly-exciter and a coil assembly-charge (http://www.boats.net/parts/search/Honda/Outboard%20Engine/2000/BF15AY%20LAS%20VIN%23%20BAAS-1500001%20TO%20BAAS-1599999/FLYWHEEL/parts.html) and an ignition coil (http://www.boats.net/parts/search/Honda/Outboard%20Engine/2000/BF15AY%20LAS%20VIN%23%20BAAS-1500001%20TO%20BAAS-1599999/IGNITION%20COIL/parts.html)

[oldboot]

I was trying to be helpfull it is plain and obvious that you are not interested in helping anybody or even improving your own understanding.

You can continue with your pointless and ignorant arguments.

The fact reamins, if you run most outboard charging circuits with out a battery or some other load, you have a very good chance of blowing up the rectifier or regulator pack.

The evidence for this is very clear...most outboard manuals mention this.

Most "rectifier" packs as fitted to small outboards contain no regulator....any body who knows the first thing about outboards knows this.

cheers

[Fed]

The fact reamins, if you run most outboard charging circuits with out a battery or some other load, you have a very good chance of blowing up the rectifier or regulator pack.

The evidence for this is very clear...most outboard manuals mention this.
OK, how about quoting verbatim from some of these manuals?

[finga]

I was trying to be helpfull it is plain and obvious that you are not interested in helping anybody or even improving your own understanding.

You can continue with your pointless and ignorant arguments.

cheers
My point is you are wrong, very wrong. And you are just trying to justify yourself and trying to 'bluff' others into thinking you know all.
Definitions are definitive. That's their purpose in life. Here-say is just that.
I was trained to be exacting in my trade otherwise people died.
I was trained to be exacting as an inspector because that was my job.
I was not trained to call something by any other name then what it is. Things have definitive names for a reason. That reason is so everyone knows what they're talking about.
Things cannot change name just because one name has just gone out of fashion or someone has decided to call it something different..

I am very tired at the amount of mis-information there is available.
Hopefully people have googled the definitions of generator (http://www.google.com.au/search?q=definition+of+stator&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-GB:official&client=firefox-a#pq=definition+of+an+electrical+stator&hl=en&cp=37&gs_id=z&xhr=t&q=definition+of+an+electrical+generator&pf=p&sclient=psy&client=firefox-a&hs=kS6&rls=org.mozilla:en-GB%3Aofficial&source=hp&pbx=1&oq=definition+of+an+electrical+generator&aq=f&aqi=&aql=&gs_sm=&gs_upl=&bav=on.2,or.r_gc.r_pw.&fp=1757f0b1e7f04f65&biw=1280&bih=826), alternator (http://www.google.com.au/search?q=definition+of+stator&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-GB:official&client=firefox-a#pq=definition+of+an+electrical+stator&hl=en&cp=38&gs_id=27&xhr=t&q=definition+of+an+electrical+alternator&pf=p&sclient=psy&client=firefox-a&rls=org.mozilla:en-GB%3Aofficial&source=hp&pbx=1&oq=definition+of+an+electrical+alternator&aq=f&aqi=&aql=&gs_sm=&gs_upl=&bav=on.2,or.r_gc.r_pw.&fp=1757f0b1e7f04f65&biw=1280&bih=826), dynamo (http://www.google.com.au/search?q=definition+of+stator&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-GB:official&client=firefox-a#pq=definition+of+an+electrical+stator&hl=en&cp=34&gs_id=2z&xhr=t&q=definition+of+an+electrical+dynamo&pf=p&sclient=psy&client=firefox-a&rls=org.mozilla:en-GB%3Aofficial&source=hp&pbx=1&oq=definition+of+an+electrical+dynamo&aq=f&aqi=&aql=&gs_sm=&gs_upl=&bav=on.2,or.r_gc.r_pw.&fp=1757f0b1e7f04f65&biw=1280&bih=826) and magneto (http://www.google.com.au/search?q=definition+of+stator&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-GB:official&client=firefox-a#pq=definition+of+an+electrical+stator&hl=en&cp=34&gs_id=2z&xhr=t&q=definition+of+an+electrical+dynamo&pf=p&sclient=psy&client=firefox-a&rls=org.mozilla:en-GB%3Aofficial&source=hp&pbx=1&oq=definition+of+an+electrical+dynamo&aq=f&aqi=&aql=&gs_sm=&gs_upl=&bav=on.2,or.r_gc.r_pw.&fp=1757f0b1e7f04f65&biw=1280&bih=826) and found a magneto's job IS to ultimately supply spark to a spark plug. As seen here
(http://www.google.com.au/search?q=definition+of+magneto&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-GB:official&client=firefox-a)They would have also found anything who's output is AC can be classed as an alternator (http://www.google.com.au/search?q=definition+of+alternator&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-GB:official&client=firefox-a) (even says so in the parts manuals as mentioned above) and anything that puts out DC is a dynamo (http://www.google.com.au/search?q=definition+of+dynamo&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-GB:official&client=firefox-a)and all the three of them can be grouped together under the family name of generators in exactly the same manner in which a planing mono hull, a displacement mono-hull and a sailing catamaran can all be grouped together under the family name of boat.
Also...A true alternator is a generator who's output is AC. An alternator cannot be classed as a "true alternator" (as mentioned by Oldboot in post #23 on page 2 of this thread) just because of the level of current output. As long as there is AC coming out of it it's an alternator. That's the definition of alternator....AC output. Nothing else mentioned there at all about amount of current output and I'd love to see a recognised reference that states that an alternator is just an alternator because of the amount of current it can produce.

Oh sh!t. Look at what else is in post #23. Oldboot has called the gismo that gives power to your home.....an alternator.
There ya go Bros. Your wrong because Oldboot says otherwise.
An alternator is a device where a electricaly energised windings are spun past a stationary field or fields to produce electricity......the output voltage is regulated by varying the field current.......this is what produces electricity for most of our homes and what you have in your car.......mostly only very large outboard motors have true alternators.
So even with that statement I have questions.
Oldboot says that only very large outboards have true alternators just like alternators supply power to out homes.
So if something that puts out only 6 amps is not an alternator, how can something that puts out about 40A be classed as atrue alternator when compared to a 200MVA alternator in a power station...relatively speaking???
For those who are wondering how stator came into the argument then that's easy. A stator is a crucial part of any form of electrical generator whether it be an alternator or dynamo.
A stator normally consists of a number of coils.
If you click on the links I included with the Mercury (Tower of Power) and Honda parts you'll see the differences in physical appearance.

So how about answering some questions I've asked up the page a little bit Oldboot?
The answers will help others in understanding what exactly happens and how to reduce their exposure to the risks you've been telling every one about.

I'll ask the questions again.
What voltages can be expected in a charge coil on an outboard if left without load?
What sort of load is needed so these huge voltages are not generated?
What effect does the inherent characteristics of the rectifier, and more then likely regulator, have on these huge voltages coming from this 'unloaded' charge coil?
How can the charge coil be 'unloaded' if there is a rectifier (usually with built in regulator) connected to the end of the wires??
What can be done so that a charge coil will never achieve the voltage levels your talking about?


I don't know why but I'm reminded of a saying:
If you can't dazzle them with brilliance baffle them with bullsh!t.

[BM]

Been quite a while since I measured this but I seem to recall the unloaded AC output from the stator on an inline 6 Merc being around 28V, and the unloaded rectified DC output (but not regulated) at about 22V.

Of course introducing a load (ie: a battery) pulls the free floating DC output down to normal charging voltage levels.

However, long runs with a healthy battery can potentially see this system overcharge the battery as there is no regulation. Although, the charging current is only about 8A.

Cheers

[Fed]

Those numbers look a lot more believable than the hundreds of volts Oldboot was talking about, 20-30V is was I was expecting but I've never measured it and never seen any documentation on it in any Merc or OMC manual.
Now I'd like to bet all the diodes are rated way higher than 30 Volts too, have you ever seen a rating on a Merc one BM?

[oldboot]

As usual Finga you can not accept that others know more than you.

Just like you can not accpet that all those electrical standards you spent years inspecting to have absolutly no application or authority in DC automotive or marine electrical.

You find that your limited knoweledge from a trade with a very very narrow and limited understanding of elecricity lets you down yet again.

As I said again......most if not all of the simple "rectifiers" used in small outboards contain no regulation.

But if you read and understood a few outboard motor manuals you would know that.

If you read the test procedures in the manual and have any understanding of electronics at all. the prescribed tests on the basic rectifiers are simple diode tests and show nothing more than 2 diodes.

Simple diodes do not and can not provide a load. that I understood in yr10 high school.

In most small outboard motors the charging coil is a center tapped arrangement with the center tap earthed and a two diode full wave centre tapped rectifier arrangement.

The problem is the unloaded voltage of the charging coil is capable of exceeding the PIV ( peak inverse voltage) of the diodes and blowing them.

Why these diodes have such a low PIV is anybodies guess....I supose it sells parts.

Briggs and stratton ( and others) overcome this problem by using a single winding with a single diode....this gives a less efficient and higher ripple charging voltage but if the battery is disconnected so is the diode.

To put it in a way you will understand.
If you run a CT meetering transformer open circuit it can produce very high voltages that it can not in normal operation..this is exactly the same principle.

My undersanging is that at High RPM an unloaded ouboard motor charging coil is capable of producing voltages in the order of a couple of hundred volts peak to peak between the oposite ends of the coil.......the PIV of the diodes in a rectifier intended for 12 volts may be as low as 50 or 100 volts.

Remember if you are using a typical multi-meter to measure the voltage it will be measuring either average or RMS AC......it will not be capable of reading the peak to peak voltage.......even assuming a pure sinewave ( which it wont be), the peak to peak voltage will be 2.88 times the average voltage read.

that voltage measured..was that at the output of the rectifier in AC, DC or what, or across the opposite ends of the stator coil.....there is a potential doubling there too.

That voltage ..at what RPM was that measured.

these direct verbatum images come from a genuine mercury service manual for a 30 Hp motor that starts manufacture in 1994.


cheers

[Bros]

I was trained to be exacting in my trade otherwise people died.
I was trained to be exacting as an inspector because that was my job.

Well bugger me I didn't know there was trade for nitpickers.

[Fed]

That's interesting Oldboot I wonder if it's a new Merc thing as I couldn't find anything about it in my OMC manual and I don't believe I've ever read anything about it in older Merc manuals that I've had. When I've sold boats in the past I always gave the new owner my manual so I can't refer back to them now.
Anyway, the closest I could find in my current OMC manual is below, my scanner isn't playing ball so you'll have to take my word for it.

Battery "On-Off" Switches if you are using a battery master "On-Off" switch in the engine's 12 Volt electrical system, be sure that the switch is equipped with a "make-before-break" circuit to protect the engine's battery charging system. Avoid switching while the engine is running and never turn the switch "off" while the engine is running.
Do I still have to piss off or can we have a group hug & move on?

[finga]

Thanks BM for the real world figures.
Muchly appreciated. A lot different to the theoretical hundreds of volts Oldboot is talking about.

And that it from this dumb sh!t sparky
Oh, hang on. No it's not.
Still haven't got questions answered. How can a dumb sh!t sparky learn if questions aren't answered??

What voltages can be expected in a charge coil on an outboard if left without load? OK. Oldboot has a theoretical hundred of volts achieved and BM has a real world reading of 28V on a Tower of Power 6 cylinder Merc. What to believe? Theory or real world??

What sort of load is needed so these huge voltages (mentioned by Oldboot) are not generated?

What effect does the inherent characteristics of the rectifier, and more then likely regulator, have on these huge voltages coming from this 'unloaded' charge coil? Peak inverse voltage mentioned.

How can the charge coil be 'unloaded' if there is a rectifier (usually with built in regulator) connected to the end of the wires?? Peak inverse again??

What can be done so that a charge coil will never achieve the voltage levels your talking about (Oldboot)?

How can people limit the risk of these hundred of volts generated by a charge coil on an outboard motor?
This is very simple. Even a very narrow minded sparky who can not accpet that all those electrical standards you spent years inspecting to have absolutly no application or authority in DC automotive or marine electrical. who's limited knoweledge from a trade with a very very narrow and limited understanding of elecricity lets you down yet again...... can do it.

I never knew DC had no place in an electrical fitter mechanics world. Maybe that's why I've never read about critical length as well??
I haven't just inspected other electricians work. I worked pulling wires in the real world too. Actually I pulled wires ranging in size from teeny weeny to HUGE which have been made from copper, aluminium and steel in voltages up to 132,000VAC and somewhere on a wall there's a certificate at says I'm even qualified to run,join, terminate etc etc fibre-optics. But what would I know. I'm only a sparky who's been in the industry since 1982, and as such, should only work in AC in voltages up to 415V....and that's it.


I'm willing to learn. Just by answering the above questions in one or two lines would be a start.

[BM]

As I stated from the outset it was quite some time ago I measured that. It would have been measured with my trusty Jaytech multimeter that I bought when I was working for them a long long tine ago but I don't think it's a true RMS meter.

I don't recall if it was at low rpm or higher rpm. I'm sure I would have varied the rpm to see the output change (direct across the stator output wires) and also from the rectifier output.

The rectifiers I used to replace originals came from at the time Dick Smith, but now they are stocked by Jaycar and not Dickies. They are a 35A 400V bridge reccy. Why those ratings? Coz it's the only one they sell!!

I have an immaculate 20hr old 1983 Merc 115 here at present that I bought cheaply a while ago. Bottom seal let water in and stuffed the crank. Sourced a crank from the US and just need to put her back together. I'm not in any rush to reassemble it but I will test it when it's up and running and report back with the readings. Might be a month though....

I just had a quick chat with my good mate and mentor with over 45 yrs in the marine trade and he recalled several incidents. 1 involving a V6 Merc with a regulator that had the battery lead come off. It blew the electronics in the boat from the voltage surge. Rectifier and regulator survived.

Another case saw a V4 Johno that the owners son switched off the battery whilst under way. Result was that all electronics in the boat including tacho and the lot got blown. Rectifier and regulator in this case also survived.

Both cases were at high rpm.

Like me the 28V figure for the Merc stator rang true to him also but he couldn't recall higher rpm voltage readings.

And in his words to which I could not agree more "it's not relevant".

I will get readings from the engine I have when it goes back together and I'll do a high rpm (destruction) test as well although the 2 examples I quoted saw no failure to any charge components.

Cheers

[finga]

Good stuff. Thanks for the information from another source who operates in the real world BM.
Sounds like Myth buster stuff BM and thanks for introducing an idea into this tiny, useless mind.
I should get my Tower of Power out and do the same. It might be a bit quicker seeing it's actually together and going...if I put a battery and some fuel in it.
I just so happen to have some 50A 1000V bridge rectifiers sitting on the dash of Mrs Palmer for the same purposes that you use them and I reckon I could risk losing one.
I reckon the old Fluke 116 will be good enough to measure whatever happens.

Or I could put one or two of them on the little Honda and get the same end result.

Maybe Oldboot will be able to bung a meter on his Merc as well to get a real world reading??
Not hard. Unplug rectifier/regulator and shove a multi-meter on the leads and give it a run.
I'm sure he'd have a full wave bridge rectifier lying about as well to test that.

Cheers and thanks
Scott

[BM]

The Jaycar reccies are only $5.95 and if you have an engine handy you could provide answers this arvo!

Not wishing to trivialise the debate, but knowing the unloaded voltage of the charging system in a situation that is not normal operational conditions helps us how??

[PinHead]

what are your trade qualifications oldboot?

[oldboot]

Comming from an electronics background where even the cheapest and pissiest diode has a PIV of a couple of hundred volts, I was originally suprised by the whole idea that an unloaded curcuit could blow the rectifier pack.

Till it was pointed out to me that some of these diodes intended for 12 volts systems only have a PIV in the order of 50 or 75 volts....the whole problem could be solved by the use of a diode with a decent PIV....like a 35 amp metal cased bridge from Dickcartandy's

But like many things in auto & outboard motors, some of these parts have not changed since the 60's

As for "MOST of these rectifiers having a regulator".....it simply is not the case particularly in smaller motors....and most outboard service manuals will give detail on that, if you simply chose to read.

ANY outboard that does not have electric start is most likley to have nothing more than a simple rectifier.
Any outboard that did not come with the rectifier fitted will have nothing more than a simple rectifier available as a optional part.

The fact is that the charging circuits on most outboard motors currently in service are disgustingly crude, inefficient, low output things that can have some particular traps.

The simpleset systems remain unchanged since charging systems were first fitted to outboard motors, and those were derived from charging systems found on stationary motors and motrocycles dating back pre-war

They can not be expected to perform or behave like the modern "alternator" we find in most of our cars.

People get caught, every week failing to understand this and the implications that roll from it.

Unfortunately none of the manuals have all the cautions that should be due.

Mercury warn against battery disconnection and detail a procedure for running with the battery disconnected.

Mercury warn of the total lack of regulation in simple rectifier circuits and council battery maintenence.

As attached...Mercury list, open circuits in the battery circuit as a cause of charging system failure.

my seloc manual for evenrude warns against switching dual battery switches while the engine is running.

my seloc manual for evenrude warns not to run "maintenance" free batteries with non regulated rectifier circuits.

my seloc manual for evenrude councils use of the correct size of battery for the charging system, and refeers to information in the specifications section..information that is not there.

If you are going to test the output voltage of an unterminated charging coil......you may need to tank the motor because you will need to give it quite a few revs to get maximum voltage.....

See the graps attached.......the graphs show current capacity in a functioning charging system with a battery connected...there is no current without voltage..and the OC voltage will rise in similar fashon.

As for what load or lack of it will be required to cause these problems..well that will vary depending on the charging system and the components.

BUT the recomendation remains, do not run a charging system without the battery connected unless you disconnect the rectifier or regulator first.

cheers

[finga]

God bugger me there's some waffle.
Where did the regulator stuff come from??

Anyways....how about answering some questions that have been directed to you Oldboot seeing you know all.
One or two lines is all that's needed if possible.

What voltages (within a hundred volt range) can be expected in a charge coil on an outboard if left without load...say in the instance of your motor Oldboot?

Why wasn't magneto mentioned in all the literature you've just put up Oldboot?
Charge coils and stators were mentioned.
Nowhere was it mentioned or specifically said that rectifiers blow up. Just charge systems may be damaged. Damage could be the risk of a loose wire hitting the flywheel knocking some insulation off or the wires shorting out somewhere. My guess would be wires shorting out causing a problem to the rectifier and/or regulator due to current and not things blowing up due to hundreds of volts placed across them..


What sort of load is needed so these huge voltages are not generated....say in the instance of your motor Oldboot?

What effect does the inherent characteristics of the rectifier, and more then likely regulator, and any other electronics seen in a modern outboard have on these huge voltages coming from this 'unloaded' charge coil...but say in the instance of your motor?

What can be done so that a charge coil will never achieve the voltage levels your talking about Oldboot...say in the instance of your motor??

How can people limit the risk of these hundred of volts generated by a charge coil on an outboard motor ...say in the instance of your motor Oldboot?

At what current level does a 'nearly an alternator' grow up to become a 'true alternator' Oldboot??

And Pinhead has asked what your trade qualifications are.This even I may be interested in especially seeing an ordinary sparky has no idea about anything with DC.
Oh, hang on. Just had a stupid thought. We're talking about AC output as it's on the alternator side of the rectifier. Does that mean an auto electrician has no idea as it's AC??
What parts does your outboard motor have in common with an equivalent motor from the same manufacturer from the 1960's Oldboot??

Out of curiosity I looked at the owners manual for my 15hp Honda to have a gander at warnings.
Guess what the warning was on the first page inside the cover??
WARNING: The exhaust gas from this product contains chemicals known to the State of California to cause cancer, birth defects and other reproductive harm.
OH NO!!!! I'm gunna sell it now and buy an outboard that hasn't got that warning. Oh, hang on. I don't live in California. I'm safe :D

Why am I continually reminded of that saying about if you can't baffle them with brilliance baffle them with bullsh!t??

[oldboot]

YOU call everything I post Waffle, because you come to it with a preconcieved idea that it is wrong, you are better than me and you can not be bothered reading it and understanding it......an attitued I have found very common and have become well and truly sick of among "electricians".

What voltages can be expected...voltages in the order of hundreds of volts that is more than the order of tens of volts...I am not stupid enough to specifiy any figure on an item that may vary wildly due to its construction.

Now remember you need to measure the coil end to end and the peak to peak AC value, not the average or RMS value that your meter is capable of measuring......so go and get out your osciliscope......it is the peak to peak AC voltage that matters not the average, RMS or DC voltage.

If ya want to know get off your own lazy but and find out.

It is sufficient for me that the manufacturer makes certain recomendations and qualified people I have spoken to in marine dealerships confirm this.

I am not going to continue to argue an issue that is a KNOWN FACT......The boys in the marine repariers know about it because they regularly replace blown rectifier and regulator packs.

If you wish to ignore this.....off you go.

as for what load is required to prevent this high voltage being genertated......that too will vary greatly depending on the design.......But the manufacturers recomendations are clear.

If you are going to run the motor with the battery removed, disconnect the rectifier or regulator.


As for the use of words....you will never be satisfied.......all the words are and have been used indiscriminately and with reference to their real meanings for a very long time.

Regardless of any technical persons best efforts to use technicaly correct words, once the marketing people get hold of it all bets are off.

I have a book here titled "Testing Dynamos and Motors" by Smith, 10 shillings and 6 pence...it ..calls every item in the book that generates electricity a "Dynamo"...however being written for the electrical trades it does not mention permanent magnet machines except in pure theory.

In "Electriucal principles for the electrical trades" by Jenneson the text for electrical apprentices in the 80s and 90's, it uses the words generator as a general term for anything that makes electricity and Alternator a couple of times... but mostly it refeers to "machines" by their principle of operation..."series excited machines" and studiously avoids anything else.

I have an old stationary motors book here that I cant find at the moment but it has a whole chapter on "Magneto charging circuits".

In the days of manual switchboards, the manual rinnger was often refeered to as a "hand crank magneto ringer".

Words like Dynamo, magneto and such will be pretty well irradicated from manufacturers documents in relation to charging systems because they don't want to be seen as so old fashoned as to have such a thing in one of their motors.

An alternator regardless of its meaning is a much more modern and capable word.......than magneto, particularly when a few pages earlier there is a paragraph that says alternators are much more efficient than generators and that some boats have generators...obviously a paragraph lifted from a motoring manual and edited for use.

If you wish to continue to be pig headed, ignorant and nit picky...off you go...but don't expect me to play.

As for the use of old technology in outboard charging systems..I have manuals here that go back to '73 and as recent as 2005.

In Evenrude....appart from the combining of the regulator and rectifier into one unit on larger motors in arround "83.

The sections on charging circuits remain pretty well identical.....right down to the colours of the wires and the capaicty of the various charging circuit options and the items in pictures look pretty damn similar......except the older manual actuall has a bit more periferal information.

A true alternator in this case is what most people would expect to have in an automotive an marine context and that is one of those things driven by a belt and capable of regulating its own output by varying its field current.


As for my qualifications.
I am not going to play that silly game.

apart from to say that I have a trade certificate as a Technician and and 3 other cert 3 technical certificates, a certificate 4, communication and electrical licences among others.
I have worked on a very wide variety of equpment.

bear in mind that "Electrical fitter mechanic" is a certificate 3 qualification.

But the qualifications have absoluty no bearing on the facts..

If you don't understand the facts, don't argue with the manufacturers recomendations.

If you have been baffled by anything I have posted, you don't undrstand the facts.

cheers

[PinHead]

YOU call everything I post Waffle, because you come to it with a preconcieved idea that it is wrong, you are better than me and you can not be bothered reading it and understanding it......an attitued I have found very common and have become well and truly sick of among "electricians".

What voltages can be expected...voltages in the order of hundreds of volts that is more than the order of tens of volts...I am not stupid enough to specifiy any figure on an item that may vary wildly due to its construction.

Now remember you need to measure the coil end to end and the peak to peak AC value, not the average or RMS value that your meter is capable of measuring......so go and get out your osciliscope......it is the peak to peak AC voltage that matters not the average, RMS or DC voltage.

If ya want to know get off your own lazy but and find out.

It is sufficient for me that the manufacturer makes certain recomendations and qualified people I have spoken to in marine dealerships confirm this.

I am not going to continue to argue an issue that is a KNOWN FACT......The boys in the marine repariers know about it because they regularly replace blown rectifier and regulator packs.

If you wish to ignore this.....off you go.

as for what load is required to prevent this high voltage being genertated......that too will vary greatly depending on the design.......But the manufacturers recomendations are clear.

If you are going to run the motor with the battery removed, disconnect the rectifier or regulator.


As for the use of words....you will never be satisfied.......all the words are and have been used indiscriminately and with reference to their real meanings for a very long time.

Regardless of any technical persons best efforts to use technicaly correct words, once the marketing people get hold of it all bets are off.

I have a book here titled "Testing Dynamos and Motors" by Smith, 10 shillings and 6 pence...it ..calls every item in the book that generates electricity a "Dynamo"...however being written for the electrical trades it does not mention permanent magnet machines except in pure theory.

In "Electriucal principles for the electrical trades" by Jenneson the text for electrical apprentices in the 80s and 90's, it uses the words generator as a general term for anything that makes electricity and Alternator a couple of times... but mostly it refeers to "machines" by their principle of operation..."series excited machines" and studiously avoids anything else.

I have an old stationary motors book here that I cant find at the moment but it has a whole chapter on "Magneto charging circuits".

In the days of manual switchboards, the manual rinnger was often refeered to as a "hand crank magneto ringer".

Words like Dynamo, magneto and such will be pretty well irradicated from manufacturers documents in relation to charging systems because they don't want to be seen as so old fashoned as to have such a thing in one of their motors.

An alternator regardless of its meaning is a much more modern and capable word.......than magneto, particularly when a few pages earlier there is a paragraph that says alternators are much more efficient than generators and that some boats have generators...obviously a paragraph lifted from a motoring manual and edited for use.

If you wish to continue to be pig headed, ignorant and nit picky...off you go...but don't expect me to play.

As for the use of old technology in outboard charging systems..I have manuals here that go back to '73 and as recent as 2005.

In Evenrude....appart from the combining of the regulator and rectifier into one unit on larger motors in arround "83.

The sections on charging circuits remain pretty well identical.....right down to the colours of the wires and the capaicty of the various charging circuit options and the items in pictures look pretty damn similar......except the older manual actuall has a bit more periferal information.

A true alternator in this case is what most people would expect to have in an automotive an marine context and that is one of those things driven by a belt and capable of regulating its own output by varying its field current.


As for my qualifications.
I am not going to play that silly game.

apart from to say that I have a trade certificate as a Technician and and 3 other cert 3 technical certificates, a certificate 4, communication and electrical licences among others.
I have worked on a very wide variety of equpment.

bear in mind that "Electrical fitter mechanic" is a certificate 3 qualification.

But the qualifications have absoluty no bearing on the facts..

If you don't understand the facts, don't argue with the manufacturers recomendations.

If you have been baffled by anything I have posted, you don't undrstand the facts.

cheers

thank you very much for the huge laugh oldboot..the highlighted bit really got me seeing as your signature says : "Its the details, those little details, that make the difference." Isn't that just another way of saying nit picking.

Now..taking out all the uesless waffle..have you managed to answer the original question without all the rectifier, diode, flux capacitor crap?

[finga]

All that waffle and still cannot answer questions which had been asked about your outboard Oldboot so you should know it's in and outs and specifics.
Read the questions properly. "Its the details, those little details, that make the difference" you know.
You can never give a direct answer to any questions.
A question that requires a 3 word answer cops War and Peace. I might have to start calling you Julia

An example. A question I asked: What voltages (within a hundred volt range) can be expected in a charge coil on an outboard if left without load...say in the instance of your motor Oldboot?
Answer: 500-750V roughly.
How simple is that??

Ya just don't know the answers do you Oldboot??
All you say is just hearsay. There are no references to specifics. All a mate of mine and qualified people I have spoken to in marine dealerships and The boys in the marine repariers blah, blah, blah.

I am not going to continue to argue an issue that is a KNOWN FACT......The boys in the marine repariers know about it because they regularly replace blown rectifier and regulator packs.
Better tell BM he doesn't know his trade nor does his mate who's been in the game for 45 years if your referring that rectifiers only blow because someone disconnected the battery eh
Did you ask why the rectifiers and/or rectifier/regulators blew Oldboot? Or did you just assume they blew because of hundreds of volts going across them?? They can blow for other many other reasons I would have thought.
Who are these boys so we know where to take a boat to to get fixed?

as for what load is required to prevent this high voltage being genertated......that too will vary greatly depending on the design.......But the manufacturers recomendations are clear.

If you are going to run the motor with the battery removed, disconnect the rectifier or regulator.
Where is a reference that will confirm this high voltage that's in the hundreds of volts? What is hundreds of volts?? 102V or closer 879V. There is a broad spectrum that will cover hundreds of volts.
The recommendation is clear as mud if it's supposed to mean if you run your outboard without a battery your rectifier is going to blow because of hundreds of volts generated by the charge coil/stator. Does it say what will happen? No. It just says disconnect the rectifier. Why?? Doesn't say. Another assumption on your behalf maybe?

And I asked about YOUR boat. What load is required for YOUR outboard not the blow the rectifier and/or regulator in YOUR boat.

What is an easy way to stop YOUR rectifier from blowing from the hundreds of volts produced by YOUR outboard??

What voltage level (within a 100V) are we talking about in YOUR boat?

Pretty rude saying a technician in the calibre of BM does not know his trade. He has given first hand information and information from his good mate with 45 years experience in the industry and then for you, Oldboot, to tell him he's wrong.

[finga]

Oi Oldboot....what does your service manual call the battery charging thingo?? You know....the 'magneto' dodad???
And have you got a link to a service manual for your 30/40hp Mecury??
I suppose it'll be the same as models from 1997 one seeing outboards haven't changed since the 1960's

I have a service manual for 30/40hp Merc dated March 1997 and I nearly fell off my seat laughing.
Fairdinkum....I nearly peed myself. Actually I think a drop or two did squirt out.

Pinhead is gunna love this one.

[PinHead]

I don't know didly squat about diorectieswhatever. Nor about electricity..just a dumb fridgie.

[Spaniard_King]

Is this one of those posts that got out of hand ::)

Somewhere back on the first page the problem was sorted for the original issue.

As for the Honda.. said poster has not come back... bit like pi$$ing in the wind this thread.

[MyWay]

I can not believe .....this is still going on.....

can I be moderator please ....;D;D

[finga]

Yep, the thread goes on purely because someone wants to try and bluff people.

First Oldboot said old mate did not have a problem with his alternator. He may have had a problem with his magneto and asked if he's ever had a battery on his motor, and if not, then his rectifier will be, more then likely, 'stuffed' (and I'm thinking it's a 130hp Yammi. It ain't small nor would I like to rope start it all the time)

And this was the beginning......of the waffle
Fed said bollocks and then Oldboot went into his baffle them with bullsh!t routine.
Fed and myself said a magneto's task is to give spark to a spark plug.
Bollocks says Oldboot. A magneto charges.
I said an alternator does the AC bit and a dynamo does the DC bit.
Bullocks says Oldboot.
Oldboot has insisted that that is what people call the the gismo that charges now and terms change over the years. End of story. get over it.

I have asked Oldboot some direct questions to try and understand the DC world (which an electrician has no understanding of) a bit better.
No direct answers to the pretty specific questions.
I have done some research to try and understand where he's coming from and to try and answer the questions I have asked seeing he won't.

Then the argument of hundreds of volts generated by an open circuit charge coil.
Oldboot says there's hundreds of volts generated. BM has measured it at 28V and his mate with over 45 years experience said the same and Fed said this is what he thought the readings should be. Oldboot says bollocks. It's in the magnitude of hundreds.
To be honest I thought it would be a smidge higher then the 28V but not in the magnitude of hundreds of volts.

I like to learn and I am very open to 'suggestions' such as those from BM and Fed as to what's what.
Spaniard King may not know it, but, I have learnt a hell of a lot from him and likewise to Grand Marlin and many others here over the years.

And to answer the question of what is the easiest way to put a load across a charge coil to stop these "hundreds of volts" blowing a rectifier. Bung a light bulb or similar (ie test lamp) across the coil or coils. Instant load.


Yesterday doing a bit of research for another matter (thread in electronics about a 40hp Merc) I came across some Merc service manuals online.
What does Merc call the thingo that Oldboot insists is a magneto (remembering his references to his Merc manual like a bible)?? An alternator. Yep, Merc says the thing that does the charging on their outboards is an alternator. Not a magneto.
Yep. Oldboot has been continually arguing that an alternator is not an alternator even when his own service manual says it's an alternator.

And then reading the manual for the 30/40hp model of Merc I come across a warning about operating an outboard without a battery connected....remembering Oldboot saying all outboards will kill the rectifier due to hundreds of volts generated if you don't disconnect the rectifier when running without a battery...... I read with astonishment. (page 2B-13) of the manual available here (http://1manual.com/Mercury%20manuals/Service%20Manual%20PDFs/TwoStroke/814676r1/2b.pdf))
Operating Outboard without Battery
If desired (or in an emergency), outboards equipped
with an alternator can be started and operated without
a battery (either disconnected or removed) if
“Warning”, below, is followed.
WARNING
Before operating outboards with battery leads
disconnected from battery, the leads MUST BE
taped off (insulated) or positioned in a manner
that prevents a completed circuit between the
leads. Electric wiring harness MUST REMAIN
CONNECTED to electric starting models in order
to “Stop” the outboard with the ignition key.

No mention of disconnecting rectifiers is there? Just tape the battery terminals and jobs done. Easy as if you don't want a battery.

The manual for the 25hp version mentions the warning Oldboot refers to.
It seems to me there is a correlation if there is a regulator present or not in your Merc. outboard and the precautions that should be followed if you want to use your motor without a battery.
But how would I know?? I'm only a sparky and have no right to refer to the marvellous world of DC


Misinformation. I hate it and hate it with a passion.
Hopefully people will read this and realise they may not be up poo creek without a paddle if their battery is disconnected.
They my realise they may not be risking the destruction of their charging system if they run their motor without a battery.
People may realise they should be reading their particular manual and see what's what in regards to their motors and do not take what people say here as gospel.

[oldboot]

WARNING

Before operating engine with battery leads disconnected from battery. Disconnect stator leads (yellow) from the rectifier, insulate (tape) stator lead ring terminals.


If the above is not sufficient for you and you cant grasp the implications your english comprehension, understanging of electricity and diagnostic reasoning are poorer than I expected and you must be thick as 2 short planks.


But by now I have fugured that out anyway.


cheers

[BM]

How bout we agree that it's "Gulliper magic" under the flywheel or like in the etec DVD the pro Fisho Denny says "they've got magic under that hood"??

From my perspective I see both you guys arguing more or less the same thing from different ends and different angles. Pretty humorous actually. Quite a balanced level of insults either way ;D

I don't personally care whether there is a centre tap on the windings or not, nor do I care what peak voltages are produced. That info is good for designers to know but to the layman owner or the repairer but that knowledge is of no benefit.

There's some coils/windings under there that charge the battery via rectified AC and some coils that provide the power pack with it's initial voltage to pass on to the coil/s for amplification and firing duties

There's also some coils under there to control the firing of the power pack (in a diatributorless system).

Finga fire up the outboard of yours and take some voltages from the stator at various rpm. If you kill a reccy in the process I'll post you one.... ;D ;D

[oldboot]

The centre tapped coil is a significant issue, significantly when combined with low spec dark age diodes.

In a single coil with a single diode typical of Briggs and stratton motors...the issue does not occur. Because with the battery out of circuit and no accessories turned on the whole thing is open circuit.

in a single coil with a 4 diode full wave bridge (never seen one in a stationary motor or ouitboard, but anyway) the voltage across the rectifier with no load will be half that of a centre tapped configuration.

In the center tapped configuration the voltage across the reverse biased diode in the pair will be twice the voltage some may expect in the unloaded coil even before the open circuit voltage rise is considered..there lies part of the problem.

so if 22 volts DC has been measured on the output of the rectifier with the battery disconnected and the motor at low RPM.
At least 50 volts AC ( average) across the open ends of the centre tapped coil is certainly to be expected under the same circumstances.

We have not yet reved the motor which will significantly increase the voltage, and we have not allowed for an average to peak to peak conversion.
So a end to end voltage of well over 100 volts peak to peak at 5000 RPM is far from unexpected or unreasonable.

Combine that with a dark age spec diode with a PIV of under 100V, and you have a snotted rectifier.

That is the logic for those interested.

It would not be hard to completly illiminate the problem...simply by making rectifiers with something like 400V PIV diodes...perhaps some manufacturers do.... but there are still plenty of dark age spec rectifiers still out there..because for some manufacturers it is the same part made to the same spec since the 60's.


If I was a betting man..and I am not.......that motor that was measured....if it was 22 volts DC that was indicated on the meter at the output of the regulator relative to ground and that was at near idle.....I would not be surprised at all to see 150 to 200 Volts across that open circuit coil measured peak to peak at 5000 RPM.....I would be surprised to see 400V... but not greatly.

Anybody who wants to go and test it...knock yourself out.....I don't need to, because the manufacturers cautions and the enquiries I have made are enough for me.

cheers

cheers

[Bros]

From my perspective I see both you guys arguing more or less the same thing from different ends and different angles. Pretty humorous actually. Quite a balanced level of insults either way

In the Red corner we have nitpicker with prostate problems

In the Blue corner we have someone who doesn't know when he is being baited

and from the audience we have a parrot

The whole thing is hilarious

[mod2]

And this is where it ends. The personal jibes and going over the same ground does no one any good.