Fried My Alternator :(

[sailnow2011]

We have our main 110amp (12v) alternator driven by a balmar 612, a second 612, and a internal regulated alternator in our spares. All of this on top of two battery chargers and a generator. We like power

[sy_gilana]

Hey Dockhead....

There is a company in .DE called Hueco
Hüco Online Katalog Automotive
They will carry a spare rotor, it sounds to me like your rotor is fried.
Its not difficult to put in a new rotor, (field) but it is difficult to rewind one, the insulation gets scratched as you pass the claws. In manufacture the two claw halves are pressed onto a pre-wound bobbin.

I have rewound my own stators, its much easier (pictures at my web page in the signature, click the 2012 button)

FWIW I have a 24v pos ADVERC that is not in use if you would like it.

I bought a few external regulators from Hueco, I suggest their 13 0319 model which is 28V adjustable 27-32V

You can change your alternator to be pos regulated or neg regulated easily.

One often ignored fact about alternators is the cooling. The fanblades are right or left handed. They must be reverse curved when spinning on your installation. If they are the other way the alt will overheat. Also the pulley must be sized to have the alt running "on its curve" ie. You should not pull high loads while it is spinning too slowly.

Allow me to explain the last sentence. An alternator is a machine that takes a little electricity and adds kinetic energy supplied by the engine, multiplying the power. In order to get a lot of power you can spin it really fast, this allows minor amounts of input (field) to have big outputs (B+)
BUT
If you are turning it too slowly, and your external regulator says GIMME!!!
The regulator makes the "decision" to increase the field to make a bigger magnet, and excess heat is generated.

I think the only way to find out what happened to yours is a forensic diagnosis after dis-assembly.

Hueco stock rotors, bearings, diode packs, regulators, everything...and the prices are realistic, eg. 12 euros for a diode pack.

Picture below is one of my two rewound alternators, this is a CAV 28/35, picture taken after completing 2nd phase.

[zeehag]

dockhead, have you learned nothing from me??? even i has a spare alternator now. i carry a spare starter and spare alternator, as these have tendencies to blow up or cease function at the worst ever times.
i also learned that when i buy a new item, keep the old for spares, as that old one was dynamite and irreplaceable. so i had starters rebuilt here in mexico, even allegedly un-rebuildable ones... and i am a happy camper.
they rebuild alternators also.
and someone nice decided i needed a regulator, so that has been installed as well. (learned these good things when i drove and repaired my volkswagens for many years.)
no i have no pretty pix as do you.

[Dockhead]

Originally Posted by zeehag

dockhead, have you learned nothing from me??? even i has a spare alternator now. i carry a spare starter and spare alternator, as these have tendencies to blow up or cease function at the worst ever times.
i also learned that when i buy a new item, keep the old for spares, as that old one was dynamite and irreplaceable. so i had starters rebuilt here in mexico, even allegedly un-rebuildable ones... and i am a happy camper.
they rebuild alternators also.
and someone nice decided i needed a regulator, so that has been installed as well. (learned these good things when i drove and repaired my volkswagens for many years.)
no i have no pretty pix as do you.

Well, my analysis of this question is above.

I have TWO alternators -- one standard 12v Hitachi which lives a life of leisure doing nothing but keeping the start battery charged.

The other is a hot-rated heavy duty 24v alternator for producing bulk power.

Both alternators are in service doing what they were designed to do, so are very reliable. When you take a car-type alternator (like my Hitachi) and try to get bulk power out of it, as many do -- in that case you can expect it to blow up regularly and you will need a spare on board. But I don't feel the need for a spare alternator on my boat. I have alternate sources of power for both systems -- in case the Hitachi ever went down, I can charge the start battery from the generator, from the 24v alternator and inverter, or even from the house bank, through a separate battery charger on that circuit.

For the house bank, I can use the generator as the alternate source of power, as I am doing now.

[zeehag]

doskhead, so far knocking wood, so goood--i d onot know source of my current alternator, but it has functioned well for over 10 yrs. has been painted somany times it is of uncertain origins. is why i was gifted a second one, just in case. i think sometimes that my just having the spare has kept the old one from blowing up....
mebbe i shoulda had a spare engine......

[GrahamHO]

Originally Posted by sailnow2011

We have our main 110amp (12v) alternator driven by a balmar 612, a second 612, and a internal regulated alternator in our spares. All of this on top of two battery chargers and a generator. We like power

You could just use your diesel as a generator and have electric motor drive.

[chala]

Originally Posted by Dockhead

Thanks, sounds right to me.

Why is the resister needed? Can you explain what it does here?

For one

Originally Posted by blackswan555

The resistor could replace a lamp, You need "something" in the D+ line as it becomes earth when alt is not running, Put a direct live to it and it errr,, Pops the diodes :
Tim

For two

Originally Posted by Dsanduril

Pelican Technical Article: Alternator System Troubleshooting

Quote
what is not readily apparent, but is true nevertheless, is that the set of diodes that connect to the D+ terminal are a duplicate set (except for lower curent rating) to the ones for the B+ terminal, which is the actual high current output of the alternator. The D+ terminal is therefore a duplicate output terminal of the alternator, with less current capability.
End of quote

Just passing it on as others may find it interesting as well.

It is likely that “the set of diodes that connect to the D+ terminal” did carry through the jumper “the actual high current output of the alternator” due to a failure (bad connections, failure of the main diodes) of the B+ circuit.

Originally Posted by Dsanduril

It's a pretty standard test to full-field an alternator for a short time. Running it that way...

I do not see what that test achieve if it is the possibility of damaging “the set of diodes that connect to the D+ terminal” but

Originally Posted by chala

then enjoy.

I try to repair it my-self, if lucky you only have some diodes to replace.

[chala]

Originally Posted by blackswan555

The resistor could replace a lamp,

Also wired in parallel with the lamp, the resistor will keep the system operational in the case where the globe, in the lamp, was to fail.

[chouliha]

Originally Posted by GILow

On our delivery trip home the biggest single time waster was the alternator that stopped working just 36 hours into the trip. I fretted over avoiding this issue for a year before deciding to fit one good quality alternator with a spare basic (cheap) model carried on board in an air tight bag. The trick was to ensure they could be easily swapped. Got there in the end but the solution involved a bit of farting around with the welder to make a reasonably universal mounting bracket.


Sent from my iPad using Cruisers Sailing Forum

Our approach is very similar. the main concern is offshore and experiencing an alternator failure I don't want to be trying to rebuild the darn thing underway with tools and stuff flying around. So we have an exact drop in as a spare. Yep more $$ but much easier in the long run for me. I hate to do repairs at sea and try to make it as easy as possible. We also have a rebuild kit as well since just about any place of decent size can rebuild an alternator. Having the spares in hand makes it very doable.

My other thought is I agree with a previous poster that damage had been already done to the unit before hand. I always worry about those things that fix themselves. HaHa it keeps me awake at night

Good luck with the repair. Let us know what you discover.

Chuck






www.jacarandajourney.com

[Dockhead]

I have received my alternator back after being rebuilt with a new stator and windings.

I was concerned about lifting the heavy thing into place and getting the pivot bolt into it, but I used the same rope hanger which I made up to get it out, and it was a cinch. I was able to squeeze the two legs of the hanger together with my left hand and finely regulate the height of it, and was able to just pop the bolt in with my right hand. Gratifying when a mechanical job turns out to be easier than expected, for a change.

But the alternator produces no power

With the engine running, I have system voltage (25 volts) on the exciter terminal, and 21.7 volts on the stator terminal. The "alternator not charging" light does not glow. But there is zero output, measured with a clamp meter, and also judging by voltage drop when loads are put on.

Connections are all good (checked carefully before initial startup).

So what gives? I presume that the people who rebuilt it simply botched something, which means I will have to pull it out again and ship it back to them , but is there anything else to check before doing so?

[Snowpetrel]

External regulator is working?

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[Oceanride007]

No Power! Do you mean you have voltage but no Amps? Sounds like you are disconnected from your battery.

No Voltage ahh. Gets complicated. Any chance of getting repairer to attend. If not ask them for basic tests that you could do, insitu.

[Dockhead]

Originally Posted by Snowpetrel

External regulator is working?

Sent from my HTC_0PCV2 using Cruisers Sailing Forum mobile app

I have an Adverc which, if disconnected, lets the alternator revert to the internal regulator.

Both connected and disconnected -- same result

So highly unlikely to be the regulator -- would have to be a freak simultaneous failure of both.

Anyway, there are 25 volts on the exciter terminal -- doesn't that mean that the regulator is giving the signal to make power?

[Dockhead]

Originally Posted by Oceanride007

No Power! Do you mean you have voltage but no Amps? Sounds like you are disconnected from your battery.

No Voltage ahh. Gets complicated. Any chance of getting repairer to attend. If not ask them for basic tests that you could do, insitu.

There are volts on the output terminal -- system voltage, from the batteries. This is the same whether the engine is running or not. I checked this connection before initial startup in order to be sure not to blow the diodes.

Voltage does not increase when the engine is started and sags when load is put on.

And no amps coming out of the alternator.

[Oceanride007]

From left field, Diodes in backwards, Field winding reversed.