Fried My Alternator :(

[GrahamHO]

[QUOTE=Dockhead;1889217]Through a series of stupid mistakes, I seem to have fried my alternator

The first one occurred when I was anchoring near the Holtenau Lock of the Kiel Canal, last May. I forgot that I had some heavy loads on the inverter. The mud was soft and it took two attempt to get the hook set. The windlass was used a lot, and even the bow thruster. Simultaneously with the heavy inverter load this was too much, and something flipped off and the alternator stopped producing output. It stank of burning electrical parts, and the "no alternator output" light was lit up on the instrument board. I was too tired to try to fix it and went to bed. In the morning, it was working normally (which seemed miraculous to me), and it worked normally the rest of the summer.

Fast forward to today. I was motor-sailing in the North Sea and noticed the "no alternator output" light was on. Sure enough, no charge voltage. Looked in the engine room, and it was hot -- no engine room fblowers. Damn. This time there was no load of any significance on the system.

I spent a lot of time reading the wiring diagrams and tracing circuits, and came to the conclusion that the problem was a bad contact in the crappy Yanmar ignition switch. This switches on power which closes a relay which powers up the alternator exciter wire and also the engine room blowers. It looked to me like I just needed to get power onto that wire and I would have charging and blowers. It seemed to me that the simplest way to do this on a temporary basis would be to put the power onto the field post of the alternator.

So I made a jumper and did so, after checking and rechecking and measuring the voltage (not to confuse 12v with 24v).

As soon as the contact was made, the engine lugged as it usually does when the big Leece-Neville 110 amp (x 24v) school bus alternator starts up. I thought -- well, I figured that one out all right. Went around to the other side to check the engine room blowers -- yep, blowing away. But then I notice a cloud of acrid smoke. Quickly took the jumper off. Damn, damn, damn.

The solution to the problem is obvious -- take off the alternator and take it to an auto electric shop for repair. I'll do that when I get back to the UK.

But -- what did I do wrong? I have thought and thought about it, consulted Nigel Calder's book, and just can't figure it out. I'm sure it was something stupid, but it would be nice to know what.[/QUOTE

Did you get the polarity connection of the jumper lead correct. The wrong way can fry the diodes. A friend installed his battery with the wrong connections + and - and his alternator when off with a puff of smoke.
I took it to an alternator specialist for him but no replaceable parts and it was toast.

You shouldn't have had the original problem initially if all was correct. Maybe you need a big overload circuit breaker on the supply to your anchor winch. I have one and it has cut out when tightening a bow rope on a floating dock. No worries then and no overload.

[GILow]

Originally Posted by Ironman162

The whoke spares philosophy is an interesting one I for one one love having backups if backups and often have to stop myself from hording!

Out boat has come up more than 4 inches at the waterline since we bought her. The spares on board were truly an impressive collection. But as time progressed and I got to (partly) understanding the boat, I realised 90% (literally) were spares for devices that were no longer on the boat, and of the remaining 10%, more than half were ruined by age or moisture.

It was quite liberating to start from scratch.

If it helps anyone, my strategy, as yet untested by any serious sea miles, is to try to make everything as standard as possible (so engine hoses changed to standard car engine hoses from a common Australian car, alternator mount changed to take a very common Australian car alternator, exhaust system standardised to one size of exhaust hose, the FIVE different fan belt sizes now down to two sizes.. etc etc). Skin fittings standardised to one of two sizes. Cabin lighting standardised to one of two fitting types... and so on.

Our boat will never be light, but by golly it will be lighter than it was.

And, on a subsequent phone call with the original owner, when he suddenly confessed that he really felt he had overloaded the boat and I should try to get the weight back down again, I didn't have the heart to tell him I had already put everything in the rubbish skip at the yacht club, so I just agreed to do what I could.

Matt

[sartorst]

Originally Posted by sartorst

http://www.adverc.co.uk/cm/files/pdf...structions.pdf
page one near bottem yellow must be connected

disregard that, after reading more I was just looking at the circuit and making assumptions because many charge circuits will not charge without sensing the voltage drop from the bulb

[sartorst]

As we add more and more complications to our boats wiring we can inadvertently create monsters
as in my boat after a disconnect/replacement of all the battery's ( as in heading offshore ) on restart there would be no alternator output!! on 2nd restart everything ok????? drove me batty but just learned to accept it

[Dockhead]

Originally Posted by Oceanride007

Suggestion out of left field.

Its possible that the Fan motor had a fault and either blue a fuse or sank the voltage going to the alternator, meaning, the ignition wire is skinny and amp^2 times resistance made your field current go low.

Suggest you have blown the fan not the Alternator.

I've hot wired the blower since I really need when running either the main or gennie. It works fine.

But the thought is really useful anyway -- it's important to think of everything -- so thanks.

[Dockhead]

[QUOTE=GrahamHO;1890215]

Originally Posted by Dockhead

Through a series of stupid mistakes, I seem to have fried my alternator

The first one occurred when I was anchoring near the Holtenau Lock of the Kiel Canal, last May. I forgot that I had some heavy loads on the inverter. The mud was soft and it took two attempt to get the hook set. The windlass was used a lot, and even the bow thruster. Simultaneously with the heavy inverter load this was too much, and something flipped off and the alternator stopped producing output. It stank of burning electrical parts, and the "no alternator output" light was lit up on the instrument board. I was too tired to try to fix it and went to bed. In the morning, it was working normally (which seemed miraculous to me), and it worked normally the rest of the summer.

Fast forward to today. I was motor-sailing in the North Sea and noticed the "no alternator output" light was on. Sure enough, no charge voltage. Looked in the engine room, and it was hot -- no engine room fblowers. Damn. This time there was no load of any significance on the system.

I spent a lot of time reading the wiring diagrams and tracing circuits, and came to the conclusion that the problem was a bad contact in the crappy Yanmar ignition switch. This switches on power which closes a relay which powers up the alternator exciter wire and also the engine room blowers. It looked to me like I just needed to get power onto that wire and I would have charging and blowers. It seemed to me that the simplest way to do this on a temporary basis would be to put the power onto the field post of the alternator.

So I made a jumper and did so, after checking and rechecking and measuring the voltage (not to confuse 12v with 24v).

As soon as the contact was made, the engine lugged as it usually does when the big Leece-Neville 110 amp (x 24v) school bus alternator starts up. I thought -- well, I figured that one out all right. Went around to the other side to check the engine room blowers -- yep, blowing away. But then I notice a cloud of acrid smoke. Quickly took the jumper off. Damn, damn, damn.

The solution to the problem is obvious -- take off the alternator and take it to an auto electric shop for repair. I'll do that when I get back to the UK.

But -- what did I do wrong? I have thought and thought about it, consulted Nigel Calder's book, and just can't figure it out. I'm sure it was something stupid, but it would be nice to know what.[/QUOTE

Did you get the polarity connection of the jumper lead correct. The wrong way can fry the diodes. A friend installed his battery with the wrong connections + and - and his alternator when off with a puff of smoke.
I took it to an alternator specialist for him but no replaceable parts and it was toast.

You shouldn't have had the original problem initially if all was correct. Maybe you need a big overload circuit breaker on the supply to your anchor winch. I have one and it has cut out when tightening a bow rope on a floating dock. No worries then and no overload.

I worried about that, but I have verified that my jumper was correctly wired.

I took that lead off the alternator, and put power onto it, in order to get the blowers working. It worked perfectly and in fact is working right now as I speak while I do a load of clothes with the genset running.

So I think so far there are only two plausible theories --

1. Alternator was already on its last legs and was just finished off by that last load up.

2. Adverc malfunctioned.


I still have one on-boat test to do: Disconnect the Adverc, reconnect the D+ leads on the alternator, start it up and see if it charges using the original regulator.


The blower is an interesting sign. The fact that the blowers went out at the same time that the alternator stopped charging seems to show that there is an internal short in the alternator (or in the Adverc) which popped a fuse or blew out the relay under the helm and stopped the power to D+, thus stopping power to the blower relay.

I will also have a look under the helm when I have a chance.

Thanks to everyone for all the interesting thoughts.

[blackswan555]

Just to confirm my correct reading of description, You basically took a live feed from bat +, joined that to blower feed & alt D+ ?
If above is correct ? I will take a guess, D+ is Neutral when alternator is not charging, Usually through a light to ignition switched live, Then when alternator starts charging, It becomes live, using usually it's own small diode bank,
When you connected a direct Bat + to D+ initially it popped theses diodes, On starting this caused either a diode to earth short or a full/overload charge situation due to the reg having no voltage sense
Your diode train is almost definitely dead, But with a bit of luck it failed first


Tim

[NakedCity]

Tickler wiring is causing your problem, you have probably fried the diodes in your alternator. When the tickler is powered thru the ignition switch the power is routed thru maybe a panel bulb or in some cases an oil pressure switch which will prevent current from backfeeding thru the tickler back into your alternator.
You need to either repair and restore the original wiring or go to an alternator shop and they will give you a diode to install in the tickler wire to prevent this from happening.
GOOD LUCK

[Nicholson58]

Originally Posted by Dockhead

But -- what did I do wrong? I have thought and thought about it, consulted Nigel Calder's book, and just can't figure it out. I'm sure it was something stupid, but it would be nice to know what.

Hard to say. We have had two alt failures. Both following lightning hits. Both times several diodes in the Alt were fried. The second time, it was a total wipe out. With no diodes, the Alt passes massive current and might heat up to several hundred degrees before the final disaster. Fortunately, I caught it and pulled the cable at the shunt. Re-build at my favorite Alt shop is about 60 bucks including parts & labor. You can buy diode repair kits.

[chala]

Originally Posted by Dockhead

But -- what did I do wrong? I have thought and thought about it, consulted Nigel Calder's book, and just can't figure it out. I'm sure it was something stupid, but it would be nice to know what.

For one, you should not have

Originally Posted by Dockhead

made a jumper

Without including in the jumper the lamp “IGN W/lamp” as per yours drawing or a suitable resistor. For 12V a 47R is suitable. Check with manufacturer.

For two, jumping the terminals with the alternator running.

[Dsanduril]

Dockhead's misfortune has been fascinating (sorry Dockhead) as I have done the same full-field testing (and operation) any number of times with no ill effects. But the Bosch style seems to be a little different than what I am used to, so it's taken a little reading. Found this to be the most comprehensible explanation:

Pelican Technical Article: Alternator System Troubleshooting

There are four connections to the alternator itself. D+, DF,D-, and B+. If you look at the Haynes book, 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. The lower set of diodes on current track 80 is common to both the D+ and B+ functions, and forms the ground return for both the B+ and D+ outputs. The DF or "Dynamo Field" terminal connects to the ungrounded end of the alternator field winding, and is an input to the alternator. The current supplied to the DF terminal determines the strength of the magnetic field that penetrates the output windings, and thus controls the alternator's output. The D- terminal is connected to the alternator frame, and is the ground return for the voltage regulator. The other end of the field winding is also connected to ground at this point.
The Bosch alternator is incapable of self-excitation, or "boot-strapping" itself to an operating condition. Older DC generators and some U.S. alternators have residual magnetism retained in the core, or some other scheme to get enough field current to get themselves up and running. The Bosch alternator uses a different scheme. The charge warning lamp is connected between the ignition switch and the D+ terminal. When the car is first started, there is no output from the alternator at either the B+ or D+ terminals. The voltage regulator, sensing no output, is attempting to command maximum field current... it effectively shorts the D+ and DF terminals together. This places the D+ terminal close to ground potential, because the resistance of the field winding is not large. This means that there is +12 volts on one side of the charge warning lamp, and the other side of the lamp is grounded through the alternator field winding. Current thus flows through the lamp, lighting it. This same current, however, also flows through the alternator field winding, producing a magnetic field. This magnetic field is what the alternator needs to start up, and if everything is working correctly, that's exactly what happens. The alternator now begins to develop identical voltages at the D+ and B+ terminals. The D+ terminal is connected to one end of the charge warning lamp, while the other end of the lamp is connected to the battery via the ignition switch. Since the B+ terminal is hard-wired to the battery, and since both the D+ and B+ diodes are fed from the same set of windings in the alternator, no voltage difference can exist between these two points. The warning lamp goes out.

The voltage regulator "watches" the voltage at the D+ point, which should be the same as that applied to the battery. It now changes the short between the D+ and DF terminals into a variable resistance. This effectively controls the field current (whose source is now the output from the D+ terminal, and not the charge warning lamp) and thus regulates the output voltage of the alternator.

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

[Dockhead]

Originally Posted by chala

For one, you should not have



Without including in the jumper the lamp “IGN W/lamp” as per yours drawing or a suitable resistor. For 12V a 47R is suitable. Check with manufacturer.

For two, jumping the terminals with the alternator running.

Thanks, sounds right to me.

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

[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

[Dsanduril]

I don't see it. Why would a direct live to the D+ pop any diodes? That terminal is intended to be +, the light only offers a "soft-start" to the alternator by limiting the available field current until the regulator takes over. By having a voltage connected to D+ directly you are certainly slamming the alternator into full operation instantly, but as D+ normally operates at B+ voltage, so having the direct lead isn't any different than normal operation.

You are operating on the output side of the rectifier diodes, and not shorting any of them (the maximum current you can flow is limited by the rotor resistance - in a 12V alternator that is usually 2.4Ω and limits field current flow to 6A). The reason the lamp works is because without the alternator running there is only 2.4Ω to negative through the rotor coil, but that same 2.4Ω limits any current fed to D+.

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

[esarratt]

Wow! I'd let that one go. I was surprised while reading that you had the knowledge and patience to investigate and do what you did. Alternators aren't THAT expensive. Giving yourself a hard time for doing the best you knew how to do is. I really would let that one go.

Just my thoughts.