Generator Help

We have been traveling south on ICW for 5 days now, up until yesterday generator has worked flawless, zero issues or complaints.


Yesterday after unhooking shore power, noticed we weren't getting full load out of generator. Runs great engine wise, just not producing enough power, just under 50 volts, see pic (know how yall love pics).


Have checked every fuse I can find, flipped and refliped every breaker multiple times. Part of me feels like it's something stupid, cuz it's worked flawless up until it didn't. Part of me wonders if the power generation part of generator is just old and not getting it done (40 years old) and age got the best of it.


Looking for suggestions on what yall think it could be?

Different generators, especially of different vintages, can work very differently in ways that can impact how to diagnose something like this.

When one gets 50v like this, which is very low, but not ~5v low, my first thought is that a load surge took out one of the rotating rectifier diodes and a leg might be missing. If the generator is new, or newly rebuilt, my next thought is that there could be a bad solder joint.

After that, a problem with excitation or something going wrong with voltage regulation come to mind. In some cases there is a regulator board, in other cases, it can be a simple as mostly a capacitor. Capacitors sometimes bite the dust as the result of a load surge and/or age.

But, this all may be gibberish depending upon what generator you've got. If you can post the make and model, I and/or others may be able to see if we can find the schematics for it and offer better guesses.

It's a 15KW Westerbeke

Sounds like the electrical end has a problem, as mentioned above. If it is something like a rectifier/solder joint, a knowledgeable guy might be able to pop the end off where that item is and get you fixed up. If somebody tells you the windings are bad and the whole electrical end need to come out for rewinding, get a second opinion before going any farther. Good luck, and I hope it turns out to be easier than harder to fix.

Is it a 15WMD or a 15BTD? At 40yr old, probably a W, which is a round-ish Winco generator. That one has brushes and I think a square full wave bridge rectifier under the end bell, easy to get to. Check the brushes and test the rectifier. The rectifier is part of the exciting system. No other voltage regulator on these. Field winding is the stator, rotor is volts out, different from most.

Verify the panel voltmeter with a DVM or a Kill-A-Watt. Does the voltage return to normal when plugged into shorepower? If that checks out check the output at the generator output breaker and also the input to the output breaker. If low at the breaker input then gen end/voltage regulator problem.
Also the last thing you changed was the swap over from shore power to genny. Makes me suspect the transfer switch might be involved.

I have not taken multi-meter out yet, engine room been too hot after running all day to hang out in, but everything goes back to normal on shore power, that why my suspicion is generator.

Yeah. That looks old school. If it isn't one of the rectifier diodes or an obvious broken solder joint or connection, you might have to dig in. Maybe a brush wire.

Just for a sanity check, it does it whether loaded or unloaded, right?

I thought I knew a few things but reding the answers from people who know geerators is like reading Greek.

Glad we have such experts here.

pete

I do not think this is what is going on here, but I once had my 7.5 KW Onan MDJE quit making electricity while the engine ran ok. Come to find out, we reenergized the circuits after having it shut down in a lock with too many items turned on. The overload heated up the major cables in the control box which governed whether the unit produced 120 or 240 volts, and they burned apart where they had been joined in what I think was a less than effective manner many years prior. I rejoined them in a very beefy manner, and all was well. I suppose that if their ends have not burned apart that I would have been getting partial voltage like the OP is getting. It is worth a quick check.

I'm open to try anything! I do agree it seems odd, everything worked flawless till it didn't, my gut tells me it's something stupid going on.



We made it to Myrtle Beach, going to park here for a bit. Flying back home tomorrow, will come back in a couple weeks and dig into this more.

Since it’s making 50v , I believe the winding would not be shorted. They usually go down to 4-5 v. Slip rings come to mind , brushes, and the back of the brush holders should be inspected.

I have a 7.7kw Westerbeke. One day, it popped the 60-amp circuit breaker. I reset it. Twenty minutes later it popped again. This time I happened to touch the metal Square D breaker box. It was almost to hot to touch. Removing the control box lid revealed a truly hokey connection of the two wires leading from the brushes to the one feed wire to the circuit beaker. Ring terminals with a short nut and bolt all taped up. When I removed the tape I found the brush wires to be corroded and brittle from heat. Later inspection found those wires fully compromised all the way back to the brushes. I replaced those wires and ran them to a newly-installed busbar mounted inside the control box. No more fire danger

I am far from an expert on generators so here is a question for the experts. If one of the wires from the brushes is faulty, wouldn't this result in low voltage?

years ago we had a similar experience with 4.2 Entec. we had left dock with the air conditioner breaker on. when we started the genset on anchor the ac load blew one of the diodes. i had to pull electric end off and unsolder then resolder in a new diode. we were getting about 100v though.

Does the generator sound like it is running at the normal rpm? I know mine must run at 1800 rpm to give the correct voltage.

@Russell- Yeah, everything sounds normal, starts normal, runs normal, just not putting out full power.

Russell Clifton said:

Does the generator sound like it is running at the normal rpm? I know mine must run at 1800 rpm to give the correct voltage.

Click to expand...

1800 is the common rpm but that governs frequency. To have 60 hz, the rpm must be a multiple of 60. 50 hz, a multiple of 50. Then there are the number of poles, but that gets into a lot of theory....

FYI to all, I just had generator start issues. Would not start, no clicking, anything, even though the battery was good. Thinking it was either the starter or the starter solenoid, I procrastinated (contort self, put arm in position that it should not be in, hope wrench does not slip from hand, etc.) and started tracing wires. The secondary wire from the solenoid ran to a fuse. Instead of checking continuity through the fuse, I checked voltage on each side. One side was lower. Pulled fuse, cleaned it, replaced, and generator started.

What Irish Lady said…

As suggested, check the volt meter on the panel. I fixed a similar problem by taping on the face of the meter.

Check each leg of the gen unit with a meter and see what it is putting out… if all good then look at the rectifier for issues, or the voltage regulator unit.

I would suspect the latter over everything else first. Sometimes you just need to turn the pots up and down with a screwdriver and readjust to clean the wiper in the pots.

Check that you are making full 1800 rpm. Make certain that the fuel run solenoid is completely bottomed out. You can manually pull it in while engine is running.. check the on-engine circuit breaker is fully clicked in. Tiny red button on my 8 kw westerbeke. Check that the secondary fuel filter is not clogged, and restricting rpm. Good luck.

I had a similar problem. Factory rep said I needed a powerhead rebuild. I got a second opinion. It turned out a $0.05 connector was broken. Carefully inspect the powerhead.

I hope you’ve been able to rectify your issue easily (no pun intended). I’ve worked with two friends that have had similar issues on Westerbekes.

After trying a couple of so called generator techs to diagnose issues (lots of head scratching, but no real result), the first was resolved with a swap out of the alternator back end, (not an inexpensive option).

With the second, we found a local specialist motor rewind service who reckoned there wasn’t a generator he couldn’t fix. It proved a tall order for him but 2.5 months later, he managed to get it rewound and working, spending much more time than he charged.

Westerbeke alternator winding, exciters etc aren’t conventional and some WB tech experience is needed otherwise you’ll pay for hours of learning while they try to figure things out.

All the local Westerbeke agent wanted to do was to sell a complete back end, and reaching out to US Westerbeke support for information was like breaking into Fort Knox, with them not wanting to divulge proprietary information. He finally managed to get some help on rewinding/wiring specs etc from a European motor winding tech to allow him to complete the job. (I don’t think he’ll repeat the exercise however).

From memory a while back, there was one company on the east coast near the bottom of the ICW Broward Electrics, who could supply a backend changeover. Not sure whether they have them or still do it, but I’d suggest you Google Westerbeke alternator replacement or repairs and see what pops up, or call them directly.

Good luck with it. Cheers

Wanted to follow up on this, and yet again seek help from the Jedi Masters.

Reached out to Westerbeke, spoke with their guru, guy named Tom Camara, who was super helpful, and really about a nicest/helpful guy you would ever want to speak to over the phone from a manufacture standpoint. He walked me through all the trouble shooting steps, sent me pdf manuals, etc.

Also was able to find a local mechanic in Myrtle Beach area who is a Westerbeke guru. Was able to get local guru to come spend 2 hours trouble shooting generator. Together we went through everything either of us could think of.

Local mechanic guru says he does not think its windings/stator or anything on generator unit itself. We also tested the 12v system, which has alternator on engine, all is well there.

We put volt meter on just about everything there is to test, best guess is the Printed Circuit Board has and issues somewhere on it. Keep in mind this is 41+ year old circuit board.

Will call Westerbeke on Monday to see if they have a replacement circuit board, but have my doubts. When I was speaking with their guru he straight up said he was not sure they had any parts for my generator outside of basic stuff.

So am asking if anyone here has any idea's on where to procure a replacement circuit board? Going to also call Broward Electrics down in Florida for help.

Generator is a Westerbeke 40-WPDS 15kw (YD version) built in 1980

The first thing to do is remove the board from the mounts. Then carefully look on the underside for hot spots

Arc said:

The first thing to do is remove the board from the mounts. Then carefully look on the underside for hot spots

Click to expand...

agreed. that board is mostly just a collection of resistors, a couple of diodes, and what looks like a pair of triacs? ohm out the resistors, replace the diodes and triacs. worth a try and only a few bucks worth of parts. maybe re-flow the solder joints if they look iffy.

Got Lucky! Westerbeke had a new circuit board in stock, guess the technical term is regulator board, $985 later new board is on the way to Myrtle Beach. The same guy who was so helpful @ Westerbeke, pointed me to the page in the technical manual that has all the necessary info to completely rebuild the board, all the resistors, capacitors, etc. specs.

If anyone happens to stumble onto this thread later, need to get their board rebuilt or make one from scratch, all the info for the values for the parts to buy to do it are in the Tech Manual page T.47

I hope it fixes your problem.