Westerbeke generator question

[seattleboatguy]

I have a Westerbeke 4.4 kw generator with 500 hours that came with the 1987 Marine Trader 38 I purchased a couple years ago. This week, it decided to only generate 2.6 volts instead of 115 volts. The generator engine looks and runs fine. My questions are:

• Should I be looking for a generator electrician or a boat electrician or a Westerbeke electrician?
• Will the electrician unbolt the back end of the generator and take it to his shop, or is he going to want the whole engine pulled out of the boat?
• Is it significant that there is a placard on the generator that says it was rewound by Broward Armature in Ft Lauderdale?

 

[High Wire]

Call Broward Armature

 

[Dwk]

Only the back end of generator may have to be removed for service not the entire unit with engine

 

[kev_rm]

I have that vintage 8kw WB and the manual to go with it... there are exactly zero pages in the manual dedicated to troubleshooting the generator end of the unit.. Not much to go wrong there.. 2.6v probably means zero when measuring AC.. double check your panel maybe?

Also, peanut gallery comment: You should use phase tape on your cables if you like black so much.

 

[seattleboatguy]

there are exactly zero pages in the manual dedicated to troubleshooting the generator end of the unit.

I noticed the same thing in my manual. Seems crazy. Maybe the AC power generation stuff is just too complicated and/or dangerous to tinker with.

 

[seattleboatguy]

Only the back end of generator may have to be removed for service not the entire unit with engine

Well, that is encouraging.

 

[twistedtree]

I'd get a generator guy to look at it. It's much more likely to be something simple with n generator end removal required.

 

[Alabama Boater]

From the photo posted of the winding end, it appears to be a capacitor regulated output. If cap failed there will be no AC voltage. The bridge rectifier, to the right of the capacitor, could also be an issue. On my Westerbeke 8KW, I had half of the bridge out and as I added load, voltage dropped way down. If both sides of rectifier are out, no AC output. The cap and rectifier are easy to verify with a multi meter, without major disassembly. I was able to find a .pdf service manual copy for mine on line.

 

[Ski in NC]

Check capacitor. Rectifier is just for batt charging on this, not part of AC circuit. Broward rewinds have a good reputation, worth a call to them.

How long ago did it make good power? If a long time, residual magnetism may have decayed and it could use a reflash.

 

[what_barnacles]

check and see if it makes 115 while you are pushing the start button or at least a lot more than the 2.5. If so then the control components are the problem.

It may be just be a relay or a diode or even brushes.

 

[Daddyo]

I sent my WB 7.7kw to Broward several years ago for a rewind and it's run great since.

 

[seattleboatguy]

I sent my WB 7.7kw to Broward several years ago for a rewind and it's run great since.

Did you somehow unbolt the "electrical end" of the generator and ship it via UPS, or did you have to give the whole generator to some shipping company?

 

[DavidM]

seattleboatguy:

Before you even think about removing and shipping to Broward, check or replace your capacitor. Most are 40 mfd and Amazon has them for less than $10.

To check, disconnect the wires and hook up an analogue ohmmeter set to low range to the terminals. The resistance should start out low and then slowly rise as the capacitor charges to the meter's resistance sensing voltage. If it is immediately high, it is bad.

These fail routinely on marine generators due to heat. So if you have that kind of capacitor excitation, and it looks like you do, then 99% of the time a bad capacitor is what causes no ouput voltage.

David

 

[bikeandboat]

No idea how to repair the generator, but I had the very same model for a few years. I found it to be a real workhorse. Stay with it if you can.

 

[what_barnacles]

I noticed the same thing in my manual. Seems crazy. Maybe the AC power generation stuff is just too complicated and/or dangerous to tinker with.

By the way you have to go on westerbekes website to get the proper tech manual. This is the 4.4bcd's... It has everything you need.

http://www.westerbeke.com/technical%20manual/43444_rev1_w13-35b_wmd4.4-10btd_technical_man.pdf

if yours isnt a bcd then look down under "older models"
Diesel Generators - Westerbeke

 

[kev_rm]

seattleboatguy:

Before you even think about removing and shipping to Broward, check or replace your capacitor. Most are 40 mfd and Amazon has them for less than $10.

To check, disconnect the wires and hook up an analogue ohmmeter set to low range to the terminals. The resistance should start out low and then slowly rise as the capacitor charges to the meter's resistance sensing voltage. If it is immediately high, it is bad.

These fail routinely on marine generators due to heat. So if you have that kind of capacitor excitation, and it looks like you do, then 99% of the time a bad capacitor is what causes no ouput voltage.

David

Might also want to discharge (short) cap first and also digital vm's have worked for me on this test.

 

[seattleboatguy]

seattleboatguy:

Before you even think about removing and shipping to Broward, check or replace your capacitor. Most are 40 mfd and Amazon has them for less than $10.

To check, disconnect the wires and hook up an analogue ohmmeter set to low range to the terminals. The resistance should start out low and then slowly rise as the capacitor charges to the meter's resistance sensing voltage. If it is immediately high, it is bad.

These fail routinely on marine generators due to heat. So if you have that kind of capacitor excitation, and it looks like you do, then 99% of the time a bad capacitor is what causes no ouput voltage.

David

That sounds like something even I could do. I'll give it a shot. Thanks very much.

 

[seattleboatguy]

No idea how to repair the generator, but I had the very same model for a few years. I found it to be a real workhorse. Stay with it if you can.

Good to know. I'll do my best to get it fixed. Thanks.

 

[seattleboatguy]

By the way you have to go on westerbekes website to get the proper tech manual. This is the 4.4bcd's... It has everything you need.

Your link to the service manual is fantastic! That should prove very useful to either me or (if necessary) the repair guy. Thanks very much.

 

[seattleboatguy]

Might also want to discharge (short) cap first and also digital vm's have worked for me on this test.

Understood. I will also be using a digital meter, but I think that will tell me what I need to know. Thanks very much.

 

[DavidM]

He suggested shorting the cap before doing the test for two reasons: It can give you quite a shock if it really works if you have just shut the genset down; it can also blow your meter if you don't first discharge it.

I have never tried this test with a digital meter. These use a very low voltage to measure ohms, so it may take a while to build up a charge on the capacitor to show the resstance dropping. I also like to see things change in analogue form rather than chase digits bouncng around and maybe even autoranging confusing things.

But give it a try.

David

 

[Ski in NC]

No worries about discharging cap. Winding loop it is attached to is a dead short with machine off.

Some mid range up DVM's have a microfarad setting for testing caps.

With clever use of ohm or volt setting with a chargeup, you can establish whether it has some capacitor function, but it will not be easy to test conclusively.

And it could just need a flash.

 

[what_barnacles]

Could just need a flash???

 

[BruceK]

Could just need a flash???

Should be easy, some marinas have a resident flasher, ours does, late at night.

 

[Egregious]

Your link to the service manual is fantastic! That should prove very useful to either me or (if necessary) the repair guy. Thanks very much.

Call Westerbeke ((800) 548-6252 ). They are very helpful and you'll get a human being after a few rings. They're used to dealing with the old models. They also have any parts, except for injector pipes, but you can have one of those fabricated at any injector shop.

 

[seattleboatguy]

Call Westerbeke ((800) 548-6252 ). They are very helpful and you'll get a human being after a few rings. They're used to dealing with the old models. They also have any parts, except for injector pipes, but you can have one of those fabricated at any injector shop.

Good idea. Couldn't hurt. Thanks!

 

[seattleboatguy]

seattleboatguy:

Before you even think about removing and shipping to Broward, check or replace your capacitor. Most are 40 mfd and Amazon has them for less than $10.

To check, disconnect the wires and hook up an analogue ohmmeter set to low range to the terminals. The resistance should start out low and then slowly rise as the capacitor charges to the meter's resistance sensing voltage. If it is immediately high, it is bad.

These fail routinely on marine generators due to heat. So if you have that kind of capacitor excitation, and it looks like you do, then 99% of the time a bad capacitor is what causes no ouput voltage.

David

Hi David. I did the test you suggested, made a video while the test was running, then loaded the first 30 seconds of test results into a spreadsheet. Each second, I was able to record 2 or 3 readings from the multimeter. The multimeter was set on "2K" of the "OHM" scale. Before I hit the generator start button, the multimeter read .001 . After I hit the start button, the multimeter readings bounced around quite a bit between -.364 and +1. The test result data is shown below. I could see no clear trend in the data. Does this mean the capacitor is shot?

http://www.seattleboatguy.com/tmp/2017-02-22_a.jpg

http://www.seattleboatguy.com/tmp/2017-02-22_b.jpg

 

[High Wire]

Picture don't work for me. Go to YouTube and search "testing capacitors " watch at least five different videos and you will get the point.

 

[twistedtree]

Hi David. I did the test you suggested, made a video while the test was running, then loaded the first 30 seconds of test results into a spreadsheet. Each second, I was able to record 2 or 3 readings from the multimeter. The multimeter was set on "2K" of the "OHM" scale. Before I hit the generator start button, the multimeter read .001 . After I hit the start button, the multimeter readings bounced around quite a bit between -.364 and +1. The test result data is shown below. I could see no clear trend in the data. Does this mean the capacitor is shot?

http://www.seattleboatguy.com/tmp/2017-02-22_a.jpg

http://www.seattleboatguy.com/tmp/2017-02-22_b.jpg

I don't think you did the test correctly. It's done with the generator off, and the capacitor disconnected. Only the meter probes should be on the capacitor.

 

[DavidM]

Twistedtree is correct. Read my original post. You remove the wires from the capacitor, hook up an ohmeter to the BARE terminals and read the resistance. It should start low and build up as it charges the capacitor. If it starts high and stays high, then it is shot.

I will admit, it is a subjective test and a lot depends on the characteristics of the ohmeter, but if the resistance starts low and rises, it is probably good.

But it is cheap. Just replace it for $10 if you are not sure.

David