Wild Westerbeke issue

T

Theresamarie11

New Member
Aug 18, 2009
365
Vermont
Boat Info
2002 Sundancer 300
Engines
Twin 350 Mag, Westerbeke Genset
Hi, just purchased a fully surveyed 300 DA with a few problems not uncovered. One is with the Westerbeke 4.5 kw generator.

The westerbeke motor and cooling system run fine. What doesn't (at least initially) is the output AC voltage.

When I start it up, the output voltage is around 25V and seems like it'll stay there all day if I just left it. So I called the prior owner and he said to get it up to voltage I needed to add the water heater load...and wait a bit. So I did that (no change) it just stayed there.
But, since I had saw it running when I purchased it, I fooled around and added/disconnected all of the loads and as I did this, each time the AC voltage would bump up a bit. So I'd disconnect all loads with the master switch, then turn the master back on and add all the loads. Each time I did this the voltage would go up another 10V or so (from the last point) until when it got up around 90V and then when I added loads it jumped up to 120 and ran for 8 hours just fine.


Any ideas?

Thanks,
Terri
 
Capacitor.
 
fc3 said:
Capacitor.
Click to expand...


Thank you Frank and Tom.. I assume this is the exciter circuit capacitor? The big 25uf or 31uf cap? I opened the side panel after downloading the troubleshooting document to my ipad on the boat and the capacitor was one of the items suggested. Unfortunately I didn't have a multimeter on board so I had to leave it for later. I'll just go order the capacitor. Thanks guys.


Terri
 
That's the one.

If you search the net for digital multimeters, you can find a lot of decent cheap ones for sale. Recommend having on aboard.

Best regards,
Frank
 
fc3 said:
That's the one.

If you search the net for digital multimeters, you can find a lot of decent cheap ones for sale. Recommend having on aboard.

Best regards,
Frank
Click to expand...

You can get one for about $3 at Harbor Frieght...
 
Get a DVOM that reads fequency,I needed that to set the generator to 60 cycles( not sure if your model requires it).I picked a nice one up at Lowes,around $35.
 
Ok Guys, I removed the old cap and it read low (22uf) versus spec of 31.5uf, but, when I put the new cap in (28uf measured) it works even worse and will not come up to full voltage at all.
I am now thinking one of the diodes is shorted. I'm going to unsolder the exciter windings on the armature and check the diodes this weekend.



Terri
 
I would guess diodes like you said. Most often when output voltage is a problem, the diodes are the culprit (as from my own experiences anyway).
 
Redhook98 said:
I would guess diodes like you said. Most often when output voltage is a problem, the diodes are the culprit (as from my own experiences anyway).
Click to expand...

Thanks Redhook. I am hoping that my 'generic' diodes will work. I found some that have the same specification (26A, 1600V) from allied electric and have them in hand. The only question is thread pitch. At $6.32 each they are an ok bet given the set from a westerbeke distributor cost > $120.00. If this doesn't work it's going to have to wait until spring as it's coming out of the water and getting winterized this weekend.
 
Ugh! Access to the diodes on the rotor is a pain in the butt. Yes, they're regular silicon rectifiers, with a high current and PIV rating. Didn't realize that they were rated at 26 amps!
 
fc3 said:
Ugh! Access to the diodes on the rotor is a pain in the butt. Yes, they're regular silicon rectifiers, with a high current and PIV rating. Didn't realize that they were rated at 26 amps!
Click to expand...

Yea, the manual says they're rated much higher than the circuit needs. The manual also says those aluminum shields can be bent back to get better access to unscrew them. I am hoping that's the case because there isn't a lot of room through the removable cover.

Terri
 
Hi all, I ended up changing Diodes as well this weekend (but after winterizing).
And the diodes I purchased from Allied Electric were the right ones, in fact same exact part as the ones I removed. Here is the link.
http://www.alliedelec.com/search/productdetail.aspx?SKU=5500064
They are $6.32 each from Allied versus $125.00 a pair from westerbeke dealer. Also, if you still have the original Denso plugs and don't want to pay a kings ransome for replacements. I have found that NGK BPR5ES-11 plugs are replacements as well (all of 6.03 from Amazon). I can only imagine what westerbeke dealers want for them.


Terri
 
Theresamarie11 said:
Hi all, I ended up changing Diodes as well this weekend (but after winterizing).
And the diodes I purchased from Allied Electric were the right ones, in fact same exact part as the ones I removed. Here is the link.
http://www.alliedelec.com/search/productdetail.aspx?SKU=5500064
They are $6.32 each from Allied versus $125.00 a pair from westerbeke dealer. Also, if you still have the original Denso plugs and don't want to pay a kings ransome for replacements. I have found that NGK BPR5ES-11 plugs are replacements as well (all of 6.03 from Amazon). I can only imagine what westerbeke dealers want for them.


Terri
Click to expand...

A thread was started about a month ago for generic replacement parts... This would be a good one to add... I think I paid $14 a piece for the WB plugs...
 
Guys, I thought I should wrap this one up now that I was able to start the generator this spring with the new diodes installed. The generator immediately came up to 120Volts and took any load I could throw at it. Hurray!!! And the generic diodes, at $6.32 from Allied Electric, worked fine. I also took the time to change the belts, change the oil in the governor, and replace the impeller, plugs and anode in the heat exchanger. All set for the year I think!
 
Someone here is going to complain that you didn't use "marine" diodes ;-)

Glad it worked out for you!
 
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