4.5 Westerbeke gas BCGB Low voltage

[BoatTooSmall]

Hi,

I have one of these and it is giving me trouble. Last year I noticed that the gen was running at 60Hz, however the voltage under No-Load was only at 95 volts. When I placed load on the generator it perked up to 115 volts 60 Hz.

Now this year, the generator starts up but I have to continually hold the "preheat" button down to keep it running while the shutdown alarm is sounding. When it is running, it shows about 25 volts, but the engine seems to be running ok. I have not checked the freq while at 25 volts yet. Lots ot water discharge so flow is ok.

1) Any ideas? I'm thinking the capacitor...

2) I can get a capacitor today for short money and try it today, but need to know where it is on the genset. (how to access it)

-Thanks!
Rick

 

[Presentation]

Here is the Westerbeke manual for the 4.5 Westerbeke gas BCGB
http://www.westerbeke.com/Online_Manuals/44200_4.5bcgb_7.0bcgb_oper_man.pdf




See page 41 of the manual. (note in adobie this will be on page 53 of 68) Look at the botton of the page for the real page number.

See page 38 for 'no-load' voltage adjustment.

Note: there is a picture of the capicitator location on page 40. Its behind a louvered metal plate on the back side.


You could also call your dealer and see what they suggest.

 

[fc3]

If the output frequency is OK then the generator is turning the correct RPMs. Thus it's not any of the above. You probably are correct about the capacitor. Because the alternator is brushless the capacitor is a critical part of the tuned L-C circuit that excites the alternator. If it's off-spec, the proper field voltage will not be induced.

The other components involved (from off the top of my head) are wiring (big problem, but not likely) and the rectifiers on the armature. The rectifiers are hard to access since you have to pull the cover off the alternator. Try the cap. It's inside the metal box with the electrical connectors. You can't miss it once you pull the cover.

Best regards,
Frank C

 

[Presentation]

Hey Frank,

Even though you are choosing to hide your dot, I gave you my “I approve” for your post. If ever you decide to show off your dot it will be, well, greener! Good job!

 

[fc3]

There's a web site that was in the company news letter www.earthlab.com/carbonprofile. It calculates your carbon score. I scored a 635 (35 tons of carbon) without counting the fuel the boat and PWC burn. Being greener is something that just isn't me.

Best regards,
Frank C

 

[BoatTooSmall]

Thansk everyone. Seems like an easy fix. I'll let you know...

 

[BoatTooSmall]

Well here is the answer. First of all thanks to all who assisted.
The low voltage issue at no-load was definitely the Capacitor. (super easy to replace)
The engine dying was due to Low oil.

The genset is working wonderfully now...