I have a 2005 Westerbeke 12.6BTD with 3,100 hours in my Cabo 40 convertible. The generator runs great! Starts up every time with out a problem. The only issue I have is the voltage is a bit low and this past weekend it was blistering hot and we had a heavy load on the generator with the A/C's running. Then when my wife turned on the microwave the A/C tripped on low voltage. Here is the data when I test ran the generator at the dock: 113 VAC no load voltage 60 Hz no load frequency 1815 RPM no load 106 VAC loaded voltage 59.4 Hz loaded frequency 1784 RPM loaded Tech manual data: 120-122 VAC no load voltage 61.5-62 Hz no load frequency 108-110 VAC loaded voltage 58.5-59 Hz loaded frequency The throttle linkage is set at the factory and there is a cap on the adjustment bolt. I'm thinking a slight adjustment should do the trick. Has anyone had a similar issue with your generator?
RPM affects frequency not voltage. Voltage is usually regulated by the voltage regulator which should be adjustable. Don’t mess with RPM as your loaded frequency reading is excellent you need to adjust the voltage at the regulator. Even unloaded, it s a bit low. Should be 120v no load. Check the manual for regulator adjustment
Voltage IS NOT RPM sensitive, just Htz. Your Htz reading is near perfect. After you determine if the spec is PtP or RMS, and then determine if your volt meter is PtP or RMS, if your still off just a few Vac, do not touch. I realize that some owners can not keep their fingers out of things that are working perfectly well. So the next question you need to resolve, before you mess up a good running gen-set, is; What excites your windings? Pending your WorsterBroke model, there could an exciter transformer, A mylar/foil strip, or (maybe, maybe) a real AVR.
I'm not intending on messing up a good running gen-set, however I am planning to do some more research on the voltage adjustments with this generator to get things set up per the tech manual. I do not need to have equipment tripping out on low voltage. Step 1 - set the no load frequency: 61.5-62 Hz no load frequency Step 2 - set the no load voltage: 120-122 VAC no load voltage
Is your equipment tripping out on low voltage? Have you verified your meter is reading PtP and not RMS? Per your first post, no load 1815 RPM; That is 62 Htz. Probably need to verify your tach and/or Htz meter also. If you must, You will need to determine; What excites your windings? Pending your WorsterBroke model, there could an exciter transformer, A mylar/foil strip, or (maybe, maybe) a real AVR. Got to know what you have to be able to adjust it. Please research well and deep. WorsterBroke parts are not common, commonly available nor cheap.
Interesting, Just found a cut sheet that states the 12.6BTB is electronically controlled governor. Wha?? https://www.westerbeke.com/advanced specs/dslgen, 10.4-12.6btd.pdf That run solenoid may be also a fine tune governor enhancement. Not found anything on voltage regulation yet.
Thanks for all the input guys. More research is in the works. RPM was checked with a hand held RPM meter.
Have a valve adjustment done on the generator and a Westerbeke tech out to do that and then check all of the settings.
So in theory, when you do the math, to set no load frequency per the tech manual (61.5-62 Hz) my no load RPM should be 1850 - 1860.
I have the no load RPM set at 1854. The generator has a Woodward DPG governor which worked very nicely and provided good speed control. Full load RPM = 1800.
So it does have an electronically controlled governor. Well heck, that is a lot different than post #1 mechanical governor adjustment. Looked it up, cool gizmo. you can plug a lap-top into it. Did you ever determine what exciter / voltage regulator you have? Electronic? Adjustable?
Seeing Woodward governor controls on this diesel generator took me back to when I was at sea. Many of the ships I was on had Woodward governors so this was a welcomed discovery. Yes I imagine you could plug a lap top into that port, however I would probably need some software to read the data. I'm not sure on the voltage regulator question, however I'm happy with the performance of the generator now.