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Westerbeke 12.6BTD speed adjustment

Discussion in 'Generators' started by Capt Maritime, Jul 11, 2023.

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  1. Capt Maritime, Jul 11, 2023
    #1
    Capt Maritime

    Capt Maritime Member

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    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?

    Westerbeke 12.6BTD throttle linkage.jpg
  2. Pascal, Jul 11, 2023
    #2
    Pascal

    Pascal Senior Member

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    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
  3. Capt Ralph, Jul 11, 2023
    #3
    Capt Ralph

    Capt Ralph Senior Member

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    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.
  4. Capt Maritime, Jul 11, 2023
    #4
    Capt Maritime

    Capt Maritime Member

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    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
  5. Capt Ralph, Jul 11, 2023
    #5
    Capt Ralph

    Capt Ralph Senior Member

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    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.
    Last edited: Jul 11, 2023
  6. Capt Ralph, Jul 11, 2023
    #6
    Capt Ralph

    Capt Ralph Senior Member

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  7. Capt Maritime, Jul 11, 2023
    #7
    Capt Maritime

    Capt Maritime Member

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    Thanks for all the input guys. More research is in the works. RPM was checked with a hand held RPM meter. RPM Check Westerbeke gen.jpg
  8. Capt J, Jul 12, 2023
    #8
    Capt J

    Capt J Senior Member

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    Have a valve adjustment done on the generator and a Westerbeke tech out to do that and then check all of the settings.
  9. leeky, Jul 12, 2023
    #9
    leeky

    leeky Senior Member

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    Shouldn't 1815 RPM produce 60.5 Hz?
  10. Capt Ralph, Jul 12, 2023
    #10
    Capt Ralph

    Capt Ralph Senior Member

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    Yes, Now that I use a calculator, every 30 RPM is 1 Htz.
    It's the loss of the slow brain cells.
  11. Capt Maritime, Jul 13, 2023
    #11
    Capt Maritime

    Capt Maritime Member

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    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.
  12. leeky, Jul 13, 2023
    #12
    leeky

    leeky Senior Member

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    The no load RPM should be 1845-1860 for 61.5-62 Hz. That's 5 more RPM you have to play with.:D
  13. Capt Maritime, Jul 16, 2023
    #13
    Capt Maritime

    Capt Maritime Member

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    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.

    Woodward DPG govenor.jpg
  14. Capt Ralph, Jul 16, 2023
    #14
    Capt Ralph

    Capt Ralph Senior Member

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    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?
    Last edited: Jul 16, 2023
  15. Capt Maritime, Jul 16, 2023
    #15
    Capt Maritime

    Capt Maritime Member

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    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.
  16. Capt Ralph, Jul 16, 2023
    #16
    Capt Ralph

    Capt Ralph Senior Member

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    Laptop software on the brands website.
    But if your happy, walk aweigh.