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15KW Westerbeke Gen issue

Discussion in 'Generators' started by CSkipR, Sep 22, 2012.

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  1. CSkipR

    CSkipR Member

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    Went fishing yesterday. After approx 8 hrs of gen running all of a sudden 110/240 power shutdown and gen shutoff. Today checked oil, water, etc and restarted gen and it ran fine except the voltage meter by the gen panel every few seconds it would jump back and forth between 25 & 27.5 volts.
    Any ideas where to start?
  2. Capt Ralph

    Capt Ralph Senior Member

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    Not Onan?
    Skip, other than recycling the breakers, there is not much else easy & safe things to do.
    There are procedures for testing voltage levels at various points while the engine is running. Not safe for the un-trained.
    To make things worse, if it's an electrical item (board, relay, diode) there is no warranty on that part unless a qualified service tech installs it.

    Tap on Keven or your favorite Westerbeke shop and not get fried.

    ,Ralph
    ,, with past curled hair
  3. CSkipR

    CSkipR Member

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    Hey Ralph I am a pretty good electrician just haven't done much with a generator? Mostly house wiring.
  4. Beau

    Beau Senior Member

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    SkipR

    Not sure I understand your data. Did the gauge that now reads 25-27v previously read 230-240v? If so you should have a tech look at the generator side of things. What does the salon meter read? Is you AC current working when you are on the genny? Maybe its just the local meter. Anyway, House wiring ain't like working on a high volt/ amp generator. Just saying.... Always enjoy your posts, hate to see them suddenly stop.
  5. CSkipR

    CSkipR Member

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    Beau,
    My error, the gauge normally reads approx 26 volts. This is the salon gauge. I believe this just shows the normal starting and operating voltage. The vessel is a 24v dc system although normally reflects approx 26vdc when charging. What is odd is the needle on this gauge started fluctuating as mentioned previously and I am wondering if this has something to do with the loss of AC power 120/240.
    When I started the gen today I was able to turn ac power on but noticed in the salon the gauge fluctuating which it normally doesn't do so I shut it back down. Possibly a battery or rectifier maybe.
  6. Beau

    Beau Senior Member

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    What about on shore power? Maybe you have a loose lead? So the genny is fine? Does your ac meter read 220+?
  7. Pascal

    Pascal Senior Member

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    Going back to the first post, i read it as the genset shut down and AC power loss happened at the same time.

    Then upon restart you noticed DC voltage fluctuating.

    If that s the case, i would look at loose wiring on the DC side, start at the DC Alternator and trace the wiring to the battery. I don't think the AC side is an issue, on a WSTBK I m pretty sure AC voltage has any impact on the engine DC voltage although it s been a while since I ve had to mess with a WSTBK

    If you have a problem on the DC side (loose wire) and loose power, it could shut it down
  8. CSkipR

    CSkipR Member

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    Pascal you have the scenario correct. While running the gen shutdown shutting off all ac power. Restarted gen and noticed that dc meter inside salon was fluctuating between 24 -27vdc. All 120/240v power appears to be okay. AC power is fine on shorepower. This morning I noticed that the 240v battery charger breaker was off. Possibly I did this before fishing trip, not sure. I'm not totally up to speed on the boats wiring but wonder if that could cause the generator shutdown if generator batteries (2) get to low of voltage? When the gen is running wouldn't it charge its own batteries?
    Will check the dc side for any loose wires.
    Thanks
  9. Beau

    Beau Senior Member

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    SkipR

    Let us know what you find. Thanks
  10. Capt J

    Capt J Senior Member

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    I had a Westerbeke do this on a trip. Sometimes it would run for 8 hours, shut down, and maybe re-start maybe not. Sometimes it would shut down after 20 minutes.....it turned out to be a bad diode......a good electrician with the wiring diagrahm should be able to diagnose it in an hour......maybe 2.
  11. CSkipR

    CSkipR Member

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    15kw Generator Issue

    May have found the issue. I had accidently turned off the 240v ac onboard battery charger before leaving the dock and the batteries may have discharged enough in 7 hrs to cause a low voltage shutdown through the generator dc breaker. Just a guess will have to run it for awhile to determine.
    __________________
  12. Pascal

    Pascal Senior Member

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    Again I don't recall how the WSTBK is setup but I think it has a belt driven alternator to keep it s battery charged. The onboard charger should not be needed.
  13. Capt Ralph

    Capt Ralph Senior Member

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    Skip
    Thought it was a ACv problem. I miss read.
    An Alternator and a battery charger on at the same time may cause the DCv meter to bounce around while the automatic parts of both the charging regulators fight each other. A breaker may trip if the charger looses. Damage may accrue to the alternator if it looses.
    The run solenoid and relays need DCv juice to run. A simple loose wire or bad crimp can bring her down.
    Leave the ships battery charger off for a few hours. Put a DV volt meter on the gen-set cranking battery, measure B+, crank her up and let run for a minute. Re-measure B+. If the alternator is good, you should have more juice running than before.
    Measure V+ at the run solenoid. That will be just under B+. < .1 DCv difference. If it's much lower, look for a bad crimp or relay.

    On some of the newer genies, a DCv OK signal is required before the ACv regulator is allowed to kick in and make the big juice.

    Tell us what you find,
    Ralph
  14. CSkipR

    CSkipR Member

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    15kw Gen Issue

    It was caused from the battery charger being accidently turned off before the trip. According to Cabo the battery charger should remain on even when running engines and generator according to Cabo. Thanks
  15. Pascal

    Pascal Senior Member

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    I call BS on that explanation!

    So if the battery charger fails, you have no way of keeping the generator running?? That s just plain stupid...

    I have a feeling that whoever gave you that information doesn't know what he s talking about... The generator should have it s own alternator to keep its battery charged
  16. CSkipR

    CSkipR Member

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    The way they explained it to me was the 4 house batteries were being depleted and the low house voltage more than likely caused the dc gen brk to trip and shutdown. Will see what happens the next time I run it for 8-10 hrs. We ran it for over an hour and it never had an issue.
  17. Pascal

    Pascal Senior Member

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    But the alternators on the mains should charge the house bank under way!

    And the generator should have its own battery, so the house bank doesn't affect the genset...
  18. sunchaserv

    sunchaserv Member

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    House power on most vessels, both 110 and 12 or 24 is drawn through the house batteries. As suggested, loose house battery wiring or a bad battery may result in voltage fluctuations.

    Assuming you have an inverter charger combination, your house batteries will be charged via the genset and or the engine alternators when cruising. A Westerbeke genset shutting down can be due to high temperature, low oil pressure or an internal generator side only electrical fault. Not to be ignored would be a faulty emergency shut down circuit or bad stop solenoid. There is lots to check out and consider.

    Do you have an inverter system monitor to assess house bank health? A VOM check around things may show you the problem area too.
  19. Capt Ralph

    Capt Ralph Senior Member

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    I have to call passable Bunk on that also. But, while typing under the influence, try to follow me,, Chargers off while alternators are on line. On my Detroit's with Raratain chargers, there is a lead that turns the chargers off when the mains are running should I forget to turn the chargers off manually. Maybe that could be the thought for your reps comment, auto off. The regulators (charger & alts) will never stabilize and damage can occur if all are active at the same time. If the charger is off and batteries die, then something has passably already been damaged.
    Preform my little south Georgia test on all batteries and alternators one at a time with some time between test, to see if anything is getting charged while running. Gen-set should always have it's own battery. House batteries are usually charged by the mains.

    The only way I can see house batteries getting low is at anchor, running gen-set without the charger. As I'm typing I can see a confusing window here... House batteries are usually charged by the mains or charger. Then on gen-set you would need the charger to keep the house batteries up. If it's a multi point charger and a lead is to the gen-set battery, there could still be a fight between the charger and gen-set alternator, but I can see an answer,, that the just of the current would be going to the house batteries and not really feed much current to the gen-set battery unless it was low,, meaning,, Bad gen-set altonater....
  20. Capt J

    Capt J Senior Member

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    Ok Skips particular Cabo, the boat does not have overly large battery banks, the electrical demand can/is a lot, and the alternators WILL NOT keep up with the electrical load on the house bank as it is only charged through a battery isolater. The boat is designed to be run with the generator running and battery charger on, for his particular boat.