Generator Voltage

J

joegag

New Member
Mar 2, 2009
65
Yorktown, VA
All of a sudden, it seems like my quicksilver 5.0 generator is putting out too many volts. I realized it when I turned on my AC unit, and the meter on the distribution panel pegged, so I shut it off immediately. Now the microwave doesn't work on either shorepower or generator. Checking the voltage at the AC outlets in the boat, on shore power they read 119.5 and when I energize the gen set, it reads 175..any ideas? Hope it's simply an adjustment, I just now got the gen set running good!
 
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The microwave is toast. You might luck out by just replacing the MOVs. There about 3/4" flat discs that usually show signs of physical damage when they fail. They are near the AC input.

The gen PRM determines the frequency, not voltage.

The automatic voltage regulation, that controls the stator current has failed on the gen. It sounds like it has maxed out.

It doesn't sound like the diode pack, but it wouldn't hurt to test those too.

Does your gen manual describe the AVR tests?

Please don't attempt diagnosis or repair ifin this is beyond your skills. Many of the tests are performed on an operating engine. Most of the voltages and currents may be lethal. This is not a trivial task.
 
Checked the manual, and I don't see anything regarding the AVR tests...do you think parts are available? Will a marine mechanic know how to handle the repair, or do I need a generator tech? This don't sound good for me now does it?
Guess it could have been worse if it happened while the AC was on. Better not run it anymore...correct?

BTW - all of my 12 volt lights in the main cabin aren't working either..is it possible all related?

Appreicate your help!
 
Is your battery charger putting out the correct voltage to the batteries? Check the fuses inside your charger before you write off this piece of equipment. What is the voltage at the batteries? What is the voltage at the DC panel? Is your battery switch(s) in the "On" position? Did your battery charger get fried as well? Try taking a separate 120 volt power cord from the dock (bypass the boat) to test out all of your 120 volt loads such as your M/W, fridge, battery charger, etc. for proper operation to confirm whether these items are actually shot or whether some other issues are in play here other than the Genny.

~ Ken
 
Joe,

Lots of good info here. If you aren't comfortable around electrical things get a generator technican since this appears to be an electrical more than mechnical problem. As mentioned the generator overvoltage is probably due to a voltage control failure. Anything directly connected (switched on at the AC breaker panel) to the generator AC should be checked, water heater, AC/heater, TV, battery charger and so on...don't forget the GFI outlets they are probably fried too. Also check your fuses, breakers, then start with AC from dock and trace thru your boat system.

Good luck
 
Well, I finally did check everything...all AC outlets, water heater, refer, TV are fine...so the microwave is shot (bt the power going to is still 120volts) and my battery charger is fried, so I have to replace that....Guess, all in all, I'm lucky.

Now I have to see if I can figure out what the problem with the gen set is...story of my life, finally get the damn thing running good ... and not it's putting out too many volts. Looking at it, if it needs any major reairs, I'd bet I'll have to pull my stbd engine to get to it!

So, unless it's something simple, I may be without a gen set for the summer... CRAZY!!
 
Joe,

Check the microwave and charger for an internal fuse, sometimes they have a fuse in series with the incoming AC. With the overvoltage you experienced this fuse may have opened. If this is the case replacing the fuse may bring it back to life.
 
The marine gensets that I've seen use brushless stator designs. Therefore, voltage regulation is engineered into the system by matching the exciter windings with a capacitor. Almost positive that your high voltage problem is the capacitor. It's probably off spec. Do not replace with a generic electrolytic capacitor that's "close enough" in MFD ratings. It's must be exact the right spec. Don't also try to use a cap from a 7 KW genset if you have a 5 KW model, etc.

Generally, there is no voltage regulator for the A.C. output, but there might be one for the battery charger.

Best regards,
Frank C
 
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Are these parts available easily? I've someone coming over this w/end to check the frequency out and see what's up...I was hoping it was only the voltage regular, the m/wave & charger is shot. Funny, the ac breaker on the panel didn't go first...I still have 120 volts at the wire when I dis connected the w/wave.
 
Quick update...ran some tests and determined (I hope) the voltage regular is fried on the gen set...evertime we tried to adjust the voltage, it immedately went back to about 192 volts...ordered a new one on thursday (not cheap), and should have it Tuesday, hopefully this will do it and I'll be ready for our memorial day cruise...with a gen set...time will tell!
 
Quick update, I replaced the voltage regulator today, had to adjust the voltage and check the htz, all is well! I was lucky enough to have the manual, so it walks you thru things step by step...so, for $225 Im set for this w/end cruise...
 
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