When Generators Go Bad

[robiefield]

I have relied on generators for four years to boondock at my mountain land. This holiday weekend I had two generators go south on me. I've used my generators every weekend for several years so none of this is related to lack of use.

The first generator is a seven or eight year old 3500 watt B&S unit. Engine is fine. I think it's gone overvoltage though. I left it feeding the barn apartment (240V feeding the two 120V sides of the fuse panel) to run the AC, came back to find the AC off and all the incandescent bulbs blown out as well as the ceiling fluorescent light fixtures (changing bulbs did not fix the fluorescents, so I guess perhaps the ballasts on the fixtures blew?) I replaced the old style light bulbs and they blew again. Interestingly none of the 15A fuses on the light circuits nor the 15A fuse on the AC unit was tripped.

The four year old B&S 6200W gen that we use all day most summer days to keep AC in the RV (240V out to RV shore line power in) got hot on one of the four-prong plugs at the generator--the aft AC unit on the RV sometimes would load down when it needed to start, but usually would trip a fuse on the generator or RV 120V panel if it didn't get things going. The generator's 120/240 plugout now smells electrical melty and bad. I haven't found out yet if the failing 240V line on that generator also took the RV power converter with it. (I'm hoping it was just the generator leaking smoke and not the RV too.)

Can anyone point me to a good generator trouble shooting site? Or have testing suggestions? I am away from the RV but have both generators with me. I'm able to follow instructions with a voltmeter but no genius. Heck, I can't even find a place that works on generators near Raleigh NC using my google-fu. Where does one go? Small engine shop? RV store? Ideas?

I don't really know what to look for electrically on portable generators. Any suggestion will be useful to me.

 

[Argosy]

Generators need a fair amount of specialized equipment to repair, a tachometer, load bank and frequency meter are vital. You will need a manual for trouble shooting. And probably the most difficult (especially for the older generator), you will need a source for parts.

Check the voltage out of each but your guess that at least the smaller one is over voltage is probably right on. FWIW, a circuit breaker trips on current draw, over voltage won't affect it.

Check the connections on the RV wiring. Because of their mobile use they tend to loosen then corrode over time. That will cause resistance and over heating and smoke

If the one in the RV is an Onan parts and manuals are available, but expensive.

http://www.cumminsonanstore.com/

Flight Systems has some controls for Onan generators, cheaper and better quality.

Generator & RV Controls | Engine Monitors | Idle Limiter | Repair & Rebuilding Services

If they are homeowner grade units I would start looking for deals on new ones. If this is something you expect to be long term maybe even think about a single better quality unit. If they're left running unattended failure can be expensive, to the point of burning down buildings. What you save short term can be very expensive long term.

 

[robiefield]

Useful info: the 6200 watt generator is a Briggs and Stratton Generac model 030201. I removed the control panel and the 30A 120/240 locking outlet is burned up. I'm going to guess the connection got loose or dirty, resistance built up, and the connector got very hot and melted / burned the hot wire connection away.

the 3500 watt generator is a 6.5 hp B&S motor with a Generac 01313 electrics. It is the one that blew out the lights. I am reading 156-158V out at the 120v outlets. How can I turn that down?

 

[Phils]

Useful info: the 6200 watt generator is a Briggs and Stratton Generac model 030201. I removed the control panel and the 30A 120/240 locking outlet is burned up. I'm going to guess the connection got loose or dirty, resistance built up, and the connector got very hot and melted / burned the hot wire connection away.

the 3500 watt generator is a 6.5 hp B&S motor with a Generac 01313 electrics. It is the one that blew out the lights. I am reading 156-158V out at the 120v outlets. How can I turn that down?

This prob'ly won't help your situation but if I DIDN'T post my experience and it IS your problem, it's an easy fix.

I live off grid and have been using generators for decades.

One went into an overvoltage situation, blew some lights and electronics. It's a Honda, and indications were that the voltage regulator was the problem (over $300 from Honda). Replaced it. Fine for a few years.

Same thing happened again. Replaced the regulator and all was fine again.

A few years later, same thing again. But what I learned was that by disconnecting and reconnecting the two electrical connectors for the voltage regulator, the problem went away.

It's only a backup generator, but before using it I simply disconnect and reconnect those plugs and it works fine. And I still have a good voltage regulator sitting on the shelf (dang, but I tossed the first one).

Phil

 

[300UGUY]

I found that on the cheaper units, I was better off buying new.

 

[techman]

Check to see if the neutral wire gas a good connection. If you lose it, you may have 240 V leg-to-leg, but you might have 170 and 70 or any other combination of 240 volts. If the generator is a higher end it will have a voltage regulator. It will be a circuit board. If not, it will be a saturated core, inherently regulated. These have the proper voltage at a defined speed. So if the engine is running fast, the voltage will be high.

I would run the genset w/o the load and use a voltmeter an see what you have for voltages.

paul

 

[Larry Caldwell]

Cheap generators have aluminum windings instead of copper. If they draw moisture, they short out and die. The connectors heat and corrode. Store them in a dry environment, don't use them outside when it is raining, and if you can get to the connections, buff them with antioxidant paste and re-torque the connectors.