Generator Testing

[Shujinko]

I am designing a renovation project where I have to make a recommendation on whether an existing generator is in good enough working condition to be kept or if it needs to be replaced. The generator is a CAT 600KW/750KVA, 480Y/277V, Diesel unit with sub-base tank. The gen-set unit is 30 years old but doesn't have a history of any problems and is maintained regularly. I have recommended performing the following testing:

Insulation Resistance Testing on the generator windings.
Infra-red testing on the generator lugs and terminals.
Load bank testing per NFPA 110 requirements.

What other testing or items should be looked at to make a recommendation on this existing generator? How long is the service life of a generator with these characteristics? 40 years?

 

[petersonra]

I'd be more worried about the engine than the generator itself. I'd get Cat to send a tech out to look at the diesel engine and give it a close inspection and test.

 

[GoldDigger]

I'd be more worried about the engine than the generator itself. I'd get Cat to send a tech out to look at the diesel engine and give it a close inspection and test.

:thumbsup:

For an engine in this kind of service, what a shade tree mechanic would think of as well maintained may overlook some critical items on the manufacturer's maintenance list. Including things like compression testing the cylinders and doing a metal assay on the used oil. A friend is a heavy equipment mechanic for our local Cat dealer, and it is amazing how willing many customers are to defer recommended work until the engine finally fails. And that is for mission critical engines!

 

[paulengr]

May want to test the breaker. At that age it may be seized up or the trip unit way out of calibration or not working. The load bank test mostly just tests the engine. It’s kind of a lot of money for nothing.

May want to do a PdMA test on the generator. That’s usually the best test you can get for motor/generator testing. It runs coil resistance/inductance, insulation resistance and capacitance, and PI. PI in particular in the graphical format can show cracks and crazing that passes a “megger” test.

 

[rambojoe]

I wouldn't worry about the engine itself- it will run long after you and I are gone. those cats are good for millions of miles which translates into ALOT of hours... what you can do is send a oil sample to a testing lab (or cat), whichever- but call them first and they will send you some small bottles to fill up. also test and verify the fuel too- for water and whatnot and wether it is off road (red) or on road... and of course there are a few types of diesel feul for different applications... use what the manufacture recommends. if it were my equipment, red fuel is not worth the initial savings... run clear.