Generator Voltage Failure

[normanton]

Tested one of our generators this morning, only about 76KW engine set. Started up fine, took the load of the building fine, connected a load bank, fine. Voltage readings all 240ish, temperature as expected, oil temperature as expected, coolant temperature as expected. 1.5hours later. Chug chug chug. Generator fails. Switches back to mains supply.
Fault on genny is “alternator volts fail”.
My first instinct is failed AVR. Runs genny again off load, readings are 240,241,242v (3phase obviously). So now what? Lol.
Possibly a faulty alternator? Is it worth checking the stator winding? I’m electrically biased and my mechanical knowledge is basic I’ll prewarn you. Thanks in advance.

 

[westward10]

What percentage loading did the bank and building put on the generator.

 

[Pete999]

Does the standby set have any bushes that may be worn down to far and not making contact on the alternator slip rings?

 

[elsparko]

mate, its saturday get yourself down the beer garden and worry about this on monday

 

[MDJ]

mate, its saturday get yourself down the beer garden and worry about this on monday

LOL, it's POETS day, you have started early

 

[elsparko]

LOL, it's POETS day, you have started early

so it is LOL

 

[westward10]

Here we go again.......

 

[MDJ]

Like I have said hundreds of times here, the Jocks are constantly pi$$ed lol, say no more pmsl

 

[normanton]

What percentage loading did the bank and building put on the generator.

Our compliance requires us to run them at 110%. But I think we were just short of that so it was approx 100%.

 

[Pete999]

Does the standby set have any bushes that may be worn down to far and not making contact on the alternator slip rings?

Sorry Bushes should read BRUSHES

 

[davesparks]

‘Chug chug chug’ to me suggests that maybe the engine has an issue maybe fuel filter or the water separator hasn’t been emptied in a while.

 

[Pete999]

‘Chug chug chug’ to me suggests that maybe the engine has an issue maybe fuel filter or the water separator hasn’t been emptied in a while.

Ah yes Dave, couldn't really be electrical, if the Prime mover is playing up, fuel problems, injectors blocked, filter blocked, over heating, needs a diesel Mechanic to have a butcher I would think.

 

[loplug]

Sounds like a engine side failure. Because of the alternater fault I would check all the electrical connections related to it. If it is a stand by set I’m guessing the trickle charge set up will replenish the battery’s and perhaps hide the altonator fault if it’s only ran for short periods

 

[normanton]

Sounds like a engine side failure. Because of the alternater fault I would check all the electrical connections related to it. If it is a stand by set I’m guessing the trickle charge set up will replenish the battery’s and perhaps hide the altonator fault if it’s only ran for short periods

Yes mate it’s a standby set. 24v starter battery which is charged via a 24v rectifier (from the engine control cab).
I see what you’re saying though.

 

[normanton]

Ah yes Dave, couldn't really be electrical, if the Prime mover is playing up, fuel problems, injectors blocked, filter blocked, over heating, needs a diesel Mechanic to have a butcher I would think.

I think that’s a good idea checking the fuel filters etc. It’s in a remote area and probably runs for around 4-5 hours a year, if that

 

[Pete999]

I think that’s a good idea checking the fuel filters etc. It’s in a remote area and probably runs for around 4-5 hours a year, if that

Fuel may have gone stale.

 

[elsparko]

I think that’s a good idea checking the fuel filters etc. It’s in a remote area and probably runs for around 4-5 hours a year, if that

how long has the fuel been sitting in there?

 

[elsparko]

I think that’s a good idea checking the fuel filters etc. It’s in a remote area and probably runs for around 4-5 hours a year, if that

how long has the fuel been sitting in there?

 

[MFS Electrical]

Like I have said hundreds of times here, the Jocks are constantly pi$$ed lol, say no more pmsl

How else do you expect us to cope with the normally dreich weather?

 

[davesparks]

. It’s in a remote area and probably runs for around 4-5 hours a year, if that

The poor engine probably hasn’t even been properly run in yet then!

 

[Andy-1960]

Customer of mine decided to go green and buy bio-diesel for their standby generators. Trouble is the stuff doesn’t keep and turns to some sort of sludge. They came to test run some of the sets and they all cut out after a few minutes. They then had to spend a fortune replacing filters and cleaning out injectors then having the tanks pumped out and cleaned prior to refilling with proper diesel!

 

[loplug]

Customer of mine decided to go green and buy bio-diesel for their standby generators. Trouble is the stuff doesn’t keep and turns to some sort of sludge. They came to test run some of the sets and they all cut out after a few minutes. They then had to spend a fortune replacing filters and cleaning out injectors then having the tanks pumped out and cleaned prior to refilling with proper diesel!

proper diesel aint what it used to be now its ultra low sulphur and can suffer the same enzyme sludge as the biofuels

 

[grantr37]

There's a regulator on a heatsink which has worn out, new one is about £30 this powers the Pcb which has the exciter driver that does the output regulating when the load goes up, you'll see the module screwed onto the engine body where the heat from the engine knackers it.. You can get one online, they are rivited shut and disposable

 

[Pete999]

Do the S/BY set have any kind of fault diagnoses charts you could look at? these thing are so well built and tested it could be something very simple, please leet us know the outcome.

 

[grantr37]

Customer of mine decided to go green and buy bio-diesel for their standby generators. Trouble is the stuff doesn’t keep and turns to some sort of sludge. They came to test run some of the sets and they all cut out after a few minutes. They then had to spend a fortune replacing filters and cleaning out injectors then having the tanks pumped out and cleaned prior to refilling with proper diesel!

There used to be a few people near me that made bio diesel for themselves and had bought all the machinery and chemicals to add into it, they got a visit from the customs and tax and that was the end of that, no more collecting chippy veg oil.
Now refineries are adding veg and ethanol in and your car diesel and petrol are duff, the fuel you buy can void your warranty as the chemistry doesn't match the manufacturers benchmark for fuel.