Our is a 50 KVA cummins make DG set using Power command 1302 controller. After starting the DG supply is extended to a local main breaker where neutral also earthed and then it is extended to a local distribution panel consists of number of MCB's. If we extend the supply to the local breaker it is normal. Once if supply extended to the load through any distribution panel through any MCB, irrespective capacity of load the DG is tripping. During each time it shows different fault code. coolant temp high, high AC voltage, low oil pressure etc. After disconnect the neutral it is not tripping. What could be the reason?

 

you check gen protection? what kind of protection you have??

 

The Generator is not tripping on over current or earth fault protection. As I mentioned earlier every time it is tripping with different fault code. Coolant Temperature high, lube oil pressure low etc. One time the fault code is AC over voltage. While checking the control circuit it was observed that 24V control supply is disturbed while extending the supply to the load. After disconnecting the generator neutral there was no tripping. I am not sure if we disconnect the generator neutral whether it will cause any damage to the generator.

 

Pmmeeran... What has Cummins said the problem could be?

Phil Corso

 

So far I have not refereed the issue to cummins.

 

it seems to me like you have a common fault, caused by ground. check the wiring, junction boxes, terminals. maybe a wire touching the body or cut on the wires etc.

 

Pmmeeran... How is the 12Vdc control circuit derived?

1) If derived from a battery, is the battery also charged by the engine-genset?

2) Have you not referred the problem to Cummins because the machine is out-of-warranty?

Phil Corso

 

12V DC is derived from battery and the battery also charged by the engine-genset charging alternator.

I have not refereed because it was bought during 2006.

 

Pmmeeran... the randomness of trip-cause suggests you can’t diagnose the problem because the electrical parameters like, Volts, Amps, kW, etc, are software-based and derived in the Controller. And, it powers down when the gen-set trips. Thus, after a trip you are essentially playing Pin-The-Tail-On-The-Donkey.

Here's a method I used to solve similar problems: The unit is relatively small so I suggest you install analog voltmeters (qty 3), clamp-on ammeters (qty 3), and a 1-ph clamp-on wattmeters (qty 3)! Then set up a video-camcorder trained on the instruments! The camera’s frame/sec rate should be increased some 5-10 times normal.

This method has never failed to reveal the cause of the problem.

Regards, Phil Corso (cepsicon[at]aol[dot]com}

 

Even i am also facing the same issue with the Cummings 45 KVA genset. there my genset is working fine till by all the Air Conditoners are not running. Generator is running all my company setup without any fault but as soon as i turn My Air conditioner ON, then Main MCB--inside my premises use to fall down but Generator still use to run in running mode with NO LOAD on it as MCB tripped down inside the premises.

What can be the reason for the issue..?