250kVA DG R Phase Not Coming at Load

1. Let your operator's manual guide you.

2. If you don''t have one get it.

3.If that doesn't work, CALL THE MANUFACTURER.

4. Be prepared to spend money to fix this generator.

You don't have anybody there who can fix this or you wouldn't come here.

MCB in the control panel for indicating lamps and voltmeter. it looks to me some wiring issues in the control circuit. I have to to presume these , without any valid drawing. my humble suggestion would be get hold of qualified Elec engineer to measure the voltage output at the alternator terminals, with help of multimeter. if your voltage readings are in order, then DG set is fine , and issue is with control circuit. perhaps neutral wire in the control circuit is broken. please check and respond.

Dear Mr.Basavaraj,

Did you measure the voltage at R phase, when the Generator is started.

I suspect the R phase got opened and hence there is NO SUPPLY. If the voltage is measured in R phase, it could be due to a small wire is in contact to volt meter.

Voltage of 110 Volts in R phase confirms my doubt, - which is similar to the HG FUSE blowing out in Transformer for example 11 KV/420 Volts. System. In the Transformer if HG fuse blow out, you will face a similar situation as you are facing.

Pl. engage a competent Electrical Engineer or call the Service Engineer of the DG set supplier and check for it - mainly winding discontinuity in R phase.

Pl. inform this Forum, what ws the problem and what is the remedy sought.

DHAYANANDHAN.S

"When we Switch On the Control MCB,s in Panel Red Phase Supply Cut Off and Neutral show the Voltage of 110V."

Are you stating the Red Phase is tripping offline as soon as you close the control circuit breaker? Or are you stating the voltage indication for the Red Phase is indicating zero?

If tripping the Red Phase; Are the two system connected in parallel?

If so; Is the synchronization circuitry operating correctly?

Has the system been worked on recently?

If this is a new issue it could well be that the voltmeter is either not wired correctly due to recent repair/replacement or the "Red Phase" voltage circuit contacts inside the phase selector switch have failed.

A wire-by-wire voltage checkout of all circuits with the DG running should reveal the cause but you must check from the DG output terminals through each circuit point-to-point.