Fire pump Operation Clarification

[faresos]

I need some help on the operation sequence of the fire pump. I have 4 generators (N+1) system that is backing up the entire facility via Gen paralleling switchgear. Currently the fire pump is powered from a circuit breaker in Gen switchgear and a tap a head of the main disconnect switch. My understanding, if we lose the normal source, the fire pump controller ATS will send a signal to start up the generator(s). The ATS will transfer to the alternate source (generators) once voltage & frequency are set. My question is, does all generator(s) will be running all the time till normal power is restored no matter what if fire pump motor is running or not? In another word, if the fire pump motor is not running, does the generator(s) will be running all the time or they drop off if the fire pump is not running?

 

[texie]

A standard combination fire pump/ATS controller will send a start signal regardless of whether the pump is running or not.

 

[faresos]

A standard combination fire pump/ATS controller will send a start signal regardless of whether the pump is running or not.

Does that mean the generator(s) will be running all the time even though the fire pump is not running? The issue is the facility is powered from two normal power sources ( A &B). The fire pump (125HP) is powered from source A and the generator(s). Upon loss of source A, the system will switch to source B. The generators suppose to start upon loss of two sources to power the facility. However, if we lose source A, the fire pump controller will send a signal to the generator paralleling switchgear to start the generators. To me, the generators (3 of 2.25MW) will be running just to be in standby mode until source A is back. I think this will be a problem if the generators will be running all the time just to provide a standby power to fire pump that is not running. I hope this is not the case but that's how I see it. Thanks,

 

[hillbilly1]

If the loads of source A are picked up by source B, and the fire pump is on that same load side, the transferswitch should only see the blip of source transfer, and only call for generator power if source B is lost too. But if the transferswitch is tapped ahead and not picked up by source B, then it will call for a start and transfer even though it’s not running.