Phase converter for fire pumps

[SprinklerDesigner2]

I have a job in the sticks that requires a 125 HP vertical turbine fire pump.

Three phase power is not available so I bid using a diesel engine driven fire pump. I think 460 is available but could be 208 volt too. Didn't do a lot of research having dropped it as soon as I learned 3 phase not avalable.

The owner asked if it were possible using a phase converter and while I don't like the idea I did tell him I would look into it.

Are they even allowed? If they are allowed how much would one of these cost?

The electric would be by others.

 

[pipesnpumps]

hm, that is a tough one..

I know you probably already know this, but there is quite a bit of language in NFPA 20 and the NEC about the rules on the components in the power supply circuit.

The phase converter would have a disconnect, etc. and is another potential failure point that would basically defeat all the language in NFPA 20 meant to maintain the integrity of the supply circuit.
If I were you, I'd quote one those sections and use it to prove why it can't be done..

You could probably also brush this idea off with a quick calc of the amps needed for the supply voltage. It sounds like you might have 220V single phase, and to run 125 HP on that you'd have to have a wire as big around as a baby's leg..

 

[SprinklerDesigner2]

Firepumps,

I feel very uncomfortable when a customer asks about something electrical. I know just enough about it to be highly dangerous.

When the owner first brought it up I told him I didn't like the idea whereupon he pressed me why not? The only answer I could give was just one more thing to fail.

In the proposal I made it clear electrical was by others and I suggested he retain the services of a an electrical engineer or qualified electrical contractor.

But we'll end up with a diesel. Went shopping for phase converters, the big ones get costly and on top of this the pump will be 1,200 feet from the nearest power pole. He's going to pay enough for a 200 amp 120v service.

 

[fsck]

Is 3-phase not offered there, or not currently used? I.e. can the utility supply it, but the customer has not needed it before, so the incoming is single-phase.

If 3-phase is not available, I'd be surprised if there was enough electric power of any form to run 125 HP of motor. So that's the first question to resolve -- what can the utility offer?

I suppose a 125 HP phase converter may well be out there; after all they run subway cars with 160KW motors off of them. But the price may deter you.