Going from 800 HP to 1200 HP motor - driving pump

[eestults67]

I have a project that will require me to use a (4160)1200 HP motor in place of the old (4160)800 HP motor. If by looking at the pump required torque curve and the new motor torque/current curve. Is this a viable way to determine the size CT's I need to purchase, or is there a better way.

Thanks,

Tim

 

[racookpe1978]

Nameplate speed of the motor is the same, right?
Startup time length and intervals betweens startup are still the same also, right? (You are not going to be changing how the motor + pump operate, that is.)

 

[dpc]

I would size the CTs based on the motor nameplate FLA regardless of the driven equipment. ~125% of the motor FLA generally works out. However, the existing CTs may be fine if they have adequate thermal rating and the driven equipment is not changing. You don't need speed/torque curves to size CTs. You might also see if existing CTs are multi-ratio.

 

[eestults67]

racookpe1978,

Yes, motor speed is same. startup time might be faster due to bigger motor,more starting torque. The motor will run 24/7 once we have it pumping, so no changes on pump operation.

dpc,

Motor FLA is 156, current CT's are 150:5, no multi-ratio.


All,

Got my hands on pump curve and run data,pump usally runs at full load, which means we will use about 66% of the rated capacitiy of the 1200 HP. Outside of start-up and the changes I've got to make to my protection, I'm guessing I will be OK with current CT's?