Motor Horsepowers Not Listed

[natfuelbill]

NEC 430.250 stops at 500 HP for flc values. Without knowing a specific motor, is it correct to extrapolate the table, or to apply the "amperes when "HP" is known formula? My interest is in large induction motors around 1000 to 2000 HP.

My goal is to recommend maximum the motor horspower and starting method options based on a utility company motor starting current limit of 2400A at 480V.

 

[jtester]

Motors of that size are often run at medium voltages, 4160V for example. Why are you interested in 480 volts with that large a motor?

Jim T

 

[natfuelbill]

The utilty starting current limitation was given at that voltage current. Yes, I envision going with 4160V motor and controls.

 

[jim dungar]

Over 200HP the multipliers for approximate full load amps are:
200V = 2.75A/HP
230V = 2.4A/HP
460V = 1.2A/HP
575V = .96A/HP
2300V = .24A/HP
4000V = .14A/HP

 

[natfuelbill]

Jim -
Thank You for this information!
Bill

 

[infinity]

Over 200HP the multipliers for approximate full load amps are:
200V = 2.75A/HP
230V = 2.4A/HP
460V = 1.2A/HP
575V = .96A/HP
2300V = .24A/HP
4000V = .14A/HP

Jim your list is of approximate multipliers. Would it be code compliant to use these when calculating loads?