How many amps will a 55 KW motor take?

Answer 1

250 kW= 250,000 watts

1 horsepower=746 watts (The motor is approx. 335 horsepower. (just FYI))

The Ohm's Law formula for this is:

P(Power in watts)=I(Current in amps) x E(Voltage)

Since the voltage is unknown, I will give you different options based on input voltage.

I will assume three phase power for a motor this size.

So, back to the formula:

250,000=I x E

Let's assume voltage (E) to be 480v:

250,000=I x 480

I=520 amps

For a voltage of 208 (much less likely for this size motor):

250,000=I x 208

I=1201 amps

These are 'running' currents only. The amount of starting current will be much, much higher, but only for a brief period.

Answer

The above answer assumes that the motor's input power is 250 kW. But this is not the case.

The power of a motor is always expressed in terms of its output power, not its input power! In North America, this is expressed in horse power, whereas everywhere else it's expressed in watts. So, to determine the current drawn by the motor, you have to start by determining its input power (input power is output power times efficiency); if you don't have a means of determining the motor's efficiency, then you cannot really find out its input power, in which case, you cannot find its current.

Answer 2

To answer your question, I need more info. What voltage are you using? IE. (12 volt, 24 volt, 120 volt, 240 volt) it makes a difference.

Use this formula ......... Watts = Amps x Volts

Amps = Watts / Volts

Volts = Watts / Amps

So figure out your voltage requirements, then use this formula to figure out

Amps Remember to give yourself a 20% margin.

Example 55 KW @ 120 Volts (55,000W / 120V = 458A)

458 - 20% = 366.4 Amps Available

Only use 80% of available Amps or Voltage otherwise your wiring

will heat-up over time and fail.

<<>>

To answer this question the voltage of the motor has to be known.

Comment

You also need to know its efficiency, because a motor is rated according to its output power*, not its input power. So, in this example, its input power will be less than 55 kW.

(*In North America a motor's output power is normally expressed in horsepower. Practically everywhere else, it's expressed in watts.)