How many amps will a 55 KW motor take?

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.

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.