How much current will a 3phase,208v,7.5hp motor use

According to the National Electric Code, a 7.5 HP 3 P 208 volt motor is rated at 24.2 amps and the feeder and other components of the circuit need to be rated 125% of this rating.

The actual nameplate rating of your motor may be different, use the NEC rating to size your feeder.

The powerfactor given in the name plate too should be considered