A fourpole 60Hz 10hp 460V threephase induction motor operate

A four-pole, 60-Hz, 10-hp, 460-V, three-phase induction motor operates at 1750 r/min when fully loaded and at its rated frequency and rated voltage. Determine (a) synchronous speed; (b) slip speed; (c) per-unit slip.

Solution

a) synchronous speed Ns=(120*f)/p=(120*60)/4= 1800 rpm

b) slip speed N=1750 rrpm

c) slip S=(Ns-N)/Ns=(1800-1750)/1800=0.0277