# Induction Motor Slip decrease with frequency decrease for same load.

by Physicist3
Tags: decrease, frequency, induction, motor, slip
 P: 45 “No-load” it does not mean “no load at all”. There are no-load losses –iron losses, ventilation and friction-bearing losses and copper losses. The no-load current-mainly reactive-is about 30% of rated and copper [winding] losses could be elevated. As jim hardy already said, ventilation and friction are proportional with square of rpm, so less frequency less rpm [rpm=60*freq/p where p= no.of pole pairs] less slip. The iron losses decrease with the frequency and so the no-load current and in turn no-load copper losses. The mechanical power requested in order to maintain the rotor in rotation will decrease even if the torque remains constant P=T*(2*PI()*Freq: $P=T\omega=2\pi_fT$ Less power less slip.