Motor slip calculator

An induction motor turns a little slower than the rotating field, and that gap is the slip. The rotor currents it produces have a frequency of their own: slip fraction times supply frequency, so a 4% slip on 50 Hz means 2 Hz in the rotor bars. Typical full-load slip runs under 1% on large machines to 5% or more on small ones, per IEC 60034-1 rating practice. Speeds above the field are kept and reported as negative slip: the machine is then driven, not driving.