Slip of Electric Motors 

The difference between the speed of the rotor and stator or stator field is called slip. Slip is one of the most important indicators of the asynchronous machines and is usually specified on the nameplate of every motor. To achieve good efficiency, the slip should be as low as possible. At a high load, however, the speed difference of the three-phase motors increases. This is because the greater the torque demanded from the rotor, the greater the drop in speed and the greater the slip. Due to this, the modern asynchronous motors are often equipped with a frequency inverter that keeps the speed of the asynchronous machine constant under any load situation.