Investigation on the Rotor Voltage and the Rotor Frequency in Wound Rotor Induction Motor by the Slip Change

Abstract

The slip in asynchronous motors is the synchronous cycle ratio of the rotor speed difference with the synchronous speed. It is known that in three-phase asynchronous motors, rotor voltage and frequency change with slip. In this study, the induction motor with rotor winding is connected to stator star and grid voltage is applied. The rotor windings are star connected in themselves. The voltmeter and the frequency-meter are connected to the ends extracted by means of the bracelets to measure the rotor voltage and frequency. With the help of the universal motor, the induction motor is rotated in the direction of the rotating field and in the opposite direction of the rotating field and the interpretation of the change in rotor voltage and frequency depending on the slip has been made. When the rotor rotates in the direction of the stator rotating field, the rotor voltage and frequency decrease as the rotor revolution increases, and when the rotor speed reaches the stator rotating field speed, the slip, rotor voltage and frequency become zero. When the rotor rotates in the opposite direction of the stator rotating field and the rotor speed is increased, the slip value exceeds 1. The rotor speed is increased until the rotor voltage reaches 200 Hz and the increasing in rotor voltage and frequency have been observed.