Electrical Engineer

  Torque in a 3 phase induction motor  is determined by three key factors: Firstly the magnitude of rotor current, secondly the flux which interact with the rotor of three phase induction motor and is responsible for producing emf in the rotor part of inuction motor, lastly the power factor of rotor of the three phase induction motor. By integrating these factors, we derive the torque equation as follows: Where, T is the torque produced by the induction motor, φ is flux responsible for producing induced emf, I 2 is rotor current, cosθ 2 is the power factor of rotor circuit. The flux φ produced by the stator is proportional to stator emf E 1 . i.e φ ∝ E 1 We know that transformation ratio K is defined as the ratio of secondary voltage (rotor voltage) to that of primary voltage (stator voltage). Rotor current I 2 is defined as the ratio of rotor induced emf under running condition , sE 2 to total impedance, Z 2 of rotor side, and total impedance Z 2 on ...

  Operating Principle of Single-phase Induction Motor A Single phase induction motor consists of a squirrel cage rotor and a stator carrying a single-phase winding. When a single-phase AC supply is fed to the stator winding, a pulsating magnetic field (not the rotating) is produced. Under these conditions, the rotor does not rotate due to inertia. Hence, a single-phase induction motor is inherently not self-starting, but requires some auxiliary starting means. If the stator winding of a single-phase induction motor is excited and the rotor is rotated by an auxiliary means and the starting device is then removed, the motor continues to rotate in the same direction in which it is started. The double revolving  field theory  is suggested to analyse the performance of a single-phase induction motor. It explains why a torque is produced in the rotor once it is turning. Double Revolving Field Theory According to the double revolving field theory of single-phase i...