Single phase induction motor working principle
single phase induction motor is a single-phase AC power supply rotary motor, the stator winding is single-phase. When access to single-phase AC, it will produce an alternating pulsating magnetic field in the stator air gap, so the single phase induction motor can not be self-starting. In AC motors, the armature magnetomotive force is established when the stator windings pass an alternating current, which has a significant impact on the motor's energy conversion and operational performance. Therefore, the single-phase AC winding into the single-phase AC pulse magnetic pulse generated momentum, the magnetic momentum can be decomposed into two equal amplitude, opposite speed rotary magnetomotive force and thus in the air gap to establish forward and reverse Magnetic field and. These two rotating magnetic fields cut the rotor conductors and generate induced electromotive forces and induced currents in the rotor conductors, respectively.
Single phase induction motor current and magnetic field interaction produces positive and negative electromagnetic torque. Forward electromagnetic torque attempts to rotate the rotor forward; reverse electromagnetic torque attempts to reverse the rotor. The sum of these two torques is the resultant torque that drives the motor to rotate.
Whether it is forward magnetic field or reverse magnetic field, single phase induction motor size and slip relationship with the 3 Phase Induction Motor is the same. If the motor speed is n,
Then for the forward magnetic field, the slip is: s + = (n1-n) / n1 = s
For the reversal of the magnetic field, the slip is: s - = (- n1-n) / - n1 = s