Three Operating States of Induction Motors And Their Judgment Methods!

The three operating states of the induction motor are the motor operating state, the generator operating state and the electromagnetic braking operating state.

Here is the list

The running state of the induction motor

The running state of the induction motor

Electromagnetic brake operating status

The running state of the induction motor

After the stator of the induction motor is powered on, a rotating magnetic field is generated in the air gap and rotates at a synchronous speed n1. Through electromagnetic induction, electromagnetic torque is generated to act on the rotor, and the rotor rotates under the action of electromagnetic torque. At this time, the motor inputs electrical energy from the stator side and outputs mechanical energy from the rotor side. This operating state of the induction motor is called the motor operating state. As the motor running state, the condition of 0<n<n1 or 0<S<1 must be satisfied.

The running state of the induction motor

If the rotor of the induction motor is dragged by the prime mover and accelerated in the direction of the original motor running state, when the rotor speed n is higher than the synchronous speed n1, that is, n>n1, the air gap rotating magnetic field cuts the rotor strip the same as the motor. In the operating state, the direction of the induced potential and current in the rod is also opposite to the direction of the generated electromagnetic torque. In this case, the electromagnetic torque is the braking torque of the prime mover. The motor rotor continues to rotate, and the prime mover must input mechanical power to the motor. On the other hand, due to the change of the rotor current direction, the stator current direction also changes, so the stator side no longer inputs electrical energy from the grid, but outputs electrical energy to the grid. In this way, the operating state of the induction motor is that mechanical power is input from the rotor side and electrical energy is output from the stator side. This operating state of converting mechanical energy into electrical energy is called the generator operating state of the induction motor. As the running state of the generator, the condition of n>n1 or S>1 must be satisfied.

Electromagnetic brake operating status

If the rotor of the induction motor is dragged by the external torque and rotates against the direction of the original motor running state, the direction of the induced electromotive force and current in the rotor is still the same as the direction of the original running state of the motor. The direction of the torque is the same as that of the original motor, but it is opposite to the direction of the rotor, that is, opposite to the direction of the applied torque. At this time, the electromagnetic torque becomes the braking torque. To overcome this braking torque and maintain continuous rotation of the rotor, the applied torque must provide mechanical power to the rotor. In this way, the induction motor receives electrical power from the stator and mechanical power from the rotor. This operating state of the induction motor is called the electromagnetic braking operating state. As the working state of the electromagnetic brake, the condition of n<0 or S>1 must be satisfied.

Hangzhou New Hengli Electric Machine MFG. Co., Ltd.  works has been named the provincial advanced enterprise by Zhejiang provincial government and become a state grade-2 enterprise in 1988.

Hangzhou New Hengli Electric Machine MFG. Co., Ltd.  works has been named the provincial advanced enterprise by Zhejiang provincial government and become a state grade-2 enterprise in 1988.