Asynchronous motor reverse braking control circuit

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An asynchronous motor can be subjected to back-emf braking after its power supply phase sequence is changed. At this point, when the phase sequence changes, the rotating magnetic field of the motor reverses direction; as a result, the torque generated by the motor is in the opposite direction to before, thereby enabling braking. When SB1 is pressed, the contactor KM1 closes, causing the motor to drive the speed relay KS to rotate as well. When the speed reaches the rated speed, the normally open contact of KS closes, preparing for braking. When the stop button S is pressed, KM1 loses power and its normally closed contacts close. Due to the inertia of the motor, the contacts of KS remain closed as well. At this point, KM2 is activated, causing reverse braking of the motor. When the motor’s speed drops to zero, KS opens and KM2 releases, thereby ending the braking process. Reverse-phase braking of the motor results in a brief reversal phenomenon.