The supplier of the frequency converter feedback unit reminds you that the method of quickly stopping the motor by giving it an electromagnetic torque opposite to the actual direction of rotation while cutting off the power supply. The most commonly used methods are energy consumption braking and reverse braking.
1. Energy consumption braking
The method of generating a static magnetic field by cutting off the AC power supply to the motor and supplying any binary sum of DC power to the stator winding, relying on the inertia rotation of the rotor to cut and modify the static magnetic field and generate braking torque.
2. Reverse braking
The method of changing the power phase sequence of the stator winding of the motor while cutting off the normal operating power supply, so that it has a tendency to reverse and generate a larger braking torque. The essence of reverse braking is to make the motor want to reverse and brake. Therefore, when the speed of the motor approaches zero, the reverse braking power supply should be immediately cut off, otherwise the motor will reverse. In practical control, a speed relay is used to automatically cut off the braking power supply.
3. Power generation feedback braking
When the speed of the electric motor exceeds the speed of the rotating magnetic field, the direction of the electromagnetic torque is opposite to the direction of the rotor's motion, thereby limiting the rotor's speed and playing a braking role. Because when the rotor speed is greater than the rotational speed of the rotating magnetic field, electrical energy is returned from the stator of the motor to the power source, and in fact, the motor has already switched to generator operation. Therefore, this type of braking is called power generation feedback braking.