Precautions for braking motor inverter speed control

Publish Time:

2020-12-17

With the popularization of industrial automation, the application of variable frequency drives is becoming increasingly widespread, and the speed control of motors by variable frequency drives is also becoming more common. Motors controlled by variable frequency drives should use special motors for variable frequency speed regulation, running stably at the set speed, while special braking motors for variable frequency speed regulation are designed to meet the requirements of braking motors under variable frequency speed regulation conditions.

With the increasing prevalence of industrial automation, the application of variable frequency drives (VFDs) is becoming more widespread, and the use of VFDs for motor speed control is increasingly common. Motors controlled by VFDs should use dedicated motors for variable frequency speed control, operating stably at the set speed, while dedicated braking motors for variable frequency speed control are designed to meet the requirements of braking motors under variable frequency speed control conditions.

After prolonged use, the stator windings of ordinary motors are prone to aging, leading to motor breakdown and rendering them unusable. Low-frequency speed control, in particular, results in low motor speeds and significantly reduced cooling efficiency, hindering heat dissipation and potentially causing damage with prolonged operation. Dedicated VFD motors utilize dedicated stators and rotors, specialized winding wires and leads, and a cooling fan with an independent power supply at the motor rear, ensuring good heat dissipation even at low speeds. Therefore, using dedicated motors for variable frequency speed control with VFD-controlled braking motors ensures long-term durability.

Precautions for Using Braking Motors

1. At low speeds, the motor fan speed is low, and the heat generated by the motor cannot be dissipated quickly, preventing continuous use for extended periods.

2. Disconnect the brake from the motor terminals and connect it separately to the power supply.

3. When exceeding the rated frequency of the motor, the fan speed increases, and the high-speed rotation of the fan blades consumes some power, reducing the motor's output power; it can only be used at reduced power.

4. When using a VFD to control a braking motor, ensure the brake is synchronized. During startup, when the motor starts via the VFD, the brake is energized; during braking, the VFD quickly reduces the motor speed. When the motor stops rotating, the brake is de-energized and the motor is braked. When the inverter controls the motor, the timing of energizing and de-energizing the brake is crucial.

When a motor with a brake is controlled by a VFD, the brake is synchronized. Methods to check for synchronization:

1. After normal operation of the equipment, check the motor rear for any burning smell;