A motor protection reactor is installed between the drive and the motor, acting as a buffer to help protect the motor from electrical stress caused by the drive output.

 

A standard Pulse Width Modulated (PWM) drive converts the waveform into a square-wave-like form with sharp edges during switching transitions and transmits it to the motor. The drive generates a usable waveform to control the motor speed. Since the rise times of IGBTs during switching are in the nanosecond range, overvoltage peaks may occur due to switching, even when the drive-to-motor cables are kept as short as possible.

​

These voltage peaks may cause motors to overheat or malfunction. Drive output reactors, also known as dV/dt output filter reactors, help reduce high-voltage peaks caused by the cables between the drive and the motor. Motor protection reactors are commonly used with motor drives, uninterruptible power supplies, solar inverters, and active harmonic filters.

​

Benefits of Motor Protection Reactors

​

• They suppress voltage spikes and reduce them to a tolerable level.

• They reduce the dV/dt value.

• They improve motor operating efficiency.

• They reduce motor noise.

• They extend the service life of the motor by helping prevent overheating.

• They make it easier to operate the motor, even when long cable lengths are used.

​

Conclusion

​

Motor protection reactors act as a buffer between the drive and the motor. They smooth the sharp-edged waveform produced by the drive and reduce voltage stress on the motor. By conditioning the waveform to a more suitable profile, they help prevent overheating of the motor and supply cables, while also reducing stress on the drive’s current-carrying components.