Dynamic Braking Resistors

 Dynamic Braking Resistors

The drive manufacturer normally determines the power rating (watts) needed to prevent overheating during braking duty. The peak braking current is determined by the specified resistance value. Each drive manufacturer specifies a resistance range with a minimum to prevent overcurrent and damage to the drive and a maximum value to give adequate lower dissipation capability.

Dynamic Braking Resistors that can be delivered quickly, completely assembled, and ready for convenient installation. Dynamic Braking Resistors are used with AC VFD’s to produce a braking torque in the motor during overhauling conditions. The dynamic braking resistor is connected across the DC bus and will see voltages as high as 800 volts.

When the motor serves as a generator (rotating at speeds higher than the synchronous speed), the generated energy by the motor increases the voltage in the DC bus of the motor drive. In order to limit this increased voltage to protect the equipment, DC bus voltage must be limited under a critical value. As feeding this energy back to grid is not an economical method due to need of expensive power electronics and control equipments in most cases, this excess energy is converted into heat through a brake chopper and a braking resistor. Braking resistors provide compact and economical solution for dissipating the excess energy produced by the motor.

Dynamic Braking Resistors made to last .