Dynamic Braking Resistors

Dynamic Braking Resistors are used with AC Variable Frequency Drives to produce a braking torque in the motor during overhauling load conditions. The dynamic braking resistor is connected across the DC bus and can see voltages as high as 800 volts (IPC DB Resistors are double insulated and rated for 1,000 volts). The resistance value in Ohms determines the amount of braking torque produced and thus the rate at which the motor will stop. This value must be within acceptable limits for the particular drive and application. The resistor wattage is sized to prevent overheating during normal braking cycles. High duty applications require larger (higher wattage rated) resistors. DB resistors are often added to prevent overvoltage trips on the drive when stopping the motor.

IPC Power Resistors International, Inc., 7453 Empire Drive, Unit 105, Florence, KY 41042-2923. Tel: 606-282-2900; Fax: 606-282-2904.