What does a braking resistor do on a Schneider Electric Altivar Drive?


20 May 2021

By using a braking resistor, the drive can dissipate energy into the brake increasing the available braking torque and power to the load thus producing faster and more controlled braking of your motor. 

To ensure that the braking resistor is in operation - Select the appropriate braking resistor using the associated drive catalogue. Connect the braking resistor between PA and PB terminals. BRA parameter otherwise known as dec.ramp adapt  should be set to NO. This allows the DC bus voltage to rise to the threshold at which the braking transistor fires. The above figure shows a scope of the DC bus voltage, motor speed &  torque as well as the current flowing in the braking resistor, for a complete machine cycle.