Function of the Servo Motor Braking Resistor

Simply put, the core function of the braking resistor is to dissipate the excess energy generated by the servo motor during rapid braking or deceleration, thereby maintaining system voltage stability and protecting the drive from damage.

For our servo motors currently sold:

• The DSY series does not come with a built-in braking resistor and requires an external one. The resistor specifications are shown in the figure below.

• The A6 series (400W and below) does not come with a built-in braking resistor. The resistor specifications are shown in the figure below.

• The T6 series 100W model does not come with a built-in braking resistor. The resistor specifications are shown in the figure below.

• The T6-100RS allows a minimum resistance of 50Ω, with a recommended minimum power of 50W.

Key Points:

1. Essential for Rapid Start-Stop Applications: In applications requiring rapid starts and stops, it is best to add a braking resistor. If this is not possible, the acceleration and deceleration times must be set long enough. Especially under high load with high-speed starts and stops, the motor generates significant back EMF (regenerative energy) that must be dissipated by the braking resistor.

2. Generally Not Considered for Stepper Motors: Stepper motors typically operate at lower speeds, and their system design does not account for a braking resistor. Therefore, in high-load, high acceleration/deceleration scenarios, the back EMF they generate cannot be dissipated internally.

3. Strictly Prohibit Disabling During Operation: For stepper motors or servo systems without a braking resistor, it is strictly forbidden to suddenly disable the drive while the motor is running. Even systems with a braking resistor should avoid this improper operation. The back EMF generated by the motor's rotational inertia cannot be dissipated promptly, which can easily cause overvoltage damage to the drive.

Conclusion: In high dynamic response servo applications, correctly selecting and configuring a braking resistor is a necessary measure to ensure stable system operation and prevent drive damage.

Updated on: 30/10/2025