When Does the DSY Series Servo Motor Require a Braking Resistor? Can a Battery Be Used to Absorb Bus Voltage?

For the DSY series low-voltage servo motors, the following explanation clarifies whether an external braking resistor needs to be installed.

Two key conditions require installation:

1. When your application involves frequent emergency stops, rapid start/stop cycles, or large-inertia loads undergoing fast deceleration.
2. When the system’s bus voltage rises and consistently exceeds 74V.

The most reliable approach is to perform actual measurements under real operating conditions. During actual equipment operation, you can use servo debugging software to monitor the peak value of the DC bus voltage in real time. If the voltage frequently exceeds 74V, an appropriate external braking resistor must be installed to dissipate regenerative energy and ensure system stability.

Important Note:

Never use batteries such as lithium batteries to absorb this energy. Battery charging management is incompatible with the instantaneous high-power energy backflow characteristics of servo systems and can easily cause malfunctions or safety risks. Energy dissipation must be carried out exclusively through a dedicated braking resistor.

In summary, we recommend testing and collecting data under actual operating conditions to determine the braking resistor configuration based on whether the bus voltage exceeds 74V and the system’s operational characteristics. This is the best practice to ensure reliable system operation.

Updated on: 30/01/2026