ZnO Varistors in Brushless Motor Protection Circuits?

ZnO (Zinc Oxide) varistors are adjustable, non-polar resistors with instantaneous response capability. When voltage or current exceeds a certain threshold, their resistance rapidly decreases, absorbing overvoltage and overcurrent to protect brushless motors and related components from damage. In the protection circuit of brushless motors, ZnO varistors can be used to suppress transient disturbances such as overvoltage and overcurrent at the motor output, thereby safeguarding the brushless motor and its associated devices.

In the protection circuit of brushless motors, ZnO varistors are typically installed at the motor's input or output terminals and used in conjunction with other protective components like TVS (Transient Voltage Suppressor) diodes to collectively suppress transient surges of overvoltage and overcurrent. Additionally, to enhance the effectiveness of ZnO varistors, the following considerations should be taken into account:

1. Select the appropriate voltage-dependent resistance value: Choose a ZnO varistor with a suitable voltage-dependent resistance based on the operating voltage and current of the brushless motor.
2. Ensure sufficient power rating: In the protection circuit of a brushless motor, the ZnO varistor should have a sufficiently high power rating to prevent burnout or overload.
3. Optimize circuit layout: During circuit design, the layout should be optimized to minimize electromagnetic interference.
4. Pay attention to electrostatic protection: As a protective component, ZnO varistors also require electrostatic protection to avoid damage from external electrostatic interference.

In summary, ZnO varistors hold significant application value in the protection circuits of brushless motors, playing a crucial role in safeguarding the motor and its related components.