The electric valve actuator is an important part of the automatic regulation system. It directly controls the delivery of materials or energy regulated media according to the command of the regulator. Its working principle is: the electric valve actuator takes the DC current as the control and feedback signal. When the upper instrument or computer sends a control signal, the electric actuator acts in proportion to the size of the signal, and opens the valve or damper to the corresponding opening through the output shaft, The system opening signal is fed back to the control room to complete the system regulation function.