Working Principle:

The speed of a DC motor is inversely proportional to the magnetic field, and once the magnetic field is less than the minimum allowable value. The speed of the motor will exceed the maximum allowable value. Therefore, an overspeed switch is installed on the shaft of a DC motor, which relies on an internal centrifugal mechanism to trigger the motor overspeed signal when the contact of the switch is activated beyond a certain speed.

Due to the inverse relationship between the speed and magnetic field of a DC motor, if the magnetic field is less than the set minimum allowable value, the motor speed will exceed the maximum allowable value. At this time, an overspeed switch will be installed on the shaft of the DC motor. This overspeed switch is mainly based on its internal centrifugal mechanism. After the self flowing motor exceeds a certain speed, the contact action of the switch sends a signal of motor overspeed, which can be used to brake the mechanical brake or apply current in the opposite direction.

The overspeed switch works by utilizing centrifugal force. When the speed reaches a certain value, the centrifugal force acts to open the switch.

A single-phase capacitor motor has a speed switch connected to the starting winding circuit. When starting, the speed switch is closed, and the starting winding with capacitors in series is connected to the power supply. When the motor speed rises to a certain speed, the speed switch opens and the starting winding is cut off.