The YEJ series electromagnetic brake three-phase asynchronous motor is composed of a dc electromagnet brake on the basis of the Y series motor.

　　The excitation of the electromagnet is direct current, which is supplied by a transistor rectifier installed in the motor junction box. It is stipulated in JB/T6456 that the dc voltage of the motor with the center height of 112mm and above is 170V(the ac line voltage is 380V), while the dc voltage of the motor with the center height of 100mm and below is 99V(the ac y-connect voltage is 220V).

　　When the motor is connected with three-phase alternating current, the excitation coil of the electromagnet also gets the dc excitation voltage, which makes the electromagnet produce magnetic force, and the connecting suction merges to make the friction surface of the brake and the static friction plate want to break off. The motor starts to turn when it leaves the braking state.

　　When the power supply is cut off, the stator rotating magnetic field of the motor and the excitation current of the brake disappear simultaneously.

　　The friction coefficient of the friction plate and the pressure of the brake spring determine the magnitude of the friction static torque.

　　The release lever is used to make the brake in a non-braking state when the motor is not energized, which is convenient to check the flexibility of the motor rotor before testing or use.