The working principle of the electromagnetic vibrator indicates as shown in the figure. In the electromagnetic vibrator there is an electromagnetic coil, through the electromagnetic coil of the current is through the half-wave rectifier of the pulse current.

In the positive half wave, the current passes through, the electromagnet has suction, attracts the vibrating plate close; In the negative half wave, no current passes through, the electromagnet suction disappears, because of the spring action, the vibrating plate is back to the original position, and the coal groove is connected with the vibrating plate, so that under the action of the electromagnetic vibrator, the coal trough will continue.