Input power of AC coil

- Dec 27, 2019-

Input power of AC coil

In order to make the relay work stably, apply rated voltage to the coil. If a voltage is applied (continuously) to the coil, which cannot make the relay fully operate, the coil will generate abnormal heat, resulting in abnormal loss of the coil.

The best power supply voltage of AC type relay is sine wave, because the AC coil can suppress the beep better under the condition of sine wave. If the waveform is distorted or distorted, the suppression function can not be played well. The following figure shows examples of several common waveforms.


If there are motor, solenoid, transformer and other devices connected to the driving circuit of the relay, when these devices work, the voltage on the relay coil will be reduced, which will cause the contact of the relay to vibrate, resulting in the contact adhesion, abnormal loss, or impassability. When a small transformer is used or a transformer without sufficient capacity is used as the power supply and the wiring is long, or the wiring for household and store is thin, similar phenomenon of coil voltage reduction will occur. In case of similar fault, please use synchronous oscilloscope for detection and correct adjustment.

If the motor and other loads with large variation are used, please separate the drive circuit and power circuit of the coil according to the purpose.

If the AC relay can not work stably, the AC can be converted to DC, and then the appropriate DC relay can be selected.