One of the AC contactor low voltage starting circuits

When the grid voltage drops below 85% of the rated voltage of the AC contactor's attraction coil , when the contactor is started, its armature
will beat and cannot be reliably closed. If the start-up time is long, the coil may be burned. For this purpose
, a diode can be connected in series with the AC contactor control circuit to change the DC start to AC operation.
    The circuit is shown in Figure 6-20. Since the release voltage of the AC contactor is below 40% to 65% of the rated voltage, the contactor will not trip again
due to low power supply voltage after closing .
This kind of control circuit can also achieve reliable pull-in when
the rated voltage of the coil of a small-capacity AC contactor is 380V and drops to above 240V: when the rated voltage of the coil is 220V and drops to above 150V, it can also
achieve reliable closing. Reliable suction.