How Does The Power Fittings Use A Voltmeter To Test The Pull-in And Release Voltages Of The Ac Contactor?

Gas filled cabinet How to use a voltmeter to test the pull-in and release voltages of an AC contactor?
In some places where the power supply voltage is low, if the rated pull-in voltage of the AC contactor coil is high and the release voltage is low, it will affect the normal operation of the AC contactor. Therefore, it is necessary to perform this test.
The operation method is to adjust the voltage regulator TA to the 0V position, close the switch QS, and slowly adjust the voltage regulator handwheel. The pointer of the voltmeter PV gradually rises. When you hear the contactor close with a "click", the value indicated by PV is the pull-in voltage; then adjust it back, and when you hear the contact release with a "click", PV indicates the release voltage.