Relay test

1, measuring contact resistance
With the universal meter's resistance file, measure the normally closed contact and the moving point resistance, the resistance value should be 0; and the resistance value of the normally open contact and the moving point is infinite. This can distinguish the normally closed contact, which is the normally open contact.

2, measuring coil resistance

The universal table R×10Ω can be used to measure the resistance of the relay coil to determine whether there is an open circuit in the coil.

3, measuring the pull-in voltage and pull-in current

To find adjustable power supply and current meter, input a set of voltage to the relay, and in the power supply circuit in series to monitor the current meter. Slowly increase the voltage of the power supply. When you hear the sound of the relay, record the pull-in voltage and the pull-in current. For accuracy, try several times and average.

4, measure the release voltage and release current

The connection test is also performed as described above. When the relay is pulled in and then the supply voltage is gradually reduced, when the relay is heard to release the sound again, the voltage and current at this time are noted, and it may be tried several times to obtain the average release. Voltage and release current. Under normal circumstances, the release voltage of the relay is about 10~50% of the pull-in voltage. If the release voltage is too small (less than 1/10 of the pull-in voltage), it cannot be used normally, which will threaten the stability of the circuit. The work is not reliable.