Measuring contact resistance
Use the resistance profile of the universal meter to measure the resistance of the normally closed contact and the moving point. The resistance value should be 0, (the contact resistance can be measured in a more accurate way within 100 milliohms); while the normally open contact and the moving point The resistance of a point is infinite. From this, it can be distinguished which is a normally closed contact and which is a normally open contact.
Measuring coil resistance
The resistance value of the relay coil can be measured with the universal meter R×10Ω, so as to judge whether the coil is open.
Measure pull-in voltage and current
Get an adjustable regulated power supply and ammeter, input a set of voltage to the relay, and connect an ammeter in series in the power supply circuit for monitoring. Slowly increase the power supply voltage. To view more content, please log in to Haohua Diantong. When you hear the sound of the relay, write down the pull-in voltage and pull-in current. For accuracy, you can try several times and find the average value.
Measure release voltage and current
The connection test is also like the above. When the relay pulls in, then gradually reduces the power supply voltage. When you hear the relay release sound again, write down the voltage and current at this time. You can also try several times to get an 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 unreliable.
