How To Test Contactor

Testing a contactor is a relatively easy process. The first step is to make sure the power is off to the contactor. Next, remove the wires from the contactor terminals. Use a continuity tester to test for continuity between the contacts and between each contact and the coil. If there is no continuity, the contacts are bad and need to be replaced. If there is continuity, the coil is good and the contacts can be reinstalled.

How To Test Contactor

A contactor is a device that uses a small amount of current to control a larger amount of current. A contactor is often used to switch on or off a large electrical load, such as a motor. Contactor coils are usually rated for 240 volts AC, but can be used with DC voltages. To test a contactor, you will need an ohmmeter. Set the meter to the R x 1 setting and touch the probes to the two terminals on the contactor coil

below voltmeter, screwdriver, contactor

  • Close the main circuit breaker and test the contactor for continuity with a multimeter
  • Check that the contacts open and
  • Check that the contactor is properly installed and the correct voltage is being supplied to it

below -Check the contactor for continuity with a multimeter. -Check the contactor for proper operation by energizing it with a small current. -Check the contactor for proper operation by energizing it with a large current.


Frequently Asked Questions

What Should A Contactor Coil Read?

A contactor coil should read a resistance of about 5-10Ω when it is not energized, and it should read a resistance of 0Ω when it is energized.

How Many Ohms Should A Contactor Have?

A contactor should have an impedance of about 10 ohms.

Should A Contactor Have Continuity?

Yes, a contactor should have continuity. If it doesn’t, it can create an unsafe condition.


In Summary

A contactor is a device that is used to control the flow of electricity to a load. It is important to test a contactor before installing it to ensure that it is in good working condition. There are several ways to test a contactor, including Ohm’s law, continuity testing, and voltage drop testing.

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