How to Test a Relay: A Simple Process You Can Do from the Comfort of Your Home

Relays are essential to the operation of large machinery. They are in charge of managing the electrical system of heavy machinery. Relays may develop defects with time; at this point, testing is necessary. To properly handle your heavy equipment, this article will explain how to check relays with a multimeter and assist you in determining whether they need to be changed.

 

Understanding How Relays Work

It's crucial to comprehend a relay's operation before discussing how to check relays with a multimeter. Relays are electrical switches that typically have a set of contacts and an electromagnetic coil. An electromagnetic coil generates a magnetic field when an electric current flows through it. The contacts of the relay then open or close. This process will either allow or prevent the flow of current, thus fulfilling the function of controlling heavy equipment.

 

Tools Needed to Test Relays

Multimeter

Used to measure voltage, current, and resistance, a multimeter is essential for how to check relays with a multimeter.

Test Leads

Connects the multimeter to the relay.

Relay Wiring Diagram

Helps you to connect and understand the relay pins correctly.

 

How to Test a Relay?

1. Disconnect Power

Before starting any tests, first, make sure that the power to the heavy equipment is disconnected. This protects your equipment and also ensures your safety during testing.

 

2. Finding Relay Locations

According to your equipment manual, locate the relay that needs to be tested. Typically, the relay is located near the control panel, or it may be covered by a protective cover. You will need to carefully remove the protective cover to locate the relay.

 

3. Check the appearance of the relay

Before performing an electrical test, first check the appearance of the relay. Look for burn marks and for broken coils. Finally, look for rusted contacts. These are signs that the relay is malfunctioning. This is also a sign that prompts you to replace the relay.

 

4. Test the resistance with a multimeter

How to check relays with a multimeter? Set your multimeter to resistance measurement mode. Locate the coil pins of the relay and connect the multimeter's test leads. Normally, you should see a certain resistance value. Generally, the resistance value of the relay should be between tens and hundreds of ohms. If it reads infinity, this means the coil is disconnected.

 

5. Testing the contacts for continuity

Next, you need to test the contacts of the relay. Set your multimeter to resistance measurement mode and connect to the normally open (NO) and common (COM) pins of the relay. If the relay is not energized, you should see a resistance value of infinity. When you apply voltage to energize the relay coil, the multimeter should show a resistance value close to zero. This indicates that the contacts are closing properly.

 

6. Testing the operation of the relay

Finally, continue to test the relay for proper operation by connecting an external power supply to the coil pins. Listen for the relay to make a “clicking” sound, which indicates that the relay is switching. If there is no sound or the operation fails, the relay is damaged and needs to be replaced.

 

Summary

Testing a relay is not a complicated task. By following the steps outlined above, you can easily check the working condition of your relays. Remember, regular inspection and maintenance of your relays can prevent many potential problems.

 

If you find a problem with your relay, or if you need to purchase a new relay, the MyMROmarts store has superbly crafted relays for sale. Visit the MyMROmarts online store today to find the right relay for your heavy equipment model!

 

By the end of this article, you should have a clearer understanding of “how to check relays with multimeter”. Hopefully, this information will help you feel more confident in handling relays during routine maintenance!