CHECKING CONDITION OF RELAY

Relays are discrete devices (as opposed to integrated circuits) that are used to allow a low power logic signal to control a much higher power circuit. The relay isolates the high power circuit, helping to protect the lower power circuit by providing a small electromagnetic coil for the logic circuit to control.

Supplies and Materials  

• Relay 

Tools and Equipment 

• Multitester

• Personal protective equipment 

          - gloves
          - goggles

Procedure   

1. Prepare the necessary tools, materials, equipment and personal protective equipment (PPE) in performing the activity.

2. Wear the appropriate PPE.

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3. Consult the relay schematic or data sheet. Relays have fairly standard pin configurations, but it is best to search for the data sheets to find out more about the number of pins from the manufacturer, if available. Typically, these will be printed on the relay.

• Information on current and voltage ratings, pin configurations, and other information is sometimes available in the datasheets will be invaluable in testing, and eliminate most errors associated with testing. Testing pins randomly without knowing the pin configuration is possible, but if the relay is damaged, results may be unpredictable.

• Some relays, depending on their size, may also have this information printed directly on the body of the relay as well.

4. Set the multitester to range X1 to X10.

5. Connect the test probe of the multi tester to the terminals of the chime (See the terminal marking of chime). Zero or low resistance reading shows that the coil terminal of the buzzer is shorted, no reading means open. If the reading shows 6 – 60 ohms value, the coil is good.

6. Connect the test probe to normally open terminal of the relay (30 87), high         resistance shows that contact is good

7. Then, connect the test probe to the normally closed contacts (30 87a), low resistance shows that the contact is good.

Introduction to Ice Cube Relays