Relays, Contactors and Starters


Description:

Explanation of troubleshooting techniques for relays, contactors, and starters used in the HVACR field

Learning Outcome:

Upon the completion of this module, you will be able to:

  1. Describe the basic components of a relay.
  2. Identify the four common faults you may encounter when working with relays.
  3. Explain the procedure for testing pilot-duty relays.
  4. Describe the features of a line-duty relay.
  5. Explain the procedure for testing line-duty relays.
  6. Describe the features of a contactor.
  7. Explain the procedure for testing contactors.
  8. Describe the features of a starter and a potential relay.
  9. Explain the procedure for testing starters and potential relays.
  10. Describe the features of current relays and time-delay relays.
  11. Explain the procedure for testing current relays and time-delay relays.

Topic 1: Relays

  • Topic Introduction and Objectives
  • Basic Components of a Relay
  • Common Faults
  • Check-Point Question
  • Topic Summary

Topic 2: Testing Pilot-Duty Relays

  • Topic Introduction and Objectives
  • Testing the Contacts
  • Testing for an "Open" Coil
  • Testing for a "Shorted" Coil
  • Calculating Current Draw of Pilot-Duty Relay
  • Check-Point Question
  • Topic Summary

Topic 3: Testing Line-Duty Relays

  • Topic Introduction and Objectives
  • Features of a Line-Duty Relay
  • Testing the Contacts
  • Testing for an "Open" Coil
  • Testing for a "Shorted" Coil
  • Check-Point Question
  • Topic Summary

Topic 4: Contactors

  • Topic Introduction and Objectives
  • Features of a Contactor
  • When to Replace a Contactor
  • Testing Contactors
  • Testing the Contacts
  • Testing for an "Open" Coil
  • Testing for a "Shorted" Coil
  • Check-Point Question
  • Topic Summary

Topic 5: Starters and Potential Relays

  • Topic Introduction and Objectives
  • Features of a Starter
  • Testing Magnetic Starters
  • Check-Point Question
  • Potential Relays
  • Potential Relays: Connecting the Terminals
  • Testing a Potential Relay
  • Testing the Coil of a Potential Relay
  • Using a Relay Tester
  • Testing the Relay in Operation
  • Check-Point Question
  • Check-Point Question
  • Topic Summary

Topic 6: Current Relays and Time-Delay Relays

  • Topic Introduction and Objectives
  • Features of a Current Relay
  • Connecting the Terminals on a Current Relay
  • Testing Current Relays
  • Features of a Time-Delay Relay
  • Testing a Delay-On-Make Relay
  • Testing a Delay-On-Break Relay
  • Check-Point Question
  • Check-Point Question
  • Topic Summary
  • Assessment