Motors, Capacitors & Contactors

PSC vs. ECM, run and start capacitors, hard-start kits, contactors, relays, motor testing and locked-rotor faults.

5 guides

• Condenser Fan Motor Replacement and Getting Rotation Right
  How to spec and replace a condenser fan motor — matching HP, RPM, voltage, rotation, and shaft — and how to make sure the new motor turns the right way and moves air up and out the top.
• Contactors: Testing, Chattering, and Welded Contacts
  How a contactor works, how to test the coil and the contacts, and how to read the three classic failures — pitted/burnt contacts, a chattering coil, and welded contacts that won't release.
• Hard-Start Kits: When to Use One and How to Wire It
  What a hard-start kit actually does, the difference between a PTCR puck and a true start-capacitor/potential-relay kit, when a hard start is the right call versus a band-aid, and how it wires in.
• PSC vs ECM Blower Motors and How to Test Each
  The practical difference between PSC and ECM blower motors, what each one is doing, and how to actually test them in the field — including why you can't ohm out an ECM the way you would a PSC.
• Testing a Run Capacitor and Reading Microfarads
  How to safely discharge, identify, and test a run or dual-run capacitor, read its microfarad value against the printed rating, and interpret the terminals (C, HERM, FAN) on a single-can dual cap.

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