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How to Replace One Run Capacitor With Two

The run capacitor on a single-phase electric motor shifts the auxiliary or start winding of the motor out of phase with the main winding. If the run capacitor fails, replacement is required. Sometimes an exact replacement is unavailable, and two capacitors, both of a lower value than the original, are wired in parallel to replace the original. The capacitance values of the two capacitors add together. The voltage rating of both new capacitors must equal or exceed the value of the original.

Things You'll Need

Screwdriver
Wire
Wire stripper
Run capacitors

Instructions

- 1
  Disconnect the motor from the power source by unplugging it, or by turning the motor disconnect switch or the circuit breaker off. Place the tip of the screwdriver on one terminal of the existing run capacitor and bring the shaft into contact with the other terminal to short it. This ensures that the capacitor is discharged.
- 2
  Loosen the terminals on the existing run capacitor with the screwdriver and remove the motor wires.
- 3
  Cut two pieces of wire to connect the two new replacement run capacitors. Strip the ends of each wire with the wire stripper just enough to make the connections.
- 4
  Loosen the terminals on the new capacitors. Connect a new wire between a terminal on one capacitor to a terminal on the other capacitor. Repeat this with a second wire between the two remaining capacitor terminals.
- 5
  Connect one motor wire to a terminal on one capacitor and the other motor wire to the other terminal on the same capacitor. Tighten all the terminals securely with the screwdriver. The two capacitors are wired in series.

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