Argon Distributors – How to test a motor start or run capacitor
Ensure your Multimeter has capacitance testing mode, this is usually shown as two vertical white lines like this -||- Set selection dial to this mode. Ensure leads are in common and test locations.
Remove capacitor from motor. (Registered electrician only) Touch your test prongs onto either lead or terminal.
Leave on test (multimeter may take 5-10 seconds for reading to settle down) The reading value should show the capacitor value. The capacitor should be replaced if this value is +/- 5% of value shown (Photo B shows a 15uf capacitor)
Note a motor start capacitor will have a higher microfarad (uf) value than a run capacitor and not all multimeters can test these, the meter may show zero value in this case but capacitor may still be within range.
If the meter shows a different value from capacitor rating or shows signs or heat or physical damage it must be replaced to ensure correct motor operation.