How To Test A Capacitor
This short video shows How To Test A Capacitor. Capacitors for air compressors can be tricky due to the nature in size and the different ratings. We give a brief explanation here. If in doubt, then always check your manual or call the manufacturer for information.
How to Test a Capacitor
1. Disconnect capacitor from motor and discharge with insulated screwdriver across terminals.
2. Set your ohmmeter to highest scale; connect one lead to each terminal on the capacitor.
3. If needle drops to zero and stays at zero, capacitor is probably shorted.
4. If needle remains at a high value, capacitor is probably open.
5. If needle drops to zero and slowly rises, capacitor is probably good. You may also troubleshoot capacitors by means of a simple "Capacitor Tester" which generates an audible sound for testing.
Note: Master Tool Repair claims no responsibility for injury, dismemberment or accidental death. This document is for information purposes only and all testing performed using this material is at the discretion of the individual performing this test.
Recent Posts
-
Just Got a New Air Compressor Pump? Master the Air Compressor Break-In Process!
Congratulations! You’ve just upgraded your setup with a high-quality replacement pump. Whether you’r …Feb 17, 2026 -
Fix Low Pressure and Slow Fill: A Practical Troubleshooting Guide
Is your air compressor taking forever to reach "cut-out" pressure? Low pressure and slow fill times …Feb 10, 2026 -
What’s That Hiss? Demystifying the Unloader Valve’s Role
If you own an air compressor, you’ve heard it: that sharp psshhh sound the moment the motor shuts of …Feb 3, 2026