Air Compressor CAPACITORS

[MasterSolenoid]

I was at a neighbors house last Week.
He said when he plugs in his 45 year old Craftsman Air Compressor, the motor will lug and it will trip the breaker.
Worst case scenario, he was going to buy a 'new' compressor.

I saw the motor had two large Capacitors and suggested we check them.
I used my Multimeter that shows microfarads. / Problem: one of the Capacitors was not releasing its charge.
Ordered replacement capacitors ( $25.00 total) and installed.
The moment of truth arrived, and I was nervous . . . . Success, it ran fine.
As a home owner, this was my first experience diagnosing a bad Capacitor and replacing.

Moral of the story: Know that electric motors have Capacitors and learn how to check them.
1) visual (leaking oil, bulges)
2) actual microfarad reading (listed on capacitor)
3) able to release its charge

Warning: DO NOT touch contacts unless you discharged them.

Hope this info helps someone.

 

[Kawiguy454]

...Also in ceiling fans. when they start to buzz it is not a bad fan but the capacitor. Replace capacitor and return it to like new silence.

 

[Dennywires]

you can use a bleed resistor to discharge the cap or an old insulated screwdriver.

 

[benjy]

good info for sure! i am not electrical savy buy can wire things per instructions. an attic vent fan died a while ago + looking at what was prolly a capacitor melted i replaced the unit inside the roof "hood" , last week my prolly 15 year old garage-attic vent died + i replaced it. there was a metal gizmo mounted by the motor capacitor i assume that looked good but the exterior of the motor was blackened. years ago i bought just the motor as my original house attic vent was a craftsman with parts list, today theres little info + people like me prolly overspend due to lack ok knowledge just replace everything $$$

 

[Lubener]

If you think about it, capacitors either short (rare) or will open. Either case, the capacitor is unable to store a charge. It may lose some capacitance but that usually will be enough to start and run a motor.They will have a discharge path in the circuit, usually through the winding of the motor. If you short across a capacitor and it discharges, there likely is an open circuit somewhere preventing the capacitor to discharge its energy after power shutdown. I do agree for safety sake to bridge a capacitors leads with a screw driver to be on the safe side.