Kung Fu Maintenance explains the role and purposes of capacitors in air conditioner systems.
OK right here what we have is a capacitor. The electricity comes in in a wave for and what the cap does is it translates that wave form into a specific pulse pattern. Similar to like Morse code would be code well this particular pulse pattern is what works well for the compressor.
This is your run capacitor. This particular one is a 35 microfarad capacitor. You always want to use the same rated capacitor for the system that you are working on.
As far as the voltage on the cap this particular one is I think a 370 volt. You can go up in voltage you just can’t go down in voltage when you use a cap. You always want to use the same microfarad capacitor.
Now this little capacitor is a start cap for the fan. The fan motor is kind of funny in that it can’t start on its own. When the power comes in, the power can’t start it on its own and what the start capacitor does is it kicks it off so that the fan can start spinning.
Now if you came up here and you saw that you turned your unit on and the compressor turned on and the fan motor wasn’t turning on. Sometimes you can give the fan a little push. Sometimes with a pen or screwdriver or something and if it kicked on. That would mean that your start capacitor was bad and that it is time to replace this little capacitor.
Now sometimes you will see these capacitors, now I will try to find a photo and put it on this video, where there will be three ports on the cap and one of them will be for the fan cap. It is just an alternate way of wiring this here. Where the common is internal to the run cap with a start cap. Now this particular fan cap is a five microfarad capacitor. Again you always want to use the correctly rated cap for your systems.