AC Run Capacitors: What Are They And Why Do They Fail?
You've probably heard about your AC's start capacitor. Nearly all residential air conditioners use a start capacitor to provide the initial power necessary to get the compressor moving. This capacitor stores energy while the capacitor is off, preventing an excessive load on your home's electrical system and minimizing the likelihood of a tripped breaker.
However, some air conditioners use two capacitors. This second capacitor, known as a run capacitor, serves a much different purpose.