The run capacitor is used to improve the running efficiency of a compressor motor. The run capacitor is placed in series with the start winding of the compressor and will remain in the circuit as the motor operates. As current flows through the run capacitor and the start winding, it causes a phase shift of the motors current, thus improving the power factor of the motor. Since the run capacitor remains in the circuit, it needs to be able to dissipate the heat generated by being in continuous operation. This is done by its design. The air compressor run capacitor is oil-filled to allow the capacitor to dissipate the heat generated. Whatever your need, requirement, and budget you can count on finding the right equipment at an affordable price at Rite Products.