Run capacitors are capacitors usually designed for continuous duty, and they are energized the entire time the motor is running. Run capacitors are rated in a range of 1.5?100 microfarads (µF or mfd), with voltages of either 370 V or 440 V. A capacitor is required in Single phase electric motors to energize a second-phase winding. Selecting the correct run capacitor is important. If the wrong run capacitor is installed, the motor will not have an even magnetic field. This can cause the motor to become noisy, increase energy consumption, cause performance to drop, and cause the motor to overheat.