A capacitor is an electric component that temporarily stores an electrical charge. A dual "run capacitor" supports two electric motors, such as in large air conditioner or heat pump units, with both a fan motor and a compressor motor. It saves space by combining two physical capacitors into one case. The dual capacitor has three terminals labeled "C", "FAN", and "HERM", which stand for the *C*ommon, Fan, and *HERM*etically sealed compressor.
Dual capacitors come in a variety of sizes, depending on the capacitance (µF or MFD), such as 40 plus 5 µF, and also the voltage. A 440 volt capacitor can be used in place of a 370 volt, as it is build better, but the 370 can't be used in place of a 440 volt. It will work for a while and will fail prematurely, as exceeding the capacitor's rated voltage will cause the dielectric to break down and the capacitor to short out. Same as an electric wire- 600V rated wire is better than 300V one .The capacitance(µF or MFD) must be the same or stay within +10% or -10% of its original value . Example: 50 µF cap can be substituted by 45 to 55 µF with the same or better voltage ratings capacitor . Round cylinder-shaped dual run capacitors are commonly used for air conditioning, to help in the starting of the compressor and the condenser fan motor.
You will ask "Why I need a Cap that is rated 440V in my A/C?"
Answer: You need to realize that a motor is an inductive device. When the supply voltage is applied to the motor run winding, the voltage across the start winding will be increased to a higher voltage value. A motor acts like a transformer with the run winding acting as the primary and the start winding acting as the secondary. This is why the capacitor has a much higher voltage rating than the 230 being the supply voltage.
If a Capacitor is not EIA-456-A approved means it is not approved for US market.
