Remember to choose a capactor whose voltage rating is at least equal to the rated voltage of the motor. It's perfectly fine to use a capacitor whose voltage rating is greater than the motor's voltage. For example if your motor runs at 220V your capacitor's voltage rating must be 220V or larger. A 330V rated capacitor is fine.
These electric motors use a capacitor to start and run the motor efficiently. We also explain the choice & wiring procedures for a hard start capacitor designed to get a hard-starting air conditioner compressor motor, fan motor, refrigerator, or freezer compressor or other electric motor (such as a well pump) going.
Select a replacement capacitor whose capacitance value in µF, (micro-farads) typically expressed as a range such as 30 µF - 50 µF matches the original capacitor and/or the data tag on your electric motor. The voltage rating of a capacitor indicates the highest nominal voltage at which it is designed to operate.
What They Are: Specifically designed for motors, start and run capacitors serve different roles but are both crucial in single-phase motors. Start capacitors help the motor kick off with a burst of energy, while run capacitors stay engaged during operation to maintain efficiency.
Typical Motor Driver Board Showing Large Bulk Capacitors Experienced engineers often use general guidelines about bulk capacitance to select the capacitor values. One such guideline says to use at least 1 to 4μF of capacitance for each Watt of motor power.
ON the capacitor body you'll see a voltage range like the one you cite - 250v 150uF start capacitor. - that 250-V is the maximum voltage the cap can handle; you're OK using it at lower voltage that matches your motor's data plate. I am refurbishing an old (about 40 yrs old) press drill. The electric motor is single phase and runs off 240v.