These capacitors are designed to replace the original capacitor that has failed. You must replace the part as the motor may simply not work, draw excessive current or have porr torque.
These are suitable for motors operating at up to 400VAC and common values are offered here. Please note it is important to choose the correct value for the motor otherwise the starting torque of the motor will change.
Two different packages are provided. For the higher valued capacitors it's necessary to use the different case style which provides the important AMP250A terminals and an inbuilt safety device.