Single Phase Motor (230 Volts)

You can also try two or multiple capacitors in parallel.for example 2 caps of 2 MFD in parallel will make 4 MFD.

Always insure that that voltage rating is equal or more than specified.

There are suppliers that offer an overnight service. Order two.

The motor with the smaller cap will be slightly slower and overheat.....the motor with the larger cap will run faster and overheat....neither is good....and don't depend on ratings to be accurate, get a good capacitor tester and verify the actual capacitance of any capacitor you install....learn to test motors by operating temperature with a good infrared temperature gun....usually when a motor capacitor goes bad the motor is failing...If you can get the motor operating at a proper temperature, it's usually a sign that you have the pf balanced....but if the bearing is failing, then the motor must be replaced or rebuilt....

you have a PSC motor, perm split capacitor

I trust that you are FULLY aware that "motor start" and "Motor run" are specific caps for single phase AC motors only. They are not just any old caps....

I noticed that nobody mentioned that exactly and I just wanted to be sure.

Even caps for start only (not your case) are not usually as higher quality as those for starting and running. Make sure you get one rated for both....

As already mentioned, you need the exact correct value of cap, which could be two in parallel (adding up to the required, in your case 2 x 2µF = 4µf), if the exact correct value is not available.....

That will actually improve the cooling of the caps slightly as well.....

But do make sure that you match the colour coded wiring for each cap, or identify the same connector pole for both and connect them - same pole to same pole in parallel......

Having the right value and type of cap precludes these sorts of problems of course....

Do not even think of using something else......

Check carefully that the cap you fit is also the "run" type, do NOT just believe the seller......

Use 2 8 mfd in series, that is 4 mfd. The total voltage of the 2 caps has to be equal to or greater that the original cap. -- JHF

It depends on the application.

The capacitor is sized per design to provide the proper torque for the specific motor application.

Changing the capacitor size will move the motor torque curve and it could result in motor failure.

If the torque curve of the motor is critical you may experience motor winding and/or capacitor heating issues and it could lead to motor failure.

This is not quite true. The capacitor is sized to phase shift the current the correct phase angle for the run or start condition. The topology of the stator phase winding will determine what phase angle is desired. When the capacitor is incorrectly sized the motor torque will drop since the stator field timing will be incorrect.

My point is the motor design is what defines the maximum torque a motor can produce. With an improperly sized capacitor the optimum torque will not occur.