I have a 5 hp Ajax single phase AC motor. When i got it the start and run caps were missing. Is there anyway to determine the proper start and run cap values based on the info on the nameplate? Thank You.
The preferable method would be to search the brand and model number to see if you can find detailed information from the manufacturer. You could also contact the manufacturer or a sales outlet for the manufacturer. The web sites of capacitor sellers sometimes have tables of typical values based on power, voltage and frequency ratings. Using a typical value should be adequate, but might have a small effect on motor performance. Check the motor current after replacement and check to see if the motor comes up to speed without too much delay. Check to see that the motor does not get too hot. A problem with the motor could indicate either the wrong capacitor value or a failed motor, more likely a failed motor.