Same size motors have different size capacitors. Why?

[RCBARBER]

Got an electric motor 550w (0.7hp) with a 14ųF start capacitor. Got a 3/4hp (0.75hp) comp with a 64ųF start capacitor. Im assuming it to do with the way they are wound. Anyone have a deeper explination to this? You would assume similar motors would have similar sized capacitors

[chilliwilly]

It would appear that one of them could have the wrong size capaitor, the effects of it will be seen later if the compressor has a high cycling duty (start stops). A larger capacitor can be used as a start within a percentage margin but not usually 8 x larger.


The speed and torque can also make a difference but multi speed motors are usually reserved for 3 phase rather than single phase as they don't need an artificial starter such as a capacitor.

Are you sure its not a pf or run capacitor for a permanent split phase motor? Starts caps are usually have a black case and pf an alli case, unless of course its a multi type which are usually in an oval alli case containing 2 caps.