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  1. #1
    Join Date
    May 2014
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    Same size motors have different size capacitors. Why?

    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

  2. #2
    Join Date
    Jun 2010
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    Re: Same size motors have different size capacitors. Why?

    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.
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