Hooking up fridge compressor to 120ac

Discussion in 'General Electronics Chat' started by RogueRose, Aug 16, 2016.

  1. RogueRose

    Thread Starter Member

    Oct 10, 2014
    189
    4
    I have a refrigerator compressor that I want to use as a vacuum pump (and possibly a compressor) but I'm not exactly sure how to wire it.


    So there is a red wire coming off the compressor (2nd pic) that goes to what I think is an over-load protector. There is a blue wire coming off the cap that is parallel to the blue wire that goes to the compressor. There is a black wire connected to the compressor to the C (common) and it runs to the cap that has an empty connector right next to it (paralleled/same connector).

    C = common
    R = Run
    S = start

    I don't know which connection needs + and one that needs - and if there is a ground connection anywhere.

    **Edit - Model - Rechi Precision model 39a131f - no HP rating available - no schmatics on the manufacturer's site, I didn't think cap size was necessary if I have it already. As far as the starting relay, there wasn't anything in the unit when this was pulled unless the relay was built into a circuit board but I don't remember anything except standard spade connections on the board.

    I the third pic, the black round thing with the red and black wires on it, is that the relay you speak of?




    This is a pic of the starting cap. There is an empty terminal behind the connector on the top right
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    Last edited: Aug 16, 2016
  2. #12

    Expert

    Nov 30, 2010
    16,320
    6,818
    Hmmm...no brand name, no model number, no part number, no capacitor size, no horsepower rating, no schematic, no hint whether it needs a starting relay..sure. Let me get my crystal ball and I'll hook you right up.

    After you get it running, you can use it for a vacuum pump until the motor windings arc. That should happen somewhere between 15 and 30 inches of vacuum on a standard refrigerant manifold set.
     
    Last edited: Aug 16, 2016
  3. RogueRose

    Thread Starter Member

    Oct 10, 2014
    189
    4
    Original post updated...


    I didn't post all the info because from what I have read and watched on videos, the wiring seemed standard on all compressors.

    As far as you saying the arcing being a problem, have you used a compressor like this before for either of these applications?
     
  4. tcmtech

    Well-Known Member

    Nov 4, 2013
    2,039
    1,667
    I've been using old compressors like that all my life as vacuum pumps and have never had one burn out.

    At worst, I've killed a few due to sucking in stuff that shouldn't have been ran through the mechanical ends but none have ever died from high vacuum related motor failures.
     
    RogueRose likes this.
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