capacitors & motor Question

Discussion in 'General Electronics Chat' started by Cliff987, Jun 4, 2013.

  1. Cliff987

    Thread Starter New Member

    Oct 2, 2012
    I have a 120 vac motor. It's a fan motor combo from an April Air dehumidifier. It worked fine, then I removed it from the appliance in which it had lived because the compressor locked up.

    It has three wires, Blue Yellow and Green with a pale Yellow stripe this last one is ground.

    It's got two capacitors. One is a big cannister 35 micro farad 370 Volt

    And a Cera mite 305C20 it's little.
    It is this exact one$%28KGrHqF,!psFBdl%28G!,rBQnSUWEWIg~~60_57.JPG
    The ebay item has nothing to do with me it's just a good picture of the capacitor

    Anyway I can get the motor to start up - without the cera mite - but after running for a couple of seconds it gives a lurch like there is a brake thrown and then hums making an awful noise and not turning (See video linked below)

    I don't know how to put the Cera Mite in the line AND I think that there should be some kind of switch to remove it from the line after the motor is up and running. Originally this motor was connected to a logic circuit which I do not now have.

    Any ideas?

    Here's the video of the thing doing what I described.

    I wondered if the larger cap was what ran the compressor. This would make sense since I didn't find another one but the large cap is the only way to get the motor up to speed. When I try the little Cera Mite I can only get the motor to turn over a little bit.
    Maybe it's cooked?
  2. #12


    Nov 30, 2010
    You're having a mechanical problem. Take the motor apart and see if the end holder for the armature has been worn off center so the armature laminations hit the stator laminations. Some motors are so cheap that they don't even have a bushing insert. The end plate is simply bored out to make a socket for the armature. The end plate is aluminum and the bored hole wears out and walks off center.
  3. Cliff987

    Thread Starter New Member

    Oct 2, 2012
    Nope, the motor is in fine mechanical shape. It wasn't a particularly inexpensive motor either. It's an EBMPAPST (an OEM motor manufacturer This one cost me about $250 from Newark electronics, the dehumidifier company wanted $700 to sell me the replacement. I thought that was a little steep so I sourced it myself. Now however the dehumidifier is Kaput.

    As a cautionary note: Never - - ever buy a Research Products Inc product they are very badly made.
    I got their two larger dehumidifiers and both failed. On one the blower failed first and then the compressor locked up.
    On the other A capacitor blew that was made in mexico with no MFD or Volt markings to guide me replacing it. Then a solder joint failed and let all the refrigerant out into the house and killed the compressor.
    April Air (Research Products) does not warranty their equipment.
  4. tubeguy

    Well-Known Member

    Nov 3, 2012
    Can you post specs - specific model number of the motor ?
    Last edited: Jun 5, 2013