I salvaged an squirrel cage blower from an old freestanding air conditioner that I'd like to repurpose as a vent fan. The issue is, I'm not familiar with how to wire up an AC motor. I'm more use to DC where there's red and black and Bob's your uncle.

Two questions. First, given the attached picture of the wiring diagram, how do I hook it up. wiring diagram

Second, the pile of junk I pulled it from is still on the side of the road. Are there any additional pieces, starters, capacitors, that I should go back and try to salvage along with it. blower unit


Okay, I went back to the side of the road and managed to score the control board with the caps on it. My theory is that the big silver trash can looking one is for the honking compressor motor, and the smaller black one is for the blower motor. On the board, there's a big 30A relay that looks like it could handle a compressor sized motor, and the two smaller 10A relays that are labeled "FAN".

... Okay I was just about to ask if people agreed with me that the smaller black cap goes to the fan motor when I noticed that the motor plate has written on it 15uF/250V which exactly matches the rating of the small black cap. Mystery solved. caps

Now the question is what to do with the 60uF trash can cap? You know I have been troubled by squirrels on the bird feeder...

  • AC power is like if DC power put My Bloody Valentine's Loveless album on, and took a whole bunch of LSD. Tesla was an insane genius. Jun 4, 2020 at 14:18
  • Seriously though, you need to take things like that in context so you are sure you get all the necessary parts and can reverse engineer how it was hooked up. If it's at the curb anyway, just take the whole thing. Jun 4, 2020 at 14:21
  • Parts at the curb were a liberal mix of old computer parts, a couch, about 2 1/2 air conditioners and a hamster habitrail. Rooting through it I think I may have picked up legioner's disease, bed bugs, and a touch of the clap. That said, I manged to go back and find the control board. See the edit above, I think I've got it sorted.
    – A Holman
    Jun 5, 2020 at 3:12

1 Answer 1


Well, you want the capacitor, if it's not attached already/still.

Attaches to the two black wires per the diagram.

Blue to line neutral Red to line hot for high speed Yellow to line hot for low speed. So perhaps you want a switch for that.

  • Probably need to ground the case as well.
    – gbronner
    Jun 4, 2020 at 3:54
  • 1
    @gbronner Thanks for that. Green wire looks like a case ground. Will make sure to wire it up with a 3-prong plug.
    – A Holman
    Jun 5, 2020 at 2:51

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