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-   -   Wiring 3/4 horse fan motor (https://www.askmehelpdesk.com/showthread.php?t=218406)

  • May 21, 2008, 03:26 PM
    jerryyoder
    Wiring 3/4 horse fan motor
    Hello!

    I am replacing a 3/4 hp GE motor for the fan (blower) with a Marathon motor with the same specs for our 14 year Carrier heat/air unit.

    The Marathon has one extra wire that I don't know what to do with.

    The wires that are obvious are the black, blue & red. The green ground wire. Then the brown and brown/white wires go to the capacitor.

    The Marathon has a white wire (labeled common) that the GE motor didn't have... what do I do with this?

    Also... how do I know which terminal on the capacitor to connect the brown and brown/white wires to?

    Thanks so much. I'm trying to keep this old unit limping along before I need to replace it.
    :o
  • May 21, 2008, 03:37 PM
    hvac1000
    Is it a 120/240 volt motor otherwise known and a dual voltage motor. If it is the white is used on 120 volt power. If your unit is a 240 volt setup just tape off the white wire.
  • May 21, 2008, 03:40 PM
    KISS
    That capacitor is not polarity sensitive.
  • May 21, 2008, 03:54 PM
    hvac1000
    That capacitor is not polarity sensitive

    Dang I forgot that part. Thanks KeepITSimpleStupid for catching that one. Somedays I think I am in the clouds. Tuff day at the University. LOL
  • May 21, 2008, 04:20 PM
    jerryyoder
    2 Attachment(s)
    Thanks guys... here's a bad picture of the original to give you an idea.

    The new motor has all the same specs, but has the added white wire.

    The new motor says 115 Volts.

    What is a "common" wire? Does it carry voltage? It's not a common ground right?

    Sorry for all the terribly novice questions.
  • May 21, 2008, 04:35 PM
    hvac1000
    You need to wire the motor up as a 120 volt motor not a 240 volt motor. The common/neutral leg is the companion leg to the hot leg on 120 volt hook ups. Black, blue & red. I believe the black wire should be the hot leg to get the 120 volts. BUT wire it according to the diagram on the new motor!!
  • May 21, 2008, 04:37 PM
    KISS
    Is this motor 3 speed?

    Did you buy a new cap with it?

    The stuff in the picture on the right is missing. This is gong in the inside unit, right?

    My GUESS is white is neutral and black, red and blue are the 3 fan speeds.
  • May 21, 2008, 04:39 PM
    jerryyoder
    Yes, this motor is a 3 speed and I bought a new cap... The cap just has 2 poles.

    Considering the 3 speeds... what would I connect the white wire to?
  • May 21, 2008, 04:45 PM
    KISS
    The white wire connects to the grounded conductor. e.g. Neutral of the furnace, white.

    You pick the speeds and connect the hot to the appropriate speed.

    Assume motor is no in unit.
    Attach cap wires to cap.
    Connect white to wide blade of 120 V plug
    Pick a color (black, blue or Red) and attach to the other side of the plug
    Tape the remaining colors.
    Plug in. Motor should run.
  • May 21, 2008, 04:57 PM
    jerryyoder
    Thanks K.I.S.S.
    I included a picture a little earlier... this is an outside main heating/air unit for my house..

    Sorry for the confusion.
  • May 22, 2008, 07:40 PM
    T-Top
    I would remove the insulation from around the blower housing before its sucked up into the blower wheel and takes out the new motor.

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