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  1. #1
    Javid.zare.s
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    Fan transformer repair, help needed

    Hi there, hope everyone has a good time.
    I'm repairing my desk fan which seems 3 wires are torn (or more)
    I carefully took them out for welding. but the thing is I don't know which two should be welded together
    they are so close that it is impossible to find out the matching wires by eye.
    is there any other way?
    Click image for larger version. 

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  2. #2
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    Re: Fan transformer repair, help needed

    if you have a time domain reflectometer, you can figure it out based on the lengths on the various wires.
    if not, just get a new fan



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  3. #3
    Javid.zare.s
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    Re: Fan transformer repair, help needed

    Quote Originally Posted by wwfeldman View Post
    if you have a time domain reflectometer, you can figure it out based on the lengths on the various wires.
    if not, just get a new fan
    no I don't have that thing, just a multimeter
    a new fan is a waste of money for me, I should repair it no second option



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  4. #4
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    Re: Fan transformer repair, help needed

    you said you have three broken wires
    that's 6 ends
    there are two more ends where the wire in the coil is terminated

    ends 1 and 8 are the terminations of the wire in the coil
    2 and 3 are ends that should be connected, but are broken
    likewise 4 and 5 and 6 and 7

    1-----2 broken 3-----4 broken 5-----6 broken 7-----8

    number your ends 1, 2, 3, ...
    measure the resistance between each pair
    if your meter is good enough, you should be able to guesstimate which of you numbered broken ends should go together

    most of the combinations should read 0 ohm
    1 to 2 should not be zero, but 1 to 3, or 4, or 5, etc should be infinite or open (or greater than your meter can read)

    if you connect 2 to 5 and then 6 to 3 and then 4 to 7, it should not matter

    good luck


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  5. #5
    Javid.zare.s
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    Re: Fan transformer repair, help needed

    Quote Originally Posted by wwfeldman View Post
    you said you have three broken wires
    that's 6 ends
    there are two more ends where the wire in the coil is terminated

    ends 1 and 8 are the terminations of the wire in the coil
    2 and 3 are ends that should be connected, but are broken
    likewise 4 and 5 and 6 and 7

    1-----2 broken 3-----4 broken 5-----6 broken 7-----8

    number your ends 1, 2, 3, ...
    measure the resistance between each pair
    if your meter is good enough, you should be able to guesstimate whicsw of you numbered broken ends should go together

    most of the combinations should read 0 ohm
    1 to 2 should not be zero, but 1 to 3, or 4, or 5, etc should be infinite or open (or greater than your meter can read)

    if you connect 2 to 5 and then 6 to 3 and then 4 to 7, it should not matter

    good luck
    Ive connected them randomly and the motor is spinning for now!
    but its slower,for now my max speed is like the min speed.
    tried all possible configuration and all the same,
    now my question is does a faulty wiring result in a burnt down coil?Im askin cause ive run that motor for a few minutes and I kinda felt its a little too warm



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  6. #6
    Advanced Member level 1
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    Re: Fan transformer repair, help needed

    it is possible you shorted a few turns.

    say you connected 2 to 7, 4 to 5 and 3 to 6
    the 4-5-3-6 is a few turns that are not connected to the motor, but are a closed loop in the coil of the motor
    because of the 2-7 connection, the motor will spin

    because of the 4-5-3-6 short, if nothing else, some enregy will be lost to excess heating


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