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Building/Repairing an Electric Motor

  1. Jun 2, 2010 #1
    HI all, I'm hoping to design a sort of hand held fan. I have some awesome blueprints. Unfortunately I'm still in high school in sri lanka, and we don't get much practical instruction.

    Now, I know how a motor works. To build a tiny prototype, I extracted a few small motors from some model toys. All of them seem to be almost exactly the same. They operate with 3-8V. Now I can't seem to get any of them to work. This is what they look like:

    Now i connected 3V(and also 6V at another time) to the 2 terminals, but no motion. Notice the little indent thing on the side. What is that for???

    Also, this is not fast enough for my fan. How would I go about making a powerful one. (For the second prototype, as I don't have any powerful magnets yet)
  2. jcsd
  3. Jun 2, 2010 #2


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    Staff: Mentor

    Welcome to the PF. Do you have a multimeter available? If so, check the DC resistance of the motor -- what do you get? Then set the meter on AC Volts, and spin the motor shaft -- what does it say? How about on DC Volts?

    For more power, you will need a bigger motor. Keep looking around for likely candidates...
  4. Jun 2, 2010 #3


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    Science Advisor

    Those motors should start rotating when power is applied or at least when given a small rotation. They may be faulty already and may need new brushes.

    A possible source of motors is car wrecking yards.
    A typical motor would be the one that drove the car's windscreen wipers or the fan motor for blowing air into the car.
    These are quite powerful motors and built for a very long life, so they may be working even on a car that is very old.

    These motors are better than the ones from mains voltage power tools because they will operate on 12 volts which is much safer than playing with mains voltages.

    It is possible to make simple motors yourself (Google "DIY Motor") but they will usually not be very powerful or efficient.
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