• Rewinding and Renovation of the Electric Motor

    Rewinding and Renovation of the Electric Motor
    Hello, i am MuDe, member of Yaan Electric team. i will show you, how to rewind and renovate old electric single phase electric motor.
    I bought this electric motor on garage sale. It was cheap and we know that motor burned out. I decided to buy motor and try to renovate it.
    In next steps I will show you how do disassemble
    electric motor, remove bearings, make winding diagram, rewind motor, chose right capacitor and reassemble it with new bearings.
    Rewinding is very long process. It took about two days to rewind it, replace all old parts and reassemble it.


    Step 1: How Do I Know If I Have Single Phase Motor?

    Single phase motor usually has two coils, main with bigger resistance (generating a pulsating magnetic field) and auxiliary with smaller resistance (gives motor a direction of rotation). There must be a capacitor on the motor. Its value is different for different electric engines (for smaller electric engines around 20 microF). 2 capacitor can be on motor, "run" capacitor (always connected, lower value capacitor) and "Start" capacitor (connected with centrifugal

    switch, higher value capacitor)
    Picture 1: Scheme of single phase electric motor Picture 2: Run and star capacitor
    Picture 3: Wires from stator (there should be 4 wires from stator)


    Step 2: Tools

    Rewinding and disassembling motor is very time consuming work, if you don´t have professional equipment. You will need following tools:
    • Basic tools (screwdrivers, hammers, wrenches...
    Special Material:
    • Copper wire
    • Isolate paper
    • Pulleys for bearings
    • Chisels, to cut off old winding
    • Butane torch (or other heating device)
    • Stator lacing thread
    • Spray Lubricant (WD-40 or similar)
    • Motor lacquer



    Step 3: Disassembling Motor

    Take few pictures of motor, and Remove the fan protective cover. Usually the cover is not screwed with screws on housing but it's just plugged on housing.
    Put all removed parts of motor in one box so you don't lose them.



    Step 4: Disassembling Motor

    Gently heat up motor fan and remove it. Be careful you don't break it, it should go very smooth. You can help yourself detaching it with two big screwdrivers.
    As you see on picture our motor fan is broken and we need new one. After detaching motor fan remove clamp from axis.


    Step 5: Disassembling Motor

    Mark the position of individual covers, on the side of covers (usually we put numbers 1, 2, 3 on side of covers, so we will know to assemble it).
    Unscrew the screws securing the cover (picture 2). Remove the cover of motor and put it in the box with other parts.



    Step 6: Disassembling Motor

    When I removed cover my expectations came true. One of the motors winding burned out (black colour and smell of burned lacquer).
    I find out that bearings are broken too (when you spin it, it creates loud sound).

    Step 7: Disassembling Motor

    Unscrew the screws securing the front cover (as you'we done 2 steps before). Gently remove the front cover with rotor out of main housing and put it in the box with other parts.


    Step 8: Disassembling Motor

    Unscrew the screws securing the top cover. Remove the top cover and sealing and put it in the box with other parts.
    Take few pictures of electrical installation and remove all the wires and electrical clips. Remove capacitor, if you have one on motor (our was cut off).


    Step 9: Motors Inscription Board

    Try to write down all information from inscription board. It is located on motors housing. There are some useful information on it (voltage, current, number of turns per minute, capacitor...).


    Step 10: Winding Diagram

    In next steps we are going to make winding diagram. If you have one, you cant skip titles "Winding diagram"
    What is winding diagram?
    Winding diagram is diagram which helps you rewind motor. It show how stator coils are connected with each other.


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