Electric Motor Repair

Electric Motor

Rewinding Electric Motors

Electric motors are relatively simple mechanical devices, but rewinding the coils on a DC motor is a precise task that should only be undertaken by those who with experience in mechanical or electrical repair. A mistake or poorly-performed rewind job will result in a motor that doesn’t work. At that point, your only options are to buy a new motor or to take it to a professional shop for repair. Given the variety of motors and types of windings, this can only be a general article on rewinding. If you don’t understand the terminology, you shouldn’t be rewinding a motor; once you start removing the original coils, there’s no going back.

Steps

1. Clean the motor from the surface to make sure it’s free of dirt and other debris.
2. Check the motor nameplate and ensure that all important details are clear.
3. Check the motor housing to see the armature, stator, and the windings.
4. List down all important details and document the present configuration by taking notes or photographs. You may even wish to videotape your deconstruction so that you can precisely recreate the original winding pattern and connections.
5. Take the wire from the tabs on the brush pads. Bend the tabs gently (and as little as possible) and completely remove the wire from the tabs before cutting the coils of the wind.
6. Cut the coils in the wind free from the armature and/or stator. The easiest place to cut is at the tops of the coils at the top of the armature and/or stator posts. Count the number of winds in each coil so that you can rebuild the motor to its original configuration.
7. Check the insulation that lines the actual steel laminate areas of the stator before you rewind an electric motor. If it’s in good shape, you can put it back in place before beginning your rewind. You can replace burned or damaged insulation with similar material or insulating tape.
8. Start rewinding the armature and/or stator using the same gauge and type of magnet wire that was on the original motor. If you’re more experienced, you may wish to upgrade your wire’s quality, substituting a nylon-and-polyurethane-coated wire for the original enamel-coated wire, for instance.
9. Follow the the exact winding pattern and number of coils around each winding.Take great care to make each coil tight and precise for the best performance.
10. Reconnect the end of the last winding and the loose wire you left in the first winding to the tab where you began.
11. Make sure that none of the wires connecting to the tabs are touching.

Note:

• When beginning your first winding, leave the end of the first winding free but long enough to reach the first tab. The last winding will attach to the same point.
• Crimp all the other windings down as you work to hold the wire in place. You do the winding with one long wire, so don’t cut anything as you go.
• Before you crimp the wire down behind the tabs, use a sharp knife or sandpaper to remove the insulation from the wire at the point where it makes contact with the tab. Make sure you only remove as much insulation as is necessary to create good contact.

Download eBook

Click to download

Click to download