How to repair a generator

Written by james stevens
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How to repair a generator
Replace the brushes and bearings to repair your generator (Hemera Technologies/ Images)

Electric generators usually operate maintenance free, but if they do go wrong there are only two main parts that can be repaired by most users, the bearings and the brushes. The other internal parts that may go wrong are the wire windings on the armature and generator casing. If this happens they need to be rewound professionally.

Skill level:

Things you need

  • Replacement bearings
  • Replacement brushes
  • Screwdriver
  • Clean cloth
  • Pliers

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  1. 1

    If your generator is making a loud, metal-on-metal noise, replace the bearings. While you are replacing the bearings it's also a good idea to replace the brushes, even if they don't appear worn. They are inexpensive to replace and are part that wears out the quickest.

  2. 2

    To replace the bearings, remove the screws on the generator casing using a screwdriver. Carefully lift off the top half of the generator casing. You can't completely remove the casing as the top and bottom are wired together, but you can position it suitably to get to the armature.

  3. 3

    Lift the armature from the bottom casing of the generator using your hands. The armature runs centrally from the front to the back of the generator and can be completely removed. As you remove it the old brushes will fall out of the brush holders.

  4. 4

    Pry out the bearings using a flathead screwdriver. Carefully insert the screwdriver between the base of the bearing and the generator case and twist the screwdriver to release the bearing. There are bearings at the front and rear where the armature sits. Separate bearings are in the top half and bottom half of the casing so you need to remove four in total.

  5. 5

    Wipe the area where the bearings were positioned using a clean cloth. Place the new bearings in the place you just removed the old ones. Press then into position using your fingers. Don't use anything metal to push them in place as you may damage them.

  6. 6

    Locate the clips that hold the brushes in place. You find one either side of the casing diagonally opposite each other either at the front or back of the generator. Use a pair of pliers to pull out the clips. Remove the springs from the brush holders', using the pliers, then check that the brush holders are empty.

  7. 7

    Replace the armature using your hands by placing it onto the bearings. Replace the top casing onto the bottom casing using your hands. Replace the screws and tighten them using a screwdriver.

  8. 8

    Insert a replacement brush into one of the brush holders. Push the spring into the holder. Use pliers to keep the spring in place while you insert the retaining clip into the holder. You can usually do this using your fingers. Repeat the process for the other brush.

Tips and warnings

  • Ensure you purchase exactly the same type of bearings and brushes. Make a note of the generator type and take the old bearings and brushes to the store for reference.

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