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Proper fabrication of coils for winding replacement in a motor can ensure greater ease of insertion of coils into a stator. The simple matter of proper location of crossovers can greatly facilitate insertion of coils. Other procedures, such as taping coil knuckles, ensure a solid, quiet winding.

Winding machine and coil setup

Coils are wound on coil winding machines. These machines can be used to wind either diamond or round-nose coils. This lesson will discuss the Potter Rayfield winding machine. Each of the machine's adjustable segments has two index marks corresponding to a set of finger mounting holes. Use the index marks in line with the finger mounting holes being used.

Potter Rayfield Winding Machine

Open and lock the winding head.

Set in the length of the coil.

The coil side length must allow for a 3/8-inch cuff on each side of the iron. The coil side length setting will equal the iron width plus 3/4 inch.

Set in the length of the coil sides.

The coil width equals the span measured in inches.

Set in the width of the coil.

Do NOT operate the winding machine while wearing a necktie, long sleeves, or other loose clothing.

Ensure that the guide bars are in place.

Horizontal bars for reels with no braking system will allow wire to spill, causing a wire loss and a footing hazard.

Position reels with the required size wire on the dereeler. The number of reels equals the wires in hand. Discard any damaged reels to prevent nicking the wire.

The Potter Rayfield machine uses a clamping device. Other types use a loop over a projection.

Lead wire from the dereeler through the tensioning device to the winding head. Set the tensioning device lightly on the wire.

Check for proper speed setting and direction of rotation of the winding head.

Set the turn counter on zero. Set in the number of turns per coil on automatic machines.

Wind and prepare coils to be installed in a stator prepared for rewinding.

Wind a sample coil. Unlock the winding head and remove the sample coil.

Lay the sample coil in the stator in which the coils will be installed. Check the fit of end room and span. Make necessary adjustments on the winding head to ensure proper size coils.

Open and lock the winding head and set the machine to wind a group. A group consists of several coils. Your fingers must contact the wire while winding to detect nicks and breaks. Discard all groups with damaged wire.

The crossover is the point of change over from one coil to another. The crossover must be made at the same point the first coil entered the fingers and must occur at the same point on all coils.

Use a system to note crossover with the proper turns in each coil.

Click on image to enlarge.

Winding Head and Wire Guides

When the group is wound, tie the sides of each coil with cotton twine (see figure at right). Use a knot that will pull out easily. Do not tie in the crossovers

Cut the wire and remove the group from the winding head. Carefully lay the group on a table or hang it on a stand.

Tape the knuckles of each coil with one layer of glass thermosetting tape. Do NOT tape the crossovers or lead.

Wind the number of groups required for the motor being rewound.

Hang the groups on a rack until they are ready to be inserted.

Twine and Tape Applied to Coils

Click on image to enlarge.

Completed Wound Round-Nose Groups on Rack