Background

After the coil groups are in the stator and the phase papers are in place, the back of the winding is ready to be secured. This can be done before or after the groups are hooked up. Lacing the connection end of the stator requires that all connections be made and insulation is in place and the T leads installed and the wires laid around the outside of the crown to be laced into the winding mass. A good solid tiedown is necessary to prevent noise in the end turns of the winding when the motor is in operation. When the winding is properly tied and varnished, it becomes a very solid mass with little or no end turn vibration.

Trimming phase material

Place the stator flat on a table or mount it in a stator holder. Ensure that there is plenty of work room, since the stator will have to be rotated.

Use scissors to trim the phase material at the bottom of the stator bore by nicking the paper 1 inch from the crown of the winding. Slide the scissors along the paper toward the bore.

Trim the papers 1/4 inch from the winding all the way to the stator bore. Use scissors to trim the excess phase material to within 1/8 inch of the coil ends.

Do NOT pull the phase material from under the coil side separators.

Trim the phase material at the top of the stator to the outside of the winding, leaving 1/4 inch of paper. Rotate the stator to keep the uncut papers at the top until the outside of all papers are trimmed.

Preparations for lacing

Make a lacing needle by bending an eye into a 12-inch piece of #20 magnet wire. Use locking wire twist pliers to twist the ends from the eye out to the bitter end of the wire.

The eye of the needle must be small enough to pass between the slot cell insulators.

Trim the needle to a convenient length, usually 4 to 6 inches. Ensure that the cut end is smooth.

Cut enough untreated glass lacing/tying cord to lace the stator. A length of tape about 6 yards long is all that can be worked at one time.

On large stators, it will be necessary to tie off the lacing cord. A lacing cord long enough to lace a large stator would be too long to handle without tangles.

Bend the lacing cord onto the eye of the lacing needle.

Lacing

There are two methods of lacing: the round turn and the rolling hitch. We will describe both methods and discuss uses and advantages of each.

Pass the lacing needle down between the slot papers next to the iron.

The first slot should have the needle passed down at least three times and the bitter end of the tape locked under these turns.

Continue passing the needle between all other slot cell insulators.

After every three or four turns, stop and pull the lacing tight. To make the winding neat, keep the lacing cord flat on the wire.

Rotate the stator as the lacing progresses to maintain easy access to the spaces between the slot cell insulators.

If the winding is not tight, there may be vibrations between end turns, causing early failure of the motor.

When the entire winding is laced, work out the slack in the lacing to make the winding tight.

Cut the lacing needle off the end of the lacing cord.

The half-hitch or rolling hitch knot may be used. The procedure is the same except the hitch knot must be pulled tight each time you make a turn. Also, the knots must be kept on the outside of the winding or they may interfere with the rotor after varnishing.

Bend the start and finish bitter ends together with a square knot.

Ensure that the stator bore is clear to prevent the rotor from striking the winding.