Background

A motor winding that requires replacement must be properly identified and all the pertinent information recorded before any connections are broken and the winding destroyed. If this is not done and the winding is changed or modified inadvertently, the repaired motor will not operate properly.

The master drawing of the stator to be rewound is the primary source of rewind data. If the information in the master drawing does not match the existing winding, proper winding data can be verified via NAVSEA 56Z32.

If the master drawing is not available, you can get information from the old winding. Always compare old winding data to that listed in the manufacturer's technical manual, if available. In any case, any discrepancies between the old winding data and that listed in the available technical documentation must be resolved before you proceed.

The winding diagrams prepared in the lesson on motor rewind will help you visualize the motor winding and makes obtaining the required data easier.

  Much of the rewind information required would actually be obtained after stator burnout. Procedures for obtaining this information will be discussed in this lesson.

Obtaining and entering rewind information in the motor repair identifcation sheet

  The figure at right shows a typical motor repair identification sheet and will be referred to and used during this lesson. In cases of two-speed two-winding motors, consequent pole motors, or dual voltage motors, information can be entered either for both speeds or voltage on the same sheet or use two separate sheets.

Nameplate data. Observe and compare the motor nameplate and available technical documentation. Resolve any discrepancies and enter the required information in the spaces provided.

Coil shape. Examine coil ends to determine if they are round-nosed or diamond-shaped. Enter the information in the space provided.

Number of poles. Obtain the motor's operating speed (revolutions per minute or r/m) from the motor nameplate. Locate the motor speed and the corresponding number of poles on the motor speed table. Enter the information on the motor repair identification sheet in the space provided.

Number of slots. Carefully mark any slot with a scribe, chalk, etc., as slot number 1. Starting with slot 1, physically count the number of slots. Enter the information in the space provided on the motor repair identification sheet.

Basket windings usually have one coil side per slot and half the number of coils as slots. Distributed windings will have two coil sides per slot and the same number of coils as slots. Some two-speed two-winding motors will use a basket winding for low speed and a distributed winding for high speed.

Number of coils and coil sides per slot. Examine the stator to determine if the winding is a basket or distributed winding. Enter the information in the space provided on the motor repair identification sheet.

Click on image to enlarge.

Typical Motor Repair Identification Sheet