Blog › Motor Winding  |  By Parth Enterprises, Faridabad

Motor Winding Process Step by Step – Beginner's Guide

Motor winding — the process of winding copper wire coils into a motor stator or rotor — is one of the most important skills in the electrical repair industry. Whether you are rewinding a burned-out ceiling fan motor or manufacturing new submersible pump motors, the process follows the same fundamental steps. This guide covers the complete motor winding process for beginners.

Materials You Need

Before starting any motor winding job, gather these materials:

• Copper wire: Enamelled copper wire in the gauge matching the original winding
• Polyester winding thread: ROHS compliant polyester thread — 300m rolls for hand winding or 1500m cones for machines
• Insulation paper: Nomex, polyester film, or slot insulation paper
• Insulation tape: Pink tape or glass tape for layer and coil insulation
• Insulation varnish: For sealing and protecting the completed winding
• Sleeve material: Heat shrink or PVC sleeves for lead wire insulation

Step 1: Record Original Winding Data

This is the most critical step in rewinding. Before removing the old winding, record:

• Number of coils per phase
• Number of turns per coil
• Copper wire gauge (measure with a micrometer)
• Coil span (how many slots each coil spans)
• Connection pattern (star or delta, series or parallel)
• Lead wire positions and colours

Step 2: Strip the Old Winding

After recording winding data:

1. Cut the coil connections and lead wires
2. Heat the stator in an oven (180-200°C for 2-3 hours) to soften the varnish
3. Pull out the old coils carefully — avoid damaging the stator laminations
4. Clean all slots thoroughly — remove all old insulation, varnish, and wire fragments
5. Inspect the stator core for damage, hot spots, or lamination shorts

Step 3: Insert Slot Insulation

Place slot insulation (Nomex or polyester film) in each stator slot before winding. The insulation must extend 2-3mm above the slot opening on both sides to provide adequate clearance between the copper wire and the stator core.

Step 4: Wind the Coils

This is the main winding operation:

1. Set up the winding jig: Adjust the jig to the correct coil span
2. Count turns carefully: Use a turn counter or count manually. The turn count must match the original data exactly
3. Maintain tension: Keep consistent tension on the copper wire — too loose causes vibration, too tight damages insulation
4. Place coils in slots: Insert each coil into its designated slots, following the recorded coil span and connection pattern
5. Bind with polyester thread: Use polyester winding thread to bind each coil securely in its slot. The thread prevents the coil from moving during motor operation

Step 5: Insulate Between Layers

After placing each coil group, apply insulation between the layer and the next group of coils. Use Trinity pink tape for standard applications or glass tape for high-temperature motors.

Step 6: Make Connections

Connect the coils according to the recorded connection pattern:

• Solder or crimp connections securely
• Insulate each connection with sleeve material and tape
• Route lead wires to the terminal connection point
• Verify connections with a multimeter before proceeding

Step 7: Test Before Varnishing

Before applying varnish (which makes changes difficult), test the winding:

• Resistance test: Measure resistance of each phase — they should be equal (within 2%)
• Insulation resistance test: Use a megger to check insulation between windings and between windings and the stator core
• Surge test: If available, use a surge tester to check for turn-to-turn shorts

Step 8: Varnish and Cure

1. Dip or drip insulation varnish into the completed winding
2. Ensure varnish penetrates all layers and fills air gaps
3. Bake the stator in an oven at the varnish manufacturer's specified temperature (typically 120-150°C for 2-4 hours)
4. Allow to cool completely before assembly

Step 9: Final Assembly and Testing

1. Reassemble the motor (bearings, rotor, end shields)
2. Run the motor unloaded to check for vibration, noise, and bearing issues
3. Check current draw — it should match the nameplate rating
4. Load test if possible to verify performance

Frequently Asked Questions

What materials are needed for motor winding?

Essential materials: enamelled copper wire (gauge matching the original), polyester winding thread (300m rolls for manual, 1500m cones for automatic), insulation paper/Nomex, insulation tape (pink tape or glass tape), insulation varnish, and appropriate tools.

How long does it take to rewind a motor?

A ceiling fan motor rewind takes 1-2 hours for an experienced rewinder. A water pump motor (1-3 HP) takes 2-4 hours. Industrial motors can take 4-8 hours depending on size.

What is the most common mistake in motor winding?

The most common mistake is using incorrect wire gauge or not recording original winding data before stripping. Always document everything before removing the old winding.