Rewinding Electro Motor

What it is
Rewinding restores an electric motor’s performance by replacing aged or burnt windings and renewing the insulation system. The goal is to recover efficiency, torque, and reliability while extending motor life.

When it’s needed

• Burnt/shorted windings, frequent tripping, abnormal current

• Overheating, low insulation resistance, moisture/contamination

• Bearing failure causing stator-rotor rub, or visible coil damage

• Energy recovery after long hours or harsh duty cycles

Scope of work (typical process)

1. Incoming inspection & diagnostics – nameplate verification, visual check, vibration & temperature notes, baseline current.

2. Electrical tests (pre-repair) – Insulation Resistance (IR), Polarization Index (PI), surge/hi-pot (as applicable), continuity.

3. Disassembly & stripping – remove end shields, rotor, old coils, clean stator/rotor; assess core/lamination.

4. Core test & preparation – core loss test (as needed), slot cleaning, install new slot liners & wedges.

5. Rewinding – wind new coils with quality copper wire; select wire gauge/turns per original spec or re-design if requested.

6. Insulation system – Class F/H materials; coil lacing, tying, and phase insulation to spec.

7. Impregnation & curing – varnish dip or VPI (Vacuum Pressure Impregnation) for superior dielectric strength, then baked to cure.

8. Reassembly – replace bearings, seals, and hardware; align shaft, check endplay and air gap.

9. Balancing & mechanical checks – dynamic balancing to ISO tolerance (where needed), coupling inspection.

10. Final electrical tests – IR/PI, surge/hi-pot, no-load run, current balance, temperature rise observation.

11. Painting & finishing – corrosion-resistant finish, tagging, and documentation.

Deliverables

• Test report (before/after), photos, list of replaced parts

• Run test data & balancing sheet (if applicable)

• Limited warranty per scope and operating conditions

Optional upgrades

• Insulation Class H, tropicalization/moisture protection

• Bearing upgrade (sealed/ceramic as application requires)

• Shaft repair, sleeve, or soft foot correction

• On-site removal/installation & alignment service

Benefits for your plant

• Restored efficiency & reliability at a lower cost than new motors

• Reduced unplanned downtime with documented QA

• Longer service life with correct insulation and impregnation system

Standards & Best Practice: Work is performed following applicable industry guidelines (e.g., IEC/NEMA, EASA AR100 practices). Final scope can be tailored to your site and duty cycle.