Electric Motor Shop Logo

(800) 970-5859

Electric Motor Shop Logo

(800) 970-5859

Electric Motor Repair Process

Expert diagnostics, precision rewinding, and full testing—done right the first time.

1 – Receiving & Testing

Motor Arrives for Repair

  • Each motor is photographed upon arrival to document its condition and verify all attached components (couplings, fan covers, connection boxes, etc.).
  • Nameplate data is recorded to ensure accurate identification.
  • A job card is created to track the motor through every phase of the repair process.
Electric Motor Shop technician unloading industrial motor from delivery truck with forklift for repair documentation and inspection.
Large electric motor on pallet at Electric Motor Shop, photographed on arrival to document condition and components before repair.

Initial Electrical Testing

  • Static electrical tests are performed on the windings to assess insulation condition. These include a resistance test, megger test, hipot test, and surge test.
  • If results are within acceptable limits, the motor is energized and test-run to evaluate mechanical performance.
Electric Motor Shop technician performing initial static electrical testing on large industrial motor to assess insulation and winding condition.
Close-up of Reliance motor nameplate showing electrical specifications for documentation during repair process at Electric Motor Shop.

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2 – Disassembly & Inspection

Motor Disassembly

  • The shaft is checked for trueness.
  • The motor is disassembled, and the rotor and bearings are removed for further inspection.
Technician using dial indicator to check motor shaft trueness before disassembly.
Electric Motor Shop technician preparing to disassemble electric motor and inspect internal components.
Technician removing motor bearing during disassembly to inspect shaft and internal wear.
Rotor being extracted from motor housing with lifting tool during detailed disassembly process.

Precision Inspection

  • All machine fits are inspected and measured against industry standards.
  • Visual inspections identify damage such as cracked housings or broken fans.
Electric Motor Shop technician recording bearing condition and inspection results during motor repair process.
Close-up of worn motor bearing and shaft damage discovered during visual inspection.
Detailed view of micrometer used to inspect shaft dimensions on electric motor rotor.
Technician measuring rotor shaft diameter with micrometer to ensure precise machine fit.

Rotor Evaluation

  • Rotor bars are tested to verify electrical and mechanical integrity.
  • This ensures optimal motor efficiency and performance upon reassembly.
Rotor staged for testing at Electric Motor Shop to verify bar integrity and prepare for reassembly.
Technician inspecting rotor bars for electrical and mechanical integrity during motor evaluation process.

Stator Diagnosis – Motor Winding Failure

  • The stator windings are visually inspected for signs of electrical failure.
  • If shorted or damaged, the stator is flagged for a complete rewind.
Interior view of electric motor stator showing copper windings during visual inspection for electrical failure.
Detailed image of stator winding insulation with visible wear, inspected for potential short circuits or damage.
Severely contaminated and burnt stator winding with signs of insulation breakdown and motor failure.

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3 – Core Processing & Burnout

Core Loss Testing

  • A computerized LEXSECO test is conducted to check for iron damage before burning.
  • This critical step ensures the stator core is still suitable for reuse.
Electric Motor Shop technician performing computerized LEXSECO core loss test to detect iron damage before stator core reuse.

Burnout Preparation

  • The stator is prepped for burnout to safely remove old windings.
  • This step sets the stage for a clean and accurate rewind process.
Technician at Electric Motor Shop preparing stator for burnout process to remove old windings safely.
Stator with damaged windings partially extracted, prepped for complete removal and rewind.

Burnout Process

  • The stator is placed in one of our two state-of-the-art temperature and flame controlled burnout ovens.
  • This removes the insulation without damaging the core laminations.
Electric motor stator positioned inside temperature-controlled burnout oven to remove insulation safely.
Technician at Electric Motor Shop loading stator into flame-controlled burnout oven for insulation removal without damaging core.

Coil Removal & Documentation

  • Burnt windings are carefully extracted from the stator slots.
  • Turn count, pitch, and wire size are recorded to ensure the new windings match original design specs.
Technician manually extracting burnt stator windings with hand tools to prepare for documentation and rewind.
Stator core with all coils removed, ready for cleaning and rewinding after winding specs are documented.

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4 – Rewind & Insulation

Rewind Prep

  • The stator iron stack is inspected and repaired if needed.
  • The iron core is coated with an enamel insulating finish to ensure dielectric strength.
  • NOMEX insulation papers are carefully installed to prepare for coil insertion.
Technician applying red insulating enamel coating to motor stator core to restore dielectric strength before rewind.
Fully enamel-coated stator core with prepared slots, ready for coil insertion during motor rewind process.
Electric Motor Shop technician placing NOMEX insulation paper into stator slots in preparation for new winding coils.

Coil Manufacturing

  • New coils are precision-wound using a SAMATIC coil machine.
  • Coils are labeled and staged for organized installation.
Close-up of new copper motor coils being precision-wound on SOMATIC coil machine at Electric Motor Shop.
Technician organizing freshly wound and labeled motor coils for installation during stator rewind process.

Coil Insertion

  • New coils are carefully inserted into stator slots by hand to avoid insulation damage.
  • Phase insulation is added to maintain electrical separation and safety.
Newly wound motor coils hand-inserted into stator slots with phase insulation for electrical separation and protection.

Coil Termination & QA Testing

  • Coil ends are connected based on the motor’s original winding design.
  • End turns are tightly secured and the stator is electrically tested to verify proper installation.
Technician connecting coil leads according to original winding design during motor rewind termination process.
Coil end turns securely bundled with phase insulation in place, prepared for final electrical testing.

VPI Impregnation

  • The stator is vacuum pressure impregnated with resin to eliminate air gaps and seal the windings.
  • This process increases durability, heat dissipation, and resistance to contamination.
An electric motor stator being lowered into a large vacuum pressure impregnation (VPI) tank filled with resin. Chains and hooks are attached for safe handling.
Close-up view of a stator with newly wound coils fully wrapped in white insulation, ready for resin impregnation. The interior is clean and precisely organized.

Final Bake

  • The stator is baked in a controlled oven to fully cure the resin and lock in the windings.
A stator sits inside an industrial baking oven, coated with cured resin that gives the windings a glossy finish. The resin has begun to pool at the base, indicating the curing process is underway.

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5 – Reassembly & Final Testing

Rotor Balancing

  • Rotating elements such as rotors, fans, and pulleys are dynamically balanced.
  • All components meet or exceed precision industry standards for vibration control.
A technician operates a dynamic balancing machine as a red-painted rotor spins between two green support stands. The control cabinet displays vibration data to ensure the rotor meets industry balance standards.

Paint & Rotor Installation

  • All necessary components are painted for protection and appearance.
  • The rotor is carefully aligned and installed into the stator.
Technician using a hoist to carefully align and install the rotor into the stator housing on a workbench.
Rotor fully inserted into the stator with neatly wound and cured coils visible around it, showing precise installation and assembly.
Close-up of two freshly painted red motor end bells placed side by side on the shop floor.

Final Reassembly

  • Bearings are installed.
  • End housings and other components are reassembled to factory specs.
Technician installing a bearing on the motor shaft during final reassembly of the electric motor.
Technician guiding the end bell into position as part of the final motor assembly process.
Technician applying touch-up spray paint to the motor’s exterior housing during the final reassembly phase.
Technician applying touch-up spray paint to the motor’s exterior housing during the final reassembly phase.

Final Electrical & Mechanical Testing

  • Motor windings undergo surge and hi-pot testing to confirm electrical soundness.
  • The motor is then run at full voltage and checked for vibration and overall performance.
  • Test results are logged and added to the final report.
Final electrical testing of industrial electric motor using surge tester and hi-pot equipment in a motor repair facility.

Ready for Delivery or Pickup

  • The motor is cleaned, labeled, and prepared for return to the customer.
  • All documentation and test reports are finalized and delivered with the unit.
Fully repaired industrial electric motor cleaned, labeled, and prepared for customer pickup with final inspection tag attached.

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