# Electric Motor Repair in St. Louis, MO

> Electric motor repair, rewinding, and rebuilds in St. Louis, MO. Custom modifications for motors nobody else can fix. Family-owned since 1944. (314) 531-1888.

Canonical: https://www.cemsi.net/repairs-and-modifications/

![Technician rewinding an electric motor stator with copper wire](/wp-content/uploads/hf_20260610_205848_60a3d939-2158-4dd4-b99d-a9c02ff5b8e4_min.webp)

Repairs & Modifications

# The Shop That Fixes What Others Won't Touch

Out of options on an unusual motor? Bring it to the counter. Three generations of repair knowledge plus a network of industry connections means we devise solutions, not apologies.

[Find My Motor](/contact/)[Call (314) 531-1888](tel:314-531-1888)

Custom Solutions

## Repairs, Rewinds, and Motors Rearranged to Fit

If you have an unusual motor you can't find parts for, you haven't exhausted your options until you've been here. Our staff repairs, rebuilds, and modifies motors, from fractional horsepower units to large electric motor repair for industrial equipment. That includes physically rearranging components so a motor fits into a tight spot the original never had to.

Whatever the custom project, the combination matters: three generations of hands-on experience and supplier connections throughout the industry. Call [(314) 531-1888](tel:314-531-1888) or [contact us](/contact/) to start.

![Electric motor repair and rebuild work at Commercial Electric Motor Service in St. Louis, MO](/wp-content/uploads/ThinkstockPhotos-520566511-1920w.webp)

Our Repair Protocol

## Eight Steps Between a Dead Motor and a Like-New One

A motor rebuild here isn't a cleaning and a prayer. Every repair follows the full protocol:

- Complete disassembly and chemical cleaning to remove carbon buildup and debris
- Detailed inspection of stator windings, rotors, and shafts for structural integrity
- Bearing replacement with sealed, high-temperature grades rated for continuous operation
- Precision motor rewinding using Class H or F insulation to withstand thermal stress
- Vacuum pressure impregnation (VPI) with epoxy varnish against moisture and contaminants
- Dynamic rotor balancing to eliminate vibration and ensure quiet performance
- Full load testing under simulated operating conditions to verify amperage draw and efficiency
- Final quality assurance check of alignment and mounting specs before delivery

This is why a rebuild from this shop offers longevity comparable to a new unit, and why HVAC techs across the region send us the motors they can't save.

From the Blog

## Advice from the Counter

[Repair Costs

### Why Timely AC Motor Repair Saves Money

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### AC Fan Motor Not Spinning? 5 Warning Signs

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### AC Fan Motor Replacement: Cost & Benefits

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★★★★★4.8from **132**  Google reviews

★★★★★

> "With only a few pictures, Doug was able to match a vintage motor over 50 years old. Had a new one in stock, and the staff even configured the wiring for a minimal fee."

Grant G. Vintage motor match

★★★★★

> "You will not find an electric motor shop more knowledgeable and better stocked than Commercial. 20-year customer and their knowledge always impresses me."

James H. 20-year customer

★★★★★

> "Great service and a go-to place for any of our motor needs. They get me what I need the first time! Definitely recommend this place to anyone in the business."

Mike F. Trade professional

Questions

## Frequently Asked Questions

Is electric motor repair cheaper than replacement?

For larger, specialty, or hard-to-replace motors, repair usually wins. For small standard motors, a new unit is often cheaper than shop time. We'll quote both honestly. We sell new motors too, so we have no incentive to push the wrong answer.

What is motor rewinding and when is it needed?

Rewinding replaces burned or shorted copper windings in the stator. It's the fix when insulation fails from heat or age but the mechanical core is sound. We rewind with Class H or F insulation, better than many motors had from the factory.

Can you modify a motor to fit where the original won't?

Yes. Rearranging motor components to fit tight spots is a specialty. Bring the motor and the constraints and we'll engineer around them.

Do you repair vintage and obsolete motors?

Constantly. A customer recently brought photos of a motor over 50 years old and walked out with a solution. Old, odd, and obsolete is the work we're known for.

## Got a Motor Nobody Can Fix?

Bring it to 3121 Washington Blvd. or send photos. Our staff will devise a solution.

[Call (314) 531-1888 Now](tel:314-531-1888)