Electric motors are the backbone of nearly every industrial operation. When a motor fails, quick and proper repair is critical to avoid costly downtime. At this point, business owners and managers have two main options: handle the repairs in-house or partner with a trusted electric motor service provider like NTE Service.
If you choose to manage repairs internally, our blog post, [Best Electric Motor Repair Services], walks you through the complete setup process—from understanding motor specifications to sourcing parts and performing procedures effectively.
In another article, [Basic Electrical Testing Tools], we covered essential tools and how to use them. Conducting routine inspections and ongoing maintenance is the most effective way to prevent motor failures before they happen.
However, if your facility lacks the resources or space for in-house maintenance, it’s vital to partner with a reputable electric motor service provider to ensure optimal motor performance and equipment longevity.
Your Guide to Electric Motor Service & Repair
The U.S. Department of Energy’s Office of Industrial Technologies (OIT), alongside industry experts, developed a comprehensive Service Center Evaluation Guide to help businesses identify qualified electric motor repair providers. Additionally, reputable repair shops follow the EASA AR100 standards—a set of technical specifications established by the Electrical Apparatus Service Association (EASA). Always check if a service center holds EASA accreditation.
Here’s a breakdown of what a professional motor repair process typically looks like:
1. Initial Inspection
A visual check often reveals the nature of the fault. If the windings are intact, insulation integrity should be tested. The technician rotates the shaft to check for issues like binding, warping, or worn bearings. If the motor still runs, it’s tested at full voltage without load to assess vibration and current draw. Winding resistance is then measured and all findings documented.
2. Motor Disassembly
Next, the motor is dismantled to assess internal damage. Bearings are inspected for wear, and electrical connections are cleaned and tested. A core-loss test is then performed using specialized equipment.
3. Core Preparation
The core flux test helps identify faults such as:
-
Core waviness
-
Frame or lamination cracks
-
Loose vent fingers
-
Displacement or buckled laminations
-
Wedge groove damage
-
Core bolt insulation wear
-
Signs of core movement in the stator
Repairs may include grinding, etching, or installing new insulation. If losses exceed acceptable limits, the core may need full rework or replacement before proceeding to the rewinding stage.
4. Diagnosing Winding Failures
Technicians assess winding failures by examining:
Failure modes:
-
Turn-to-turn
-
Coil-to-coil
-
Coil-to-ground
-
Open circuit
-
Phase-to-phase
Patterns:
-
Symmetrical or non-symmetrical
-
With or without grounding
-
Single-phasing
Appearance:
-
Moisture damage
-
Overheating
-
Contamination
-
Missing parts
Application factors:
-
Load type
-
Run cycles
-
Ambient temperatures
-
Voltage conditions
-
Start-up characteristics
Maintenance history also offers critical insights. Old windings are removed using heat, chemical, or mechanical methods before placing the stator in a burnout oven. Once cooled, windings are extracted and recycled.
5. Rewinding the Motor
Using precision winding machines, new coils are wound from magnet wire with enamel insulation. Coils are layered and insulated with tape for structural rigidity and electrical performance.
6. Bearing Replacement
Bearings are crucial components, manufactured to precise tolerances. Common issues include wear, incorrect installation, or insufficient lubrication—all of which can lead to premature motor failure if not addressed.
7. Reassembly & Final Testing
The motor is reassembled, tested under no load to ensure current balance and proper vibration levels, then painted and packaged for return.
Count on NTE Service for Expert Motor Support
Whether you need parts, maintenance, or full-service repairs, the NTE Service Team is here to keep your motors running reliably. Our experts bring decades of hands-on experience and industry knowledge to every repair.
