When an electric motor starts to malfunction, overheat, or fails completely, this does not necessarily mean it has to be replaced immediately. In many cases, overhaul or repair—especially rewinding—is a cost-effective and sustainable alternative. In this blog, we share our insights, hands-on experience, and tips on repairing and rewinding electric motors.

When Is Repair or Overhaul of an Electric Motor Worthwhile?

Electric motors are often subjected to heavy loads in demanding environments. Wear on bearings, insulation damage, moisture, dust, or thermal stress can eventually lead to power loss or complete failure.

Repair or overhaul is often worthwhile when:

• the motor is still mechanically sound (e.g. housing, rotor, shaft)

• replacement costs are high or delivery times for a new motor are long

• custom components are not readily available

• sustainability and circularity are part of the maintenance strategy

Instead of investing in a new motor, the existing motor is restored and optimized for reuse.

Rewinding an Electric Motor: How Does It Work?

Rewinding an electric motor involves removing and replacing the copper windings in the stator. This is precision work and typically includes:

• Disassembling and cleaning the motor

• Removing damaged or burnt windings

• Winding new coils exactly according to the original specifications (or improved ones)

• Impregnating the windings with resin for insulation and protection

• Reassembling and testing the restored motor (e.g. high-voltage test, resistance, vibration)

A properly rewound motor delivers optimal performance again and complies with the applicable insulation classes (e.g. class F or H).

Common Mistakes in Electric Motor Repair

Although electric motors are robust, in practice we often see the same pitfalls when repairs are carried out by inexperienced or low-cost repair shops:

• Use of incorrect wire types or insulation materials

• Incorrect or inaccurate winding ratios

• Poor resin impregnation, leading to short circuits

• No balancing check of the rotor or fan

• No final testing under load or for durability

Our tip: always choose a partner with experience, proper testing equipment, and knowledge of IEC standards. Electric motors are precisely engineered; a small deviation can have major consequences in operation.

Costs and Lead Time

The cost of repairing or rewinding an electric motor depends on:

• Power rating and construction type of the motor

• Extent of damage or contamination

• Urgency of the request

• Application (for example, ATEX motors or submersible motors require specialized work)

As a guideline: an overhaul is on average 40–70% cheaper than purchasing a new motor and often results in a fully restored drive within 1–2 weeks.

Our Experience: Overhaul Pays Off

At EN motors, we overhaul electric motors on a daily basis for a wide range of industries, from dredging installations to machine building. We see that customers who opt for overhaul:

• save on costs and downtime

• contribute to the sustainability of their technical installations

• receive motors back in top condition, often with a longer service life than before

In addition, during overhaul we can immediately modify or improve the motor—for example by adding extra protective coatings, installing better bearings, changing connection options, or improving the efficiency class (e.g. upgrading to IE3).

Repairing and rewinding electric motors is a smart and sustainable solution for companies that want maximum control over costs, performance, and availability. By choosing a thorough overhaul by a specialized partner, you extend the service life of your motor and improve the reliability of your entire installation.

Would you like to know whether overhaul is also worthwhile for your motor? Feel free to contact us—we are happy to think along with you.