Special project: Full refurbishment of 15 high voltage motors

Not all motors are the same. While Maintenance Partners is a jack of many trades in terms of the repair and rewinding of motors for a wide range of customers, some projects require special attention. At the start of 2017, a European energy company with multiple power plants contracted Maintenance Partners. A customer with a special project related to high voltage motors.

Previously, Maintenance Partners had already regularly repaired electric motors for the energy company, and carried out maintenance work as a contractor. Now a different question was raised: fifteen high voltage high voltage motors needed a total refurbishment, which meant a full stripping and renewal of the machines.

Refurbishment book

A special project requires a special approach. While a test report is issued to the customer for standard revisions or rewinds, for this project a refurbishment book is drawn up for each machine: a 50-page document that, in consultation with the customer, lays down all wishes regarding the refurbishment. This book serves as a guideline that is strictly followed by all employees who work on the machine during the different phases of the refurbishment.


There are many steps between reception of the machine in the workshop and its completion. The motors, which are sent by the customer in stages to Maintenance Partners, are first subjected to a series of tests, during which all necessary information is recorded. Mechanics then fully disassemble de motor, measuring all fits. A magnaflux inspection is carried out on the shaft, looking for cracks in the material. An NDT examination is carried out on the flanges for the same reason. In addition, the winding is evaluated (number of turns, thickness of wire, rotations per minute). Various hold points and witness points are scheduled during this process: points at which the customer comes to witness, when the motor is disassembled.

Once the winding is removed from the stator, a core test is performed. The customer has asked for a new stator core, but new coils and bearings are also always provided. The entire machine is also sandblasted and gets a new coating to prevent corrosion. The core package is measured, built, lasered and stacked in the blasted casing.

This is followed by the rewinding and coupling of the electrical ends to the coils, and electrical circuits are coupled in the same way as before the disassembly. Various tests and measurements are also carried out during these phases. Finally, the motor goes to the VPI tank, where the windings are impregnated under vacuum.

After the rotor is installed again, various tests are performed to check whether everything was reinstalled correctly.

As good as new

Every motor is thus given a full makeover, that gives the customer a guarantee that the machines will be operational again for a longer period of time. An alternative, of course, is to order new machines. However, this process often takes over a year, because – in particular for these types of motors – nothing is standard, as everything needs to be tailor-made.

Refurbishing is therefore faster, and is certainly equally efficient. A refurbished motor is not inferior in terms of quality to a new motor, and often operates better than when it was first taken into use, especially the insulation thanks to the use of the best materials. The result is a motor that is as good as new, or even better!

High voltage in the industry

This also takes away the concern shared by many companies that use high voltage motors, and that are wondering whether their machine will be of the same quality after the repair or rewinding. By the way, it is not just energy company that can bring their high voltage motors to Maintenance Partners. Other industries, such as petrochemicals, food, steel and rubber production can also benefit from the solutions offered by Maintenance Partners. These motors, which may be critical to the production process, require extra attention and knowledge.

Maintenance Partners has this knowledge. The specialist in electric motors has the people and experience to take on larger scale projects.

More information

Do you want to know more about repairs of  electric motors? Visit our page about electric motors, call us at +32 (0)3 541 71 40 or send us a message using the form below:

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