15 MVA ELIN generator rotor fully rewound in 8 weeks time!

MP’s electrical specialists have fully rewound a 15 MVA ELIN generator rotor in 8 weeks time.

ELIN DTG 100/2-227 Generator from 1966

  • Manufacturer: ELIN
  • Type: DTG 100/2-227
  • Stator Voltage: 10 500 V
  • Output: 15 MVA
  • Year: 1966

Customer’s request

The customer’s original request was to replace the original retaining rings by new retaining rings in an anti-magnetic material. MP was asked to re-engineer, manufacture and install the new retaining rings. The anti-magnetic characteristics of this material reduce leak flux (electromagnetic losses) in the retaining rings. Moreover, this material is less prone to corrosion than the original retaining rings.

Both the stator and rotor were transported to Maintenance Partners’ workshop in Zwijndrecht for overhauling.

When the rotor was dismantled, MP’s engineers found that the rotor’s insulation material was severely deteriorated. A full rewind turned out to be the only solution to ensure safe and reliable operation.


Rewinding the rotor was a very extensive project that included 300 turns that had to be installed and insulated individually.

The generator is a critical machine in the customer’s plant, because of this teams of 3 specialists worked in 2 shifts to finalize the rewinding within 8 weeks.

Engineered Services: Improvements

Besides the re-engineering of the retaining rings, Maintenance Partners’ engineering department applied two other important conceptual improvements:

  • The rigid connection between the north-south was replaced by a flexible connection
  • In the original design, there was no room for the windings to expand, the modifications now allow this

These improvements are a good example of MP’s Engineered Services: offering more than just repairs. We do so by applying high quality materials, improving designs and evaluating the functionality of rotating machines within the process.



During the rewinding of the rotor, the stator was also overhauled. To make the overhang more rigid, epoxy was injected and the original wooden winding supports were replaced by expoxy supports.


After installation of the retaining rings, the rotor was ready for balancing in MP’s high speed balancing machine. During the balancing, Repetitive Surge Oscillograph (RSO) measurements were conducted to detect any short circuits.

Result for the customer

Thanks to the reverse engineering of the rotor and stator, the generator’s relability is at the highest level. In addition, the project planning of this project has helped reducing the downtime of the generator to a minimum.

More information

Do you want to know more about the generator rewinding, repairing or re-engineering? Call us at +32(0)3541 71 40 or send us a message using the form below:

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