Generator Makes & Models No Longer Produced

NEC’s ability “reverse engineer” any generator design extends the lives of units no longer in active manufacture.

Because predecessor OEM "legacy" designs often take a back seat to the "current" OEM's designs, NEC has found a niche in serving this market. NEC design engineers have a diversity of knowledge and experience that gives our design team a wide-ranging base of experience with generating units of all ages, makes, sizes and types, including unit models that are no longer actively manufactured. Along with the winding design, our engineers address related issues of unit reliability, efficiency, maintainability and longevity. By comprehensively addressing the total machine, old units can become newly valuable as functioning assets for the generation of electricity.

Past projects have involved generator rewinds, uprates or repairs to rotating electrical equipment manufactured by nearly every supplier in the world. A partial list includes:

  • GEC
  • Allis Chalmers
  • Peebles
  • Elliott
  • English Electric
  • Parsons
  • KWV
  • Asea
  • Brown Bovari

These projects have services turbogenerators, hydrogenerators, AC and DC motors, exciters, frequency changes and synchronous condensers. Sizes have ranged from motors of a couple thousand horsepower, to 1000 MVA generators.

New Life to an old Generator

Increasing the stability of the grid in the southeastern part of the United Kingdom became a priority after the August 28, 2003 London blackout. To that end, a fire-ravished, 70 MW Parsons 1980s vintage generator on the Isle of Wight gained new importance for its owner, RWE Innogy, making its rehabilitation or replacement cost-effective for the first time since the 2000 fire that put it out of service. The fire started with a lube-oil system leak caused when a rotor slot wedge experienced fatigue failure and spun out of the rotor. The unit's turbines, one at each end of the generator, were not damaged. While there were clearly parts of the generator module that were non-recoverable, such as the exciter, which was greatly distorted by the heat of the fire, the rationale to junk other parts of the generator was less clear. NEC performed an extensive evaluation of all failed components was conducted, providing the owner with recommendations for repair or replacement. MORE

Stator End-Winding Support Systems
NEC has the ability to engineer and retrofit major machine components, such as the end winding support system, for units experiencing problems related to their original designs. View this Case Study.
Overhaul of a Hydrogen-Cooled Exciter
Exciters of this size are rare in the industry. NEC's RESC performed extensive refurbishment and repair to all components of this exciter, including the manufacture and installation of a new armature winding. View More about this project.
Re-qualifying Hydro Spider
A number of rotor mechanical issues should be considered and analyzed when a hydrogenerator stator winding is uprated. Bill Moore's article, Advances in Hydrogenerator Refurbishment provides a case study for a hydro spider forging that was repaired and re-qualified for return to service at our RESC.
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