Hydroelectric Generator Repair

Supporting New England’s large & small hydroelectric generator systems

For more than 40 years, Leppert-Nutmeg has been New England’s choice for hydro generator repair.  These decades of experience have cultivated a hydro generator repair team with unparalleled craftsmanship and attention to detail.  When Leppert-Nutmeg performs generator winding, you can expect  decades of quality power production.

Hydroelectric Generator Systems

Our attention to detail means that repairs by Leppert-Nutmeg are more cost effective than many big name hydro generator repair shops.  Leppert-Nutmeg’s superior repair work means stator coil windings and insulation system procedures exceed industry standards, providing you with markedly improved performance and unit longevity. 

Exceeding industry standards
Leppert-Nutmeg understands the financial investment required for hydroelectric generator repair & maintenance.  That’s why our work regularly exceeds industry standards, resulting in hydro generators that can provide  years of power generation. 

  • Class F insulation system design exceeds industry standards
  • Detailed coil design & installation that virtually eliminates corona discharge 
  • When possible, increased amounts of copper used to improve performance
  • Better coil blocking and bracing to minimize insulation degradation & extend the unit’s life
  • VPI of rotor field poles to give the field poles greater strength and improve the longevity
  • Winding redesign for increased voltages and/or output.
  • Epoxy varnish and insulating paints for tough, durable coating with excellent insulating properties.  Utilize industry leaders like Dolph’s & Von Rolls
  • Rigorous in process testing on each rotor field pole during reinsulation and stator coils during installation.

Typical turn around for a rewind is 8 weeks with some units done in as little as 4 weeks.

Hydro generator specialists
We routinely service high capacity MW generators and perform wind generator repair, but our longevity in the industry gives us special expertise in older, small hydroelectric generator repair.   Hydro owners and power producers throughout New England bring their small hydro generator units to Leppert-Nutmeg because of our reputation for improved maintainability and generator reliability. 

With the northeast’s aging infrastructure, Leppert-Nutmeg has developed a niche service repairing older, small hydro generators.  Many of the units we repair are 100+ years old, presenting unique challenges of remanufacturing parts that are no longer in existence and rewinding units without original electrical performance data.  Despite these challenges, older hydro generators routinely leave our shop  with improved performance. 

We also recognize the importance of maintaining the historical significance of these older hydro generators.  When working on older units, we can restore them to their original configuration, enabling plants to keep their status as registered landmarks.

Hydro Generator Service and Repairs

  • Leppert-Nutmeg services generators of all sizes and ages. 
  • < 1MW to 15 MW capacity generators
  • From trend analysis of brand new units to overhauls of generators 100+ year-old
  • Turnkey onsite service:  From component replacement to disassembly, repair work to reassembly & unit testing
  • Stator, rotor, exciter and bearings repair & replacement

Repair Specs

StatorRotorsBearing OverhaulsExcitersAuxiliary Services

Stator Rewind Services

  • New rewinds
  • Repair damaged coils
  • Replace laminations
  • Surge ring upgrades & installations
  • Iron repair
  • Dry Ice Cleaning
  • Installation of RTD’s