Turbogenerator Capabilities
NEC Engineers have led the industry in addressing a number of design-related issues that have emerged in the newest generation of large air-cooled generators.
- Stator winding manufacture
- Testing, inspections and life assessments
- Stator rewinds
- Core restacks and repairs, Partial or Complete
- Parallel ring modifications
- Main-Neutral Interchanges
- Stator winding end turn support modifications
- Rewedges, wedge tightening
- Through bolt retightening and hardware replacements; through bolt replacements
- Field testing of large generators for confirmation of performance parameters
- Full redesign of generator stator core and on-site or in-shop restacking
- Analysis of stator frame structure and measures for eliminating deficiencies
High-Speed, Cylindrical Rotors
- Rotor winding manufacture
- Testing, inspections and life assessments
- Collector Ring Machining
- Fan Repairs/Replacement
- Radial lead stud replacement
- Slot Wedge replacement
- Supply or repair magnetic or non-magnetic retaining rings
- Rotor tooth top cracking repair
- Calculations to determine the proper shrink fits of rotor components
- Calculations involving stress, flexure, fatigue, and fracture mechanics
- Static electrical testing of generator rotors
- Evaluation and determination of fatigue life; redesigns
- Retaining Ring Modifications, Short or Long Types
- Leak Testing & Modification of Rotor Radial Lead Assemblies
- Field Crossover Replacements
- Improvements to Enhance Vibration Stability
- Design and implementation of the direct end turn cooling systems
- Electrical Testing
- Replacement of end turn blocking
- Replacement, repair, re-insulation of individual turns of coils.
- Removal, cleaning and re-insulation of existing copper winding.
- Manufacturing new coils using OFHC silver-bearing copper.
- New slot liners and insulating materials
- Main leads, studs and stud seals
- Replacement retaining rigs, slot wedges, fans
- Collector ring repair or replacement
- Redesign to eliminate problems
- Complete rewind of rotor
- Dynamic balancing of rotor at rated speed plus momentary 10% overspeed
- Manufacturing of complete new rotor
- Vibration analysis of high-speed flexible generator rotors at all dynamic mode shapes, two and three bearing machines
- Dimensional checking of generator rotor components and calculations to determine proper interference fits