At a moment’s notice, Keystone’s staff of experienced generator specialists and technicians can mobilize to a site with state of the art equipment to affect a broad array of stator services. Whether the need is to test, inspect, evaluate the stator, re-stack iron, completely rewind and upgrade the stator coil support structure, Keystone provides customers with cost effective solutions to any stator problem that might be encountered.

Visual Inspections

• Core
• End-winding and support system
• Main and neutral leads
• Bushings
• Main and neutral lead box and enclosures

Mechanical testing

• Frequency response testing
• Digital wedge tightness evaluation
• Frame foot loading
• Pressure decay test
• Vacuum decay testing
• Helium leakage testing

Electrical testing

• Insulation Resistance/Polarization Index
• DC winding resistance
• RTD resistance measurements
• DC high potential testing
• Transportation testing
• Tube to tube resistance
• Vent tube/parallel ring flow testing
• Tube to copper resistance
• Electromagnetic Core Imperfection Detector Test (EL CID)
• Thermovision scan (loop test)
• Capacitance mapping

Repair services

• Rewind with new coils and class F insulation
• Rewinds with refurbished coils/ coil repair on site
• Core tightening
• Core lamination repairs
• Core lamination replacement
• End winding tightening
• Strand repairs
• Bushing repair and replacement
• Re-wedge
• Water box leak repair
• Epoxy
• Permanent mechanical repair

Modifications

• End winding support system decoupling
• Through bolt nut upgrade
• Stator coil design upgrade
• Flux probe installation
• PDA coupler installation
• Tagging compound installation