Be it a forced or planned outage, Keystone responds to customer needs for rotor services in a swift, effective manner. Inspections, Electrical testing, Rewinds, Mechanical repairs and Retaining ring replacements are but of few of the tasks Keystone’s experienced staff provides customers for generator rotors.

Visual inspections

• Inspection of tooth tops and wedges for stress cracking
• Inspection for loose wedges and/or balance weights
• Inspection of retaining ring fit for arcing or burning
• Inspection of collector rings for discoloration or wear
• Journal inspections
• Inspection of cooling passages for blockage
• Radial lead inspection
• Visual inspection of blower assemblies

Mechanical Testing

• Rotor bore pressure test to check radial lead seals
• Boroscopic inspections
• Journal dimensions and run outs

NDE

• UT & PT retaining rings/zone rings
• UT & PT blower hubs/couplings/shaft ends
• Boresonic inspections
• Tooth top inspections

Electrical testing

• RSO testing of rotor winding
• Short and/or ground locations
• Step impedance/pole balance
• DC resistance measurement
• Insulation Resistance

Repairs

• Complete rotor rewinds with class F insulation including high or low speed balance
• Retaining ring replacement
• Journal machining on or off site
• Collector ring changeout
• Radial/axial lead refurbishment/replacement
• Repair top turn migration and/or cracking (GE)
• J-strap and/or coil crossover replacement (GE)
• Pole crossover replacement (WH)
• Repairs of turn-to-turn shorts and/or grounds