Gate 1 Program

Minor inspection with generator rotor in place

 
Gate 2 Program

Major inspection (rotor out) with limited testing

 
Gate 3 Program

Major inspection with extensive testing

 

Rotor Services

  • Brushless exciter test, inspection and complete overhaul

  • Field ground detector troubleshooting for both RF and Optical systems

  • Retaining Ring inspection, removal & replacement

  • Non-destructive testing (NDT) of retaining rings

  • Collector ring repair, replace, and machining

  • Complete rotor rewind

  • Post-rewind high speed balancing

  • Radial hydrogen seal replacement

  • Wedge replacement

  • Repair turn shorts

  • Terminal Stud repair & replacement

  • Endwind blocking

  • Creepage blocks

Rotor Testing

  • Insulation resistance & polarization index (“megger & P.I.”)

  • DC resistance testing

  • AC impedance test

  • Pole balance test

  • Recurring Surge Oscillography (RSO) test for shorted turns

  • Hydrogen seal pressure test for leaks

  • Borescope visual inspection

Additional Capabilities

  • Consultant services

  • Root cause analysis

  • Silver plating (electro-plating) bus work mating surfaces

Stator Services

  • End winding resonance detection and repairs “bump test”

  • Connection ring / parallel ring re-blocking & re-tying

  • End winding, re-blocking, & re-tying based on bump test & visual inspection results

  • End winding stiffening treatment

  • Corona and partial discharge activity abatement

  • Stator re-wedging

  • Flux probe installation

  • Dry ice “CO2” blasting excessively contaminated stators

  • High voltage bushing replacement

  • Temporary High voltage bushing & terminal plate leak repairs (“damming”)

  • Replacement of stand-off insulators

  • Stator core iron repairs

Stator Testing

  • Insulation resistance & polarization index (“megger & P.I.”)

  • DC Leakage test and Hi Pot

  • ELCID testing for core faults

  • Digital wedge mapping

  • Ripple / PSDS spring depth gage testing for wedge tightness

  • DC resistance testing of each phase

  • Bump test / modal analysis of end windings & connection rings

  • Corona camera

  • Doble / Tan-Delta / Power Factor testing

  • Thermographic detection of high resistance connections

  • Westinghouse / MHI inner-cooled unit testing including:

    • Transposition Testing

    • Tube to tube resistance test

    • Tube to copper resistance test

    • Core through bolt & building bolt torque checks & re-tightening

    • Megger of through bolts

    • Parallel ring flow testing

Frequently Asked Questions

How does RTS resolve recurring generator end-winding greasing and dusting issues?

RTS starts with a Bump Test to identify sections of the winding that exhibit resonance near the driving frequency, typically 120 Hz on a 60 Hz machine. Based on the results, we design a fix that can include re-blocking and re-tying to shift the unit's resonance band away from its driving frequency, along with an end-winding stiffening treatment to re-establish the epoxy bond planes and secure loose components.

What Hi-Pot test voltage does RTS recommend for an older generator?

OEMs typically recommend Hi-Pot testing at 1.5x the operating voltage (1.5xE), but for older units, RTS often recommends a more conservative 1.25xE. Testing at a lower voltage reduces risk during testing, while testing at a higher voltage builds greater confidence in future reliability. 1.25xE is usually the right compromise for a generator that has seen years of service.

My generator keeps tripping on field ground alarms. How do I know if it's a real field ground?

Start by isolating whether the issue is in the excitation system or the generator itself. On a brushless unit, RTS isolates the rotating diode wheel from the field winding and tests both sides separately. On a unit with static excitation, we remove all brushes and test the field and buswork independently. From there, RTS has a testing protocol to further investigate whether the issue is actually in the rotor circuit.