Stator Replacement and Maintenance

Recently, American Society of Power Engineers (ASOPE®) documented the process of maintenance and component replacement on a 650 mw General Electric unit. Units of these kind are commonly used in wind power generation applications. The generator required a variety of inspections and maintenance to ensure it was to spec and ready for use in the field.

For this particular GE generator, the primary focus was the maintenance of stator windings. The most common failure of these windings are loose stator bars in slots, stator bar insulation deterioration, and thermal cycling. A licensed ASOPE® Power Engineer has the training and expertise to correctly maintain these types of generators and properly inspect, replace, and repurpose stator windings and bars. Provided are photos and descriptions of the process used by a licensed ASOPE® Power Engineer to properly get this generator back in the field.

Power Engineer Begins Disassembly for Stator Bar Replacement

Disassembly begins on
stator bar replacement

ASOPE Power Engineer Undoes Brazing on Stator Bars

Undoing the brazing of the
bars and loop leaves.

Removal of Ripple Springs from Stator Bar and Core Iron

Removal of ripple springs from between the bar and core iron.


Power Engineer Removing Core Slot Wedges

Cutting and removing
core slot wedges.

ASOPE Licensed Power Engineers Removing Top Stator Bars

Carefully removing top bars.

Power Engineer Removal Top Stator Bar from Generator

Top bar removal from
turbine end of generator.

All 18 top bars and
bottom bar #33 removed.

18 top bars ready for inspection test.

Four top bars to be
reused after Hi Pot test.

An ASOPE Power Engineer Preps Suppressor Areas for Stator Bars

Prepping suppressor
areas on original bars.

Repairing Slot Section Armor Tape on Stator Bars

Repair slot section armor tape on original bars.

A Power Engineer with Inspection Credentials Inspecting Stator Core

Stator core slot section inspection prior to bar assembly.

Cleaned and Prepped End Windings for Bar Assembly

End windings cleaned and prepared for bar assembly.

ASOPE Power Engineers Installing New Bottom Stator Bar

New bottom bar installed in slot #33.

A Power Engineer Installs a New Top Stator Bar

New top bar install.

ASOPE Power Engineer Team Installs Final Stator Bars

Final bar installed.

Assembled and Brazed Bar Clip Leaves

Assembling and
brazing bar clip leaves.

Cleaned Plumbing Components Ready for Assembly

Plumbing cleaned and
prepared for assembly.

A Power Engineer Inspects Epoxy Brazing

Inspection of epoxy
injection after leaf brazing.

A Team of Power Engineers Inspecting New Epoxy Injection Clips

Inspection of new epoxy injection clips for final install.

ASOPE Power Engineers Recording Clip Inspection on Video

Recording clip internal
inspection on video.

Baking of Clips Following Epoxy Injection

Epoxy injection completed.
Baking of clips begins.

ASOPE Power Engineers Pressurizing Components with Helium

Pressurizing with Helium to check epoxy injection integrity.

View of Piping Assembled and Brazed

Piping assembled and brazed.

Leak in Plumbing Repaired and Rebrazed Following ASOPE Inspection

Leak at bar #20 found in plumbing, repaired and rebrazed.

View of Mica Tape on Loops

Mica tape on series loops CE.

A Power Engineer Assembling Nose Rings

Assembling nose rings.

A Power Engineer Performing Ultrasonic Test During Flush Operations

Ultrasonic test performed
during flush operations.

Stator Wings Being Baked and Prepped for 12 Hours

Stator wings baked at
100 deg C for 12 hours.

A Power Engineer Disconnects and Grounds RTD's

Disconnecting and grounding RTD's.

ASOPE Licensed Power Engineers Assembling Core Slot Wedges

Assembling core slot wedges.

A Power Engineer Re-Installs a Flux Probe

Flux probe re-installation.

A Power Engineering Team Ties Bars and Tension Members in End Windings

Tying bar and tension member
ties in end windings.

End Windings Blocked and Tied

End windings completely
blocked and tied.

ASOPE Power Engineers Applying Flooding Resin

Applying flooding resin
epoxy to coat end windings.

Finalized End Shield Ready for the Field

Inner End Shield in place ready for field.