AGTServices, Inc.

Stator Winding
Surface Discharge
www.AGTServices.com
518.843.1112 or 24-hr
518.857.8306
AGTServices,
ervices Inc.
Generating timely repair solutions
Surface Discharge Summary
• End winding surface discharge
– “CORONA”
• Slot section surface discharge
– “BAR VIBRATION SPARKING”
– Can lead to SPARK EROSION
• Either way
– High frequency / low energy (?)
– Slow growers (?) / damage over time
AGTServices,
ervices Inc.
Generating timely repair solutions
Why surface discharge?
• Two surfaces with voltage
differential
• Gap
– Air or H2 Insulation
• Voltage builds to levels that gap
can’t sustain
• Voltage discharges across the gap
Kinda like a “Spark Plug”
AGTServices,
ervices Inc.
Generating timely repair solutions
So what?
• High frequency (K-Hz. / M-Hz.)
• Low energy (usually)
• Can degrade semi-con & binder
• Can degrade insulation over time
Un-like a “Spark Plug”
AGTServices,
ervices Inc.
Generating timely repair solutions
End Windings
AGTServices,
ervices Inc.
Generating timely repair solutions
Grounding & Grading 101
AGTServices,
ervices Inc.
Generating timely repair solutions
Think “Spark Plug”
AGTServices,
ervices Inc.
Generating timely repair solutions
AGTServices,
ervices Inc.
End Winding Corona / Poor Spacing Generating
timely repair solutions
EW Corona @ Phase Break
AGTServices,
ervices Inc.
Generating timely repair solutions
EW Corona / Poor Spacing
AGTServices,
ervices Inc.
Generating timely repair solutions
Top to Bottom Bar Corona
AGTServices,
ervices Inc.
Generating timely repair solutions
Top to Bottom Bar Corona
AGTServices,
ervices Inc.
Generating timely repair solutions
EW Corona & Contaminates
AGTServices,
ervices Inc.
Generating timely repair solutions
EW Corona & Contaminates
AGTServices,
ervices Inc.
Generating timely repair solutions
How to stop / fix?
• Increase gap
• Sustains the voltage
• Eliminate gap
• Short it out
• “Foul” the area
• Bleeds off voltage
Think “Spark Plug Failure”
AGTServices,
ervices Inc.
Generating timely repair solutions
Close the Gap
AGTServices,
ervices Inc.
Generating timely repair solutions
Gap Eliminated
AGTServices,
ervices Inc.
Generating timely repair solutions
Corona Bridges would Have
Been Effective as Well
AGTServices,
ervices Inc.
Generating timely repair solutions
Corona Resistant Paint
AGTServices,
ervices Inc.
Generating timely repair solutions
Slot Section
AGTServices,
ervices Inc.
Generating timely repair solutions
Grounding & Grading 101
AGTServices,
ervices Inc.
Generating timely repair solutions
Mica
Insulation
Side
Ripple
Spring
Side
Ripple
Spring
Semi
Conductive
Armor
Slot
Cross
Section
Semi
Conductive
Armor
AGTServices,
ervices Inc.
Generating timely repair solutions
Why slot discharge?
• Two surfaces (bars & core) tied
together electrically by semi-con armor
• Loose wedges allow for bar vibration
• Surfaces lose contact due to vibration
– Voltage builds
– Voltage discharges across gap
AGTServices,
ervices Inc.
Generating timely repair solutions
Puncture
Slot Discharge Damage
Painted Semi Con Layer
AGTServices,
ervices Inc.
Generating timely repair solutions
Slot Discharge Damage
Tape Semi Con Armor
AGTServices,
ervices Inc.
Generating timely repair solutions
Slot Discharge Damage
Tape Semi Con Armor
AGTServices,
ervices Inc.
Generating timely repair solutions
Slot Discharge Damage
Tape Semi Con Armor
AGTServices,
ervices Inc.
Generating timely repair solutions
Slot Discharge Damage
SRS
Discharge
Damage
Side
Ripple Spring
AGTServices,
ervices Inc.
Generating timely repair solutions
Slot Discharge Damage
New
Damaged
SRS
Side&Ripple
Spring
AGTServices,
ervices Inc.
Generating timely repair solutions
Slot Discharge Damage
Side Ripple Spring
AGTServices,
ervices Inc.
Generating timely repair solutions
PD ProductsProducts
Slot Slot
Discharge
AGTServices,
ervices Inc.
Generating timely repair solutions
Slot Discharge
Products
Slot PD Products
AGTServices,
ervices Inc.
Generating timely repair solutions
Slot Discharge Products
AGTServices,
ervices Inc.
Generating timely repair solutions
How to avoid slot discharge?
discharge
• Loose wedges allow for bar vibration
• Bar vibration allows for slot discharge
•MAINTAIN A TIGHT
WEDGE SYSTEM
Demand Side Ripple Springs
AGTServices,
ervices Inc.
Generating timely repair solutions
24 Sam Stratton Road
Amsterdam, NY 12010
518-843-1112
mike@agtservices.com
www.agtservices.com
AGTServices,
ervices Inc.
Generating timely repair solutions