IPS PowerSeal – Engineering

powerseal coil drawing

PowerSeal Stator Coils —
designed to withstand the stress of severe applications

Medium voltage, AC motors and generators are designed to have multi-turn, form-wound stator coils. In these cases, the stator winding has three separate but interrelated insulating barriers: strand to strand insulation, turn to turn insulation, and ground insulation. Failure of any of these barriers will prematurely terminate the service life of the machine.

All PowerSeal coils are manufactured to IPS specification with insulation materials designed and proven thru extensive qualification testing to prevent strand-to-strand and turn-to-turn shorts which may result from voltage surges. PowerSeal stator coil ground wall insulation contains multiple layers of half-lapped high content Mica tape, engineered for your specific voltage requirements. At specified voltage designs, we also apply conductive corona tape to the slot portion of the coil to prevent corona discharges in the slot, as well as stress grading tape to help bleed the voltage to non-damaging levels. Our global VPI process completely penetrates and saturates all stator coil insulation tapes in epoxy resin homogenously at the same time, while encapsulating the entire stator winding into a solid, rugged protective mass.

4160 coil at 40 kV test

AC Hi-pot of PowerSeal 4,160 VAC stator coil @ 40+kV”

40-Year Rewind Design

PowerSeal is a Class H+ (> 180 ˚C) rated insulation system that has completed extensive internal and external qualification testing. IPS engineers have designed PowerSeal to a 40-year life cycle by incorporating processes and materials that increase your electric motor reliability and mitigates the following winding failures and aging factors:

  • Strand to Strand short
  • Turn to turn short
  • Phase to phase short
  • Grounding in the slot
  • Grounding at edge of slot
  • Shorted Connections or Leads
  • Corona Inception due to Partial Discharge (PD)
  • Mechanical Stresses (e.g. Vibration, Abrasion, Thermal Expansion…)
  • Environmental Stresses (e.g. Moisture, Chemicals, Dirt, Contaminants…)
  • Electrical Stresses (e.g. High-Voltage Applications, Voltage surge / transients…)
  • Thermal Stresses (e.g. Temperature Rise, Hot Spots, Insulation Material Degradation…)
PowerSeal vs Competition Dielectric Strength 66 kV Horz

Highest Dielectric Strength (V/Mil)

Each year, we continue to invest in PowerSeal through extensive qualification testing of new materials (e.g. tapes, resins, insulating materials…) as they become available in order to prove and validate our 5-year industry leading warranty, and 40-year rewind design. For example, IPS engineers continue to qualify newer, next generation Mica ground wall tapes in order to deliver the best dielectric strength (V/Mil) in order to keep up with newer and more power dense OEM stator designs. As insulation materials and manufacturing technologies improve, some insulation tapes have decreased in thickness while maintaining or increasing levels of Mica density. These newer, leading-edge and thinner mica dense insulation tapes are suitable for rewinding both older and newer stator designs, including those with narrow slot widths, while maintaining an acceptable dielectric (V/Mil) design.

Powerseal Cross Section Drawing

Motor efficiency gain and up-rate opportunity

IPS uses state-of-the-art insulation that provides higher mica content and a denser ground wall. The benefits are better coil dielectrics and superior heat transfer (allowing the motor to run cooler) — all of which extend the service life of the electric motor or generator. In addition, the improved coil insulation provides IPS engineers the opportunity to potentially increase motor efficiency and/or up-rate the motor.

To learn more about our services or to see how IPS can help you, contact your local service representative or email us.