IPS HydroCoil — Engineering

IPS HydroCoil - Coil Drawing

HydroCoil Stator Coils —
designed to increase hydro generator reliability

Hydro generators are designed to have multi-turn, form-wound stator coils. The generators 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 a hydro generator.

All HydroCoil B-Stage Hard Coils are designed and manufactured to IPS specification with regards to insulation materials and manufacturing processes.  The HydroCoil design is validated thru industry-leading qualification testing to prevent strand-to-strand and turn-to-turn shorts which may result from voltage surges. The ground wall insulation contains multiple layers of half-lapped, resin-rich Mica tape, engineered for your specific voltage requirements. On 6.6 kV and higher voltage ratings, 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.

IPS Coil Testing

HydroCoil design validated through extensive 3rd party qualification testing

30+Year Rewind Design

Hydro industry and IPS engineers have designed HydroCoil rewinds for a 30+year life cycle by incorporating processes and materials that increase your hydro generator winding 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…)

Highest ground wall insulation density

The HydroCoil is custom engineered and employs advanced resin-rich tapes and processing methods for enhanced thermal cycling and improved dielectrics.  The processing methods are optimized to increase ground wall density (g/cm3) and ensure complete resin migration. The design and engineering combine to create a void-free coil, preventing delamination and any microvoids that can result in partial discharge activity and subsequent insulation deterioration. These fully cured and homogenized coils also prevent shrinkage, which means no re-wedging is required.

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 generator to run cooler) — all of which extend the service life of the hydro generator. In addition, HydroCoil’s improved dielectrics and thermal dissipation means hydro generator rewinds can typically offer an increase in generator rating, permitting higher output power generation levels.

IPS HydroCoil Cross section

Coil cross section – HydroCoil offers the highest Mica density (g/cm3), resulting in industry leading coil dielectrics.

IPS HydroCoil no voids

Magnified coil cross section shows uniformly compressed tapes absent of puckers and voids

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