Vacuum Pressure Impregnation (V.P.I.)

Vacuum Pressure Impregnation (V.P.I) is a process by which a fully wound electric apparatus stator or rotor is completely submerged in a Resin. Through a combination of dry and wet vacuum and pressure cycles, the resin is assimilated throughout the insulation system. Once thermally processed, the impregnated windings become a monolithic and homogenous structure.

The resulting benefits are;

  • Higher Dielectric Strength,
  • Increased Mechanical Strength,
  • Greater Thermal Inductivity,
  • Superior Protection against the Ingress of Water, Chemical and Containments.

A proper global vacuum pressure impregnated winding will have superior characteristics, which will support a longer and more maintenance free life span.

Avonmore Electrical is proud to offer this essential process to its customers and is also proud that this is the only such plant in Ireland and only one of a handful in the British Isles.

As part of our Information Management Systems, a detailed printout of the combined tests which have been carried out will be available to the customer.

V.P.I. PROCESS EXPLAINED

  1. ​PLACE STATOR OR ROTOR INSIDE IMPREGNATION VESSEL.
  2. SECURELY LOCK TANK AND INITIATE VACUUM PROCESS.
  3. ONCE PRESSURE IS DEVELOPED TO 50mbar THE VACUUM PUMP ALLOWS RESIN TO ENTER IMPREGNATION VESSEL.
  4. ONCE THE UNIT IS SUBMERGED IN RESIN, A WET VACUUM IS CREATED.
  5. UPON COMPLETION OF WET VACUUM, THE ELECTRICAL APPARATUS IS PRESSURISED AT 6bar/84psi. 
  6. V.P.I. PROCESS DURATION IS RELATIVE TO THE UNIT ROTOR/STATOR/COILS SIZE.
  7. ONCE THE V.P.I. PROCESS HAS BEEN COMPLETED, A REVERSE VACUUM IS CREATED IN THE RESIN TANK TO EMPTY THE IMPREGNATION VESSEL. 
  8. THE IMPREGNATED UNIT IS THEN LEFT TO DRIP, PRE-CURING. 
  9. A FULL PRINT OUT OF THE PROCESS IS GENERATED INCLUDING TIME, DATE, DURATION OF PROCESS, PRESSURE APPLIED, ETC. 
  10. THE INFORMATION IS STORED IN AIMS, (AVONMORE INFORMATION MANAGEMENT SYSTEM). 
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