INSULATING VARNISH

Category

CONSTRUCTION, VARNISH

About This Project

KEYPOINT :

  • Protects and Insulates various electric parts against arc and rust.
  • Insulation Class H – Suitable for service up to 180 °C
  • High dielectric strength – 3 000 V/mil (dry); 1 500 V/mil (wet)
  • Excellent finish—tough, flexible, glossy, and durable red coat
  • Good adhesion and good water and salt water resistance

GENERAL :

After a motor is rewound, the windings must be further insulated with resin or varnish.  This insulation protects the windings from contamination, shorting electrically, and also make the windings more mechanically rigid. There are four types of varnishing methods that we will describe below: Dip and Bake Epoxy Varnishing, WINSOL Varnishing, Vacuum Pressure Impregnation, and Ultra-Sealed Winding.

Dip and Bake is a standard varnishing technique where the motor windings are dipped into a varnish tank and then set to cure in an oven. Typically, a new motor winding should be dipped twice (double dip and bake) to ensure the varnish fully covers the windings.

Many repair shops do not allow the windings to cool once they are cured in the oven after the first dip and before the motor is dipped a second time. Because the windings are still hot during the second dip, the varnish becomes more viscous and runs off the motor easily. This results in a less effective second dip of varnish.

Because we want to ensure adequate varnish coverage, PHISE quality standards denote that the windings must be cool before the second dip. Our varnish is Class N and Hermetic rated, meaning the varnished used can withstand higher temperatures and is fit for compressors (respectively).