Insulating Varnish and type of Varnishes Varnish is a clear transparent hard protective finish or film. Insulating Vanish is Widely used in turbo generators, industrial machines, electrical motors, power transformers, high and low voltage switchgears, motor control, gear and rewinders etc. Insulating varnishes are thermosetting resins such as epoxies or phenolics. They are used to ensure that electrical devices, including motors, generators, transformers, sensors, and other devices that function by electromagnetic induction, have the necessary electrical insulation and structural integrity for operation. Red Insulating Varnish is a highly insulating coating with excellent arc and corona resistance. This low viscosity, one-part varnish coating is easy to use and adheres well to many substrates. Applications & Usages. Used in transformers, coils, armature, motor windings, and various electric equipment’s. How to apply? There are four main methods of applying varnishes for insulating purposes • • • •
spraying for surface insulation brushing for surface insulation dipping (hot or cold) vacuum impregnation.
The varnish is used for the following purpose: • •
• •
To bond the whole winding, wires and insulation mechanically, into a solid cohesive mass, so that it is made more resistant to shock, vibration and mechanical stress. To improve the electrical properties of the fibrous or other insulators which should remain unimpaired by any of the various destructive influences over a period at least as long as the designed life of the component. To protect the winding against the destructive effects of oil, acid and other chemicals, petrol, damp, heat and mound growth and to provide anti-tracking properties. To seal all fibrous or hygroscopic materials in the winding against the absorption of moisture.
Advantages: • • • •
Can be stored up to 80 C. Compatible with most normal insulation systems. Tough, flexible, anti-tracking finish, resistant to oil and moisture Resistant to alkali, acids, solvents, transformer oil etc.
Types of Varnish