Q4Electrical Materials
Question
Q.4. Write properties of electrical insulating materials.
Answer
Good insulating materials require high resistivity and dielectric strength, low dielectric loss, adequate mechanical strength, thermal stability at operating temperature, and resistance to moisture and chemical degradation.
The desirable properties of electrical insulating materials are: high volume and surface resistivity (to minimize leakage current); high dielectric strength (to withstand operating and transient voltages without breakdown); low dielectric loss factor (tan δ, to minimize heating in AC fields); adequate mechanical strength and flexibility appropriate to the application; good thermal stability and appropriate temperature class rating (retaining properties at the machine's operating temperature over its design life); low moisture absorption (since absorbed water sharply degrades insulating properties); and chemical inertness/resistance to oils, ozone, and environmental degradation over the intended service life.