What insulation type is indicated by the letter 'V'?

The insulation type indicated by the letter 'V' corresponds to varnished cambric. Varnished cambric is a type of insulation that is made from cotton fabric that has been coated with a varnish. This treatment not only enhances its electrical insulating properties but also provides some degree of moisture resistance and durability.

Varnished cambric is often used in electrical applications where flexible insulation is needed, especially in motor windings and transformer applications. Its ability to withstand heat and electrical stress makes it a suitable choice for various electrical components.

In contrast, rubber (another form of insulation), thermoplastic, and asbestos serve different purposes or have different characteristics. Rubber is typically used for its flexibility and is often found in power cords and flexible cables, while thermoplastic is a category of materials that can be molded and remolded upon heating. Asbestos has been largely phased out of electrical insulation use due to health concerns and is not commonly utilized in modern electrical applications.