By cascade operation

By rotor rheostat control

By injecting emf in rotor circuit

By changing the applied frequency

Open circuit and short circuit

Closed circuit and open circuit

Short circuit and closed circuit

Control circuit and power circuit

Non moisturized material

Highly non-hygroscopic

Very good for class F insulation

Better ageing and dielectric strength

Cotton sleeves

Empire sleeves

Terylene thread

Fibre glass tape

Fibre glass tape

Leatheroid paper

Empire fiber glass tape

Fabric based adhesive tape