What are the functions of yoke? What is the choice of material for the yoke?

  1. It gives the mechanical support to the poles.
  2. It acts as an outermost cover of the dc machine. Thus the insulating materials get protected from moisture, dust and flammable gases.
  3. It forms a part of the magnetic circuit. It provides a path of low reluctance for magnetic flux.

Materials used for Yoke:

  • It is prepared by using cast iron.
  • For large machines rolled steel, cast steel and silicon steel is used. They provides high permeability