(i) Dummy coil is used with wave winding when the requirement of the winding is not met by the standard armature. (ii) Dummy coil is not connected to the commutator so they do not influence the electricle characteristics of the winding. (iii) Dummy coil ends are cut short and taped. (iv) Their main use is to provide mechanicle balance for the rotar because rotar having some slots without winding would be out of balance mechanically.