What is the purpose of the fields of a dc shunt motor?

Answer 1

DC Shunt motor: dc shunt motor is a motor with dc supply given to the inductor connected in parallel with the armature of a motor. The inductor connected in parallel with the armature of a motor called field winding of a motor.

In dc shunt motor: When current flows through a conductor ( here it is armature in case of dc shunt motor ), magnetic field is produced which is circular and when this conductor is placed perpendicular in the magnetic field ( which is produced by the current or say dc supply that given to the inductor or say field winding of the dc shunt motor ), the main magnetic lines get bent due to the interaction of the two fields. These lines of force experience tension and try to become straight. So, a force is produced on the conductor ( armature ), due to which the conductor ( armature ) will rotates. The direction of force can be found by Fleming's right hand rule.

Main Answer: Thus, it should be understood that field winding in dc shunt motor stands to get interaction of the two field in such a way that force is produced on the armature so that the armature get to rotate.

Some Facts: Actually the current in armature is due to the mutual induction by field winding to the armature. That means only field winding get dc supply through which current and so magnetic field is produced in armature that try to oppose due which it is produced, that means it oppose the main magnetic field of field winding.