Principle of D.C. Motor

Principle of D.C. Motor Points : Principle of DC Motor Motor principle is based on the principle that whenever current carrying conductor is placed in a magnetic field this conductor experiences a mechanical force whose direction will be given by Fleming’s left hand rule.

The two pole D.C. motor with field winding is energized with D.C. supply.
Hence magnetic flux will be set up which flows from N pole to S pole.
(a), With no current in the armature (rotor) winding.
(b) Shows d.c. motor with armature windings carrying current.

The direction of current in the armature coil is indicated by cross under North pole and by dot under South pole. Since it is known that, the current carrying conductor placed in a magnetic field. So these conductors will experiences force whose direction will be given by Fleming’s left hand rule. In this way each armature conductor will experience a force and accordingly d.c. motor will start rotating.

As armature conductor is the current carrying conductor, so it produces flux around it. Hence flux density increase above the conductor, which push the conductor in downward direction. The other conductor experiences a force in upward direction. There are number of armature conductor on armature core and all of them experience force and hence rotor starts rotating.