What is the working of Dc motor.
-When current flow through coil,arm AB and CD experience magnetic force.
-As per Fleming’s Left hand rule,arm AB of coil experiences force in downward direction and arm CD experiences force in upward direction.
-Here, both these forces are equal and opposite.
-Two equal and opposite forces acting at different position of armature constitute a couple.
-The couple rotate the coil in clockwise direction until the coil is in vertical position.
-At this position,the contact of commutator and brushes break.
-Supply of current to coil is cut off.And hence no force acts on arms of coil.However coil goes on rotating due to inertia of motion of coil until commutator again comes in contact with brushes.
-Now, when commutators comes in contact with brushes after rotation,direction of current in arm AB and CD is reversed.
-The force acting on arm AB is in downward direction and force acting on arm CD is in upward direction.These 2 equal and opposite forces constitute a couple.this couple rotate coil again in clockwise direction.
-The coil of d.c. motor continues to rotate in same direction.Hence electrical energy is converted into mechanical energy.