1. D.C.MOTOR

2. FORCE ON A CURRENT CARRYING CONDUCTOR KEPT IN A MAGNETIC FIELD
A CURRENT CARRYING CONDUCTOR KEPT IN MAGNETIC FIELD (ONLY AT RIGHT ANGLES) EXPERIENCES A FORCE, WHOSE DIRECTION CAN BE FOUND BY FLEMING’S LEFT HAND RULE

4. PARTS OF A DC MOTOR ARMATURE COIL: IT IS A COIL OF WIRE
SPLIT RING: A COPPER RING ALSO CALLLED
AS SPLIT COMMUTATOR.
THEY MOVE WITH THE ARMATURE
COPPER BRUSHES: THEY ARE FIXED

6. WORKING OF DC MOTOR:
PLANE OF COIL IS HORIZONTAL. SPLIT RING S1 – B1, SPLIT RING S2 – B2. WHEN KEY IS CLOSED, CURRENT FLOWS IN ABCD, AB AND CD ARE PERPRENDICULAR TO THE MAGNETIC FIELD. THERE IS A FORCE. AS PER FLEMINGS LH RULE, AB MOVES DOWNWARDS AND CD MOVES UPWARDS
AT 90 DEGREES: NO CONTACT BETWEEN BRUSH BI AND S1. NO CURRENT.
COIL CONTINUES TO MOVE. NOW SPLIT RING S1 – B2 AND S2 – B1. THEY CONTINUE TO ROTATE DUE TO FLEMINGS LH RULE
270 DEGREES: NO CONTACT BETWEEN BRUSH B2 AND S1. NO CURRENT.
DUE TO INERTIA , IT CONTINUES TO MOVE