Question

The effect of using split rings in a simple $DC$ motor is that

• A. The direction of rotation of the coil is reversed.
• B. The current in the coil always flows in the same direction.
• C. The direction of the current flowing in the coil is reversed
• D. None of these

Answer 1

The correct option is C The direction of the current flowing in the coil is reversed

Answer is C.
The direct current (DC) motor is one of the first machines devised to converts electrical power into mechanical power. Permanent magnet (PM) direct current converts electrical energy into mechanical energy through the interaction of two magnetic fields. One field is produced by a permanent magnet assembly, the other field is produced by an electrical current flowing in the rectangular coil ABCD, through the brushes and split-ring commutators. These two fields result in a torque which tends to rotate the coil. As the coil turns, the current in the winding is commutated to produce a continuous torque output.
The split ring commutator is made from 2 pieces of copper that are held apart in the center from touching each other. They look like a copper ring split in the middle.
Hence, The effect of using split rings in a simple DC motor is that the direction of the current flowing in the coil is reversed.