SOLUTION

Electromagnets use electricity to create their power of magnetism. Electricity moving along the straight wire creates a magnetic field. This magnetic field gets weaker as it moves away from the wire. But if the wire is coiled, the magnetic field is forced back toward the wire and it becomes stronger. Electromagnets are made of coils of wire called solenoids. DC electromagnet is preferred for noiseless operation.

DC Motor Pros:

1. It is capable of providing the high starting torque
2. DC motor allows smooth quiet control over a wide range of speeds.
3. Cheaper motor speed controls. They are also simple and more reliable.

DC Motor Cons

1. Maximum torque is limited by commutation and not by heating as in other motors.
2. Contact between the brush and commutator is by arcing and high currents to the armature to another segment of the commutator. This sparkling, in course of time, causes pitting and has advanced a lot to reduce wear and tear and maintenance costs.
3. The brush and commutator requirement makes the dc motor expensive.
4. A basic requirement for a motor is high torque and low inertia (mass) or a high torque to inertia ratio. This is achieved by reducing the diameter and increasing the length. Again, modern technology has produced low-weight rotors and ironless rotors, i.e., electronic rotors.