Definition
A DC motor is an electrical machine that converts direct current (DC) into mechanical (rotational) energy. It is widely used due to its simple design, high torque, and easy speed control.

Working Principle
DC motors operate based on electromagnetic force:
• When DC voltage is applied, current flows through the armature
• A magnetic field is created
• This interacts with the stator’s magnetic field
• The resulting force causes the rotor to rotate
The commutator ensures continuous rotation by reversing current direction.

Torque Relationship

Torque is directly proportional to current—higher load requires more current.

Types of DC Motors

1. Permanent Magnet (PMDC)
   • Uses permanent magnets
   • Compact and efficient
   • Used in automotive and marine systems
2. Series DC Motor
   • High starting torque
   • Speed varies with load
   • Used in starters and lifting equipment
3. Shunt DC Motor
   • Stable speed
   • Moderate torque
   • Used in conveyors and machinery
4. Compound DC Motor
   • Combines series and shunt features
   • Balanced performance
5. Brushless DC (BLDC)
   • No brushes, uses electronic control
   • High efficiency and long life

Applications
• Automotive: starters, power windows, wipers
• Marine: tilt/trim motors, pumps
• Industrial: conveyors, actuators
• Consumer: tools, appliances

Conclusion
DC motors are reliable, efficient, and versatile. Their ability to provide high torque and simple control makes them essential in automotive, marine, and industrial applications.