A direct current motor (DC motor) is an electrical device that converts electrical energy to mechanical energy. A DC motor's input electrical energy is direct current, which is converted into mechanical rotation. In this session, we'll learn about DC motors and their different parts and applications.
Different parts of DC Motor
Stator
The stator is the stationary part of the DC motor, and its primary function is to generate the magnetic field. The stator consists of two or more magnetic poles. The stator established two poles, north and south poles, which interact with the rotor to produce torque. These poles are made up of either permanent magnets or electromagnets. The stator consists of field winding. The field windings are wound around the stator poles. When current flows through these windings, it generates a strong magnetic field that interacts with the rotor, causing movments. Field windings are connected in series or parallel with the motors.
Rotor
The rotor is the dynamic portion of the DC motor that is also called an armature. It consists of a cylindrical core made up of laminated steel. In this motor, different slots are made at the core of the rotor to accommodate the windings. These windings are made of copper wire and are wound into the slots of the rotor's core. When current flows through these windings, it generates a magnetic field around the rotors, which interacts with the stator and causes rotational movement.
Commutator
The communtator is another imrptoatn part of the DC motor. It is made up of hard drawn copper segments that have been mica insulated. The priamry function of commutaor is to deliver electrical current to the aramature windiing. It is a split ring device that is connected to the aramature windiing ad rotates with them. When the armature crosses a magnetic pole, the current throungh the windiing are reverses ad the motors torwue is maintained. This reversal of the current keep force applied to the rotor in the same direrction, ensuring smooth rotation.
Brushes
DC motor brushes are made of graphite and carbon and serve to transfer current from an external power source to the commutators. Brushes are mounted on the motor housing and make sliding contact with the commutator. As a result, we conclude that the commutator and brushes are responsible for transmitting power from the static current to the mechanically rotating region or rotor. Brushes wear out over time due to friction with the commutator and must be replaced frequenlty. It also generates noise and causes power losses. Regular inspection for wear and tear as well as clening to remove debris or dust build up can have a significant impct on the motor's effiecinecy.
Armature
When examining a DC motor, the armature is a critical component that converts electrical energy into mechanical motion. Armature construction is a critical aspect that directly impacts the motor's efficiency and performance. Typically armatures have a core made of thin, insulated metal sheets that are stacked to form the armature's body. This construction allows for the creation of a magnetic field essential for the motor's operations.
The torque, speed, and overall functionality of a motor are heavily influenced by its armature's winding techniques. The winding process involves wrapping copper wire around the armature core to form multiple coils that strengthen the magnetic field. The number of windings, wire gauge, and winding pattern all have a significant influence on the motor's charcteristics. Engineers can tailors the motor to specific requirements by carefully selecting the appropriate winding technique, resulting in optimal performance in a variety of applications.
Applications of DC motors
Shunt DC Motors
- Centrifugal and reciprocating pumps
- Lathe machines
- Blowers and fans
- Drills
- Fans
- Windscreen wiper drives
- Machine tools
- Milling machines
- cranes
- Conveyors
- Hoist
- Elevators
- Power tool
- Hair dryers
- Winching systems
- Electric locomotives