What is a brushed DC motor and its construction.
1 Answer
A brushed DC motor (also known as a DC brushed motor or simply a brushed motor) is a type of electric motor that uses direct current (DC) to generate mechanical motion. It is one of the simplest and most common types of electric motors, commonly found in various applications such as household appliances, power tools, robotics, and automotive systems. While they are widely used, more modern designs like brushless DC motors (BLDC) are becoming more popular due to their advantages in efficiency and reliability.
Construction of a brushed DC motor:
Armature: The central rotating part of the motor is called the armature. It consists of a core made of stacked steel laminations to reduce eddy current losses. The armature winding is wound around the core and is connected to the commutator.
Commutator: The commutator is a cylindrical segment that is mounted on the armature shaft and is electrically insulated from it. It consists of a series of segments (usually two) that are connected to the armature winding. The commutator reverses the direction of current flow in the armature winding as it rotates, which produces the continuous rotation of the motor.
Brushes: Brushes are typically made of carbon or graphite and are spring-loaded against the commutator segments. They provide electrical contact between the stationary part of the motor (stator) and the rotating commutator. As the commutator rotates, the brushes maintain contact and transfer electrical current to the armature winding.
Stator: The stator is the stationary part of the motor and consists of permanent magnets or electromagnetic windings. In simpler brushed DC motors, permanent magnets are often used to create the magnetic field that interacts with the armature winding.
Housing: The motor components are housed within a protective casing made of metal or plastic. The housing provides physical support and protection for the internal components.
Working principle:
When an external voltage is applied across the brushes, a current flows through the armature winding. The current interacts with the magnetic field created by the stator, resulting in a mechanical force that causes the armature to rotate. As the armature rotates, the commutator segments come into contact with the brushes, reversing the direction of the current in the armature winding. This reversal of current direction causes the armature to continue rotating in the same direction, creating continuous motion.
Brushed DC motors are relatively simple and inexpensive but have some disadvantages, such as brush wear, limited efficiency, and electromagnetic interference. Brushless DC motors (BLDC), which use electronic control and do not rely on brushes and commutators, have become more popular in many applications due to their improved efficiency and reliability.
Construction of a brushed DC motor:
Armature: The central rotating part of the motor is called the armature. It consists of a core made of stacked steel laminations to reduce eddy current losses. The armature winding is wound around the core and is connected to the commutator.
Commutator: The commutator is a cylindrical segment that is mounted on the armature shaft and is electrically insulated from it. It consists of a series of segments (usually two) that are connected to the armature winding. The commutator reverses the direction of current flow in the armature winding as it rotates, which produces the continuous rotation of the motor.
Brushes: Brushes are typically made of carbon or graphite and are spring-loaded against the commutator segments. They provide electrical contact between the stationary part of the motor (stator) and the rotating commutator. As the commutator rotates, the brushes maintain contact and transfer electrical current to the armature winding.
Stator: The stator is the stationary part of the motor and consists of permanent magnets or electromagnetic windings. In simpler brushed DC motors, permanent magnets are often used to create the magnetic field that interacts with the armature winding.
Housing: The motor components are housed within a protective casing made of metal or plastic. The housing provides physical support and protection for the internal components.
Working principle:
When an external voltage is applied across the brushes, a current flows through the armature winding. The current interacts with the magnetic field created by the stator, resulting in a mechanical force that causes the armature to rotate. As the armature rotates, the commutator segments come into contact with the brushes, reversing the direction of the current in the armature winding. This reversal of current direction causes the armature to continue rotating in the same direction, creating continuous motion.
Brushed DC motors are relatively simple and inexpensive but have some disadvantages, such as brush wear, limited efficiency, and electromagnetic interference. Brushless DC motors (BLDC), which use electronic control and do not rely on brushes and commutators, have become more popular in many applications due to their improved efficiency and reliability.