What is a commutator and its purpose?


Commutator is a kind of equipment used as electrical switch, which is often used in some types of motors, generators and DC Electric power transmission. Its main purpose is to reverse the current flowing through the motor or generator coil, thereby achieving continuous rotation.

A commutator consists of a series of copper plates, called commutator bars, installed on the rotor (armature) of a motor or generator. These rods are separated by insulating material and connected to the ends of the coil winding. Commutators are usually paired with brushes, which are fixed carbon or graphite contacts that physically come into contact with the commutator strip. It consists of two contacts, called a set of brush holders, connected together and rotating, and a moving switch type contact called a commutator blade. When the commutator blade rotates, it slides along the contact surface and changes the direction of the current in the circuit.
When current passes through the coil winding of a motor or generator, a magnetic field is generated, which interacts with the magnetic field generated by a fixed magnet or stator winding. This interaction causes the rotor to rotate. However, without a commutator, the direction of current flowing through the coil will remain unchanged, causing the rotor to only move half a turn and then stop.
Commutators are most commonly used in DC motors and generators, and they have two main functions.
Firstly, its function in reversing current allows the motor to rotate in both clockwise and counterclockwise directions.
Secondly, it serves as the insulation medium between the rotor and stator, preventing arcing between these components.
In addition, rectifiers are also used to start the power supply of electric motors, such as batteries and AC switches. This ensures a reliable current supply and prevents arcing between components.
These professional knowledge may not be well understood by ordinary people. Where can commutators be used in our daily lives?
A commutator is a component of a DC motor, such as a brushless DC motor. These motors are widely used in fields such as electric vehicles, household appliances (such as fans, blowers), electric tools, and industrial machinery.
In some types of DC generators, commutators are used to convert mechanical energy into electrical energy. These generators exist in portable power sources, backup power systems, and some renewable energy systems.
It can also be used in electric traction systems, such as electric trains, trams, and electric forklifts. These systems rely on DC motors to provide necessary propulsion.
Some smaller devices, such as certain types of toys, small appliances, and train models, may be operated using DC motors with commutators.
However, it should be noted that not all types of motors or generators use commutators. AC motors, such as induction motors, do not require commutators because they operate based on the principles of AC and rotating magnetic fields. In addition, due to its efficiency and other advantages, many modern applications and technologies have shifted towards AC based systems.
Commutators are commonly used in electric motors, so what are their specific functions in electric motors?
In the generator, the commutator ensures that the generated current has the correct magnitude and polarity. This is achieved by controlling the movement of the armature in the generator, allowing the generated current to be supplied to the electrical load. The commutator converts direct current into alternating current. This conversion is achieved by changing the direction of current flow and reversing polarity at regular intervals. This ensures that the current produces the desired effect on the electrical load.
The commutator is designed to withstand high levels of mechanical wear in the motor, as the contact surface between the commutator and the brush is constantly moving. In addition, the commutator helps to form a tight seal, ensuring that the overall operation of the device remains efficient and fault free.
Overall, a commutator is a component of an electric motor, generator, and other components that require the connection and disconnection of current. It is an important switching device that can reverse the direction of current and prevent arcing, while its design ensures that its components can withstand high levels of mechanical stress.
Ningbo Haishu Nide International Co., Ltd focuses on supplying the different kind of motor components to our customers.The products include commutator, ball bearing, shaft, carbon brush, insulation paper, thermal protector, magnet, fan, motor cover and lamination.