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What is a DC Motor?

We often use a wide variety of battery-powered electrical devices that transform electrical energy into mechanical energy on a daily basis, including hairdryers, toy vehicles, small fans, trimmers, and more. Direct Current (DC) motors are the electrical component responsible for converting that energy in order to produce movement. A type of electric machine, DC motors take electrical power through a direct current and transform it into mechanical rotation. These motors are significant in the industrial sector and can be utilized in a number of applications, including electric vehicle propulsion, elevators, cranes, and steel rolling mill drives. Those interested in learning more about DC motors and their working principles are encouraged to read the following blog.

DC motors are often cylindrical devices featuring a shaft that extends out of them, rotating once a direct current is applied. They feature a number of components, including a stator, magnets, armature, field coil, commutator, and brushes. To start, the stator, also called a steel yoke, is a cylindrical metal casing which houses all of the other DC motor elements. Stators possess two faces, the first of which features a vertical shaft coming out of it, while the second face features two terminals that the DC power supply connects to. Next, the magnets of a DC motor are stationary, permanent components installed inside the stator, and they establish a horizontal, magnetic field across their north and south poles. A third part of the DC motor is its armature which is a structure of rotating coils powered by electromagnetic force; more specifically, the armature consists of a rotor placed between the two magnets. A rotor is a structure of laminated discs wrapped with a conducting field coil, and the shaft outside of the motor passes along the axis of the armature and rotates as well.

Another DC motor part is the field coil which consists of a copper wire coil that ends up replacing the permanent magnets inside the stator walls. When DC from a battery moves through the coil, it creates an electromagnet featuring adjustable polarity in order to establish a magnetic field. Next, the commutator is a hollow cylindrical piece that is segmented to reverse the polarity of the electromagnetic armature coil inside the DC motor. Located at the end of the armature around the shaft, the armature coil is connected to the commutator, while all other parts of a DC engine are not in electrical contact with the commutator. The final DC motor part is the brush which connects the static terminals to the rotating sections of the motor. Often constructed of carbon graphite, a known conductor, the commutator is placed between the two brushes that are connected to the terminals of the motor, and this completes the circuit with the DC power source.

DC motors operate on the working principle that when a current-carrying conductor is positioned inside a magnetic field, it experiences a magnetic force, and the direction this force moves is determined by Fleming’s Left Hand Rule. This rule is known as a mnemonic tool which is utilized to comprehend the perpendicular relationship between the current, an applied magnetic field, and the force created in an electric motor. Using your left hand, you can extend your index finger, middle finger, and thumb perpendicularly. This aligns the middle finger with the conventional direction of the current and the index finger with the applied magnetic field. Finally, the thumb shows the direction of the force the conductor undergoes.

Purchasing Union is your one-stop shop for all your DC motor part needs, and with AS9120B, ISO 9001:2015, and FAA AC 00-56B accreditation, you can count on the quality of our offerings. We are proud to offer more than 2 billion new, used, obsolete, and hard-to-find parts available on our database, many of which are subject to rigorous quality control measures to ensure their reliability. Moreover, all of our components are only sourced from leading global manufacturers, and with our supply chain network spanning across the United States, Canada, and the United Kingdom, we are able to expedite shipping times for both domestic and international customers. Feel free to call or email us with any questions you may have regarding our parts procurement process.


September 23, 2022

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