Your life basically gets controlled by technology and electric motors are more prevalent than you may think. Did you know there’s one helping to make your coffee in the morning? Yes, it’s the humble brushed DC motor.
Whether you’re curious about how these things work or if you’re looking for the ideal motor for one of your own projects, we can help you better understand them. Thanks to people’s innovative ideas there are quite a few types to consider, so pick wisely.
Before we dive in, we need to get a fundamental understanding of;
A DC Motor or Direct Current Motor is an electrical machine that converts electrical energy into mechanical energy through generating a magnetic field created by direct current. A mechanical force is generated through the interaction between magnetic field and electric field.
There are two important parts of a DC Motor, such as stator and rotor. Stator is the static part of a DC motor while rotor is the rotating part of it.
Features of a DC Motor:
Types of DC Motor: 1. Brushed DC Motor 2. Brushless DC Motor
Brushed DC motors are one of the simplest and easiest of all DC motors. A brushed DC motor, which is commutated internally, is an electric motor that is operated from a direct current power supply. It uses an electric brush to deliver current to the motor windings by mechanical commutation.
The idea for the first electric motor was sparked by something as simple as a magnet. Although there were a few individuals experimenting with similar inventions we really owe gratitude to Thomas Davenport for the brushless electric motor as we know it today.
Davenport—an ordinary blacksmith—saw Joseph Henry’s electromagnet in New York in the early 1830s. He was so sure it could do more than being a spectacle (as it was at that point) that he sold a horse to raise the capital and purchase his own.
By taking it apart and studying it he realized the possibilities. He used four magnets and discovered the value of a brush & commutator switching device. With this he made his device do a full rotation when switched on, thanks to the interaction between the magnets. And so the electric motor was born.
In 1837 his electrical motor was officially patented but it took years for industries to realize its potential.
When DC voltage is applied through the brushes of a brushed DC Motor, electric current is passed to the windings of the rotor. The electric current excites the rotor coils and creates magnetic poles, and causes the windings of the rotors to act like a magnet.
When the rotor starts spinning, it moves into a situation where the commutator and brushes are no longer in contact with each other. So, no current flows into the coil. Though, original momentum makes the rotor remain rotating which causes brushes and commutator stay in contact. Thus, current is regenerated to the system and enables the motor shaft rotating.
For those delving deeper into the mechanics, brushed motors operate based on advanced electromagnetic principles. The interaction between the stator’s magnetic field and the armature windings results in torque generation. Mathematical models, including equations and algorithms, are used to optimize and control motor performance, ensuring efficiency and precision in various applications.
A brushed DC motor has two important parts, such as stator and rotor. Stator is the stationary portion of the motor and the rotor is the rotating portion of the motor. The rotor usually highlights coils around an iron core and enclosed by magnets located in the stator.
In a brushed motor, commutators are located around the shaft and connected with each other at every 120°. Commutators do not make mutual contact with each other. Commutators revolve together with the spin of the shaft. Every commutator is joined to a part of one coil and another part of another coil.
In it, two brushes are stable at 0° and 180° positions so that those can make connection with the commutators. The brushes are joined to a DC power supply and current flows through the direction like brush to commutator, then commutator to coil and then coil to brush.
The outside view of a brushed motor is displayed below:
1) Permanent Magnet Types: Permanent magnet brush DC motor is the most favorite among all brushed DC motors. This applies stable magnet to generate the magnetic field in the stator. This magnetic field is needed to operate the motor. The response to the change of input voltage of this motor is quite good. The speed of motor is easily controllable.
2) Shunt-wound Types: The shunt-wound brushed DC motor is made with the parallel connection between field coil and the rotor. Thus, stable torque at less speed can be easily generated by using this motor. This kind of motor is perfect in industrial and automotive uses with rigid speed control conditions.
3) Series-wound Types: The shunt-wound brush DC motor is made with the series connection between field coil and the rotor. The electric current in the stator and rotor is gained under load condition which makes them perfect for high-torque uses such as cranes and winches.
The speed of the brushed motor can be expressed through the following equation:
N = The speed of the brushed motor
E = The value of EMF
A = Number of parallel path
P = Number of poles
j = Magnetic flux (Wb)
Z = Total number of conductors in the armature.
| Advantages | Disadvantages |
|---|---|
| Construction expense is little | Frequent maintenance is necessary |
| Controller is easy and affordable | Less effective |
| Excellent for tough operating environments | High electrical noise |
| The life-time of DC Motor can be easily rebuilt | High rotor inertia |
| Simple and compact design | Less speed |
In the realm of continuous innovation, brushed motors are witnessing advancements in materials, design, and control systems. The integration of AI and machine learning is paving the way for smart motors that are self-optimizing, efficient, and adaptable to a range of applications.
Brushed DC motors are fundamental electric motors operated by direct current. They feature a straightforward construction with a stationary stator and a rotating rotor. The commutation process, facilitated by brushes and commutators, enables current flow and generates motion. These motors find extensive application in household appliances, automotive systems, and industrial machinery. While cost-effective and robust, they do require regular maintenance and exhibit certain limitations in efficiency and speed control. Overall, brushed DC motors remain a vital component in various industries, showcasing their enduring relevance in today’s technologically driven world.
Consider factors like required torque, speed, power supply, and application-specific requirements. Each motor type offers distinct advantages tailored for different scenarios.
Let us help you find a suitable brushed DC motor for your project.
Regular inspection, timely replacement of brushes, ensuring proper lubrication, and monitoring performance metrics are key to maintaining motor health.
With advancements in IoT and AI, brushed DC motors are becoming integral components of intelligent systems, offering real-time monitoring, predictive maintenance, and enhanced efficiency.
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