The two most common types of motors that are a part of machinery and electronic configurations are Brushed DC Motors and Brushless DC Motors (BLDC) and are widely used in the industrial sector. The principle working mechanism of both motors is the same, which is the conversion of electrical energy into mechanical motion. But their makeup and design configuration makes them different in major aspects like efficiency, torque delivery, durability, and maintenance. These differences are vital discussions for electrical engineers, product designers, or anyone involved with electric-powered systems.
This blog examines the differences between BLDC and brushed motors centered around three key topics: efficiency, torque characteristics, and maintenance requirements. After reading the blog, you will be able to determine which motor type is best suited for your application.
Brushed DC motors? These things have been a part of machine systems for a long time and your grandpa probably fixed one in his garage at some point. They run with brushes and a commutator (think of it as a rotating switch that keeps the juice flowing to the spiny bit inside called the (armature). As it whirls around, the brushes rub up against different parts of the commutator, so power keeps flowing, and the thing keeps turning. Super basic design, and that is why they are used in nearly every electrical or mechanical application. They crank out solid torque at low speeds—perfect for stuff like power tools, RC cars, or even cranking your car engine on a freezing morning.
Now, brushless DC motors (BLDC for short)—that’s a whole different machine. No brushes, no commutator. Instead, you get some slick electronics doing all the switching, so you don’t have to worry about brushes wearing out. The magnets are chilling on the rotor (the spinning part), and the windings just sit there, not moving at all. End result? These motors are smoother, quieter, and way more efficient. You’ll spot ‘em in drones zipping around the park, those fancy Teslas, HVAC units, and all sorts of modern machinery. Basically, if it feels high-tech, it’s probably running on a brushless motor.
Frankly speaking, BLDC motors tend to have better energy consumption by a large margin compared to brush motor. This is mainly because they do not have any brushes in their configuration, which eliminates friction and electrical losses. With the brush and commutator always in physical contact, some energy loss is always happening which leads to the motor heating up. The energy lost as heat also affects the overall performance of the motor and, wear and tear may result in an increase in maintenance cost.
BLDC motors show a high efficiency of 85 to 90%, and this factor alone means that they are generally the ideal choice for battery-operated devices. With their superior efficiency, they are able to work longer hours compared to brush motors.
An inevitable consequence that occurs due to the configuration of the brush motor is faster heating up due to friction. This translates to worse performance in the long run. Since BLDC motors have no moving parts, the heat dissipation is considerably less, and the temperature of the motor stays constant for a longer time. In demanding operational environments, this means that the BLDC motor does not heat up excessively.
Both motors output torque, which is the rotational force generated by the motor, and torque is the driving force behind numerous applications. The specialty of bush motors is that they can output considerable torque during startup. This quality makes them a suitable fit for applications that need a powerful turning force, such as actuators and electrical winches.
BLDC motors also deliver powerful torque but what gives them the upper edge over brush motors in this aspect is that they can sustain high torque at different speeds. The outcome is higher degree of precision and flexibility that delivers predictable movement in high-end applications like robotics. Since they don’t have moving brushes their torque output remains reliable over long term as the brushes tend to wear out due to friction.
BLDC also has greater design flexibility that can be utilized to integrate these motors in specific applications more easily than brush motors. They can be configured as inrunner or outrunner depending on the requirement, so the result is peak torque output. Moreover, advanced BLDC controllers can be added to introduce the function of dynamic torque adjustments that boost the BLDC motor performance to a whole new level and give it a precision that is suitable for electric vehicles and automated manufacturing lines. Something which is extremely difficult to accomplish for a brush motor.
A major downside of brush motor is their maintenance expense. With continuous operation, the brushes tend to wear out since they rub against the commutator. The inevitable result is more downtime as the brush replacement needs to be done frequently, and this downtime reflects badly on work productivity. Not to mention that the maintenance costs add up over time, and this can weigh on the budget. A side-effect that also affects operational performance is the formation of dust that occurs when brushes come in contact with the commutator and in a closed space, this can have a negative effect on nearby components.
BLDC motors do not suffer from the issue of brush wear and tear because they simply do not have one. With such a cutting-edge design, the operational life of a BLDC motor is considerably higher than that of a brush motor. The only real maintenance that a BLDC motor requires is bearing lubrication, and that is something that only occurs occasionally.
So, when we look at maintenance and performance, BLDC motors really do have a winning edge compared to brush motors, and that is why they are used in HVAC systems, medical devices, and electric transport where long usage life is preferred. For owners of BLDC, an added advantage is lower maintenance cost that results in more uptime of machinery, which is a win-win.
BLDC motors on the whole are much better alternative but they do have one drawback and that is their higher purchase cost. BLDC motors need an additional component to control their performance, which is the electronic controller, and this significantly increases the price of BLDC motors. The manufacturing cost of the BLDC motor is also high since it consists of motor control algorithms and electronic circuits that are absent in the brush motor. Brush motors, having a much simpler design, cost less and are also easier to configure.
The use of BLDC motors versus brushed motors depends on an array of factors like application, performance goals, and budgetary constraints. Brush motors are still appropriate for simple, inexpensive applications requiring high torque without complex controls. However, for applications requiring efficiency and longevity with low maintenance, a BLDC motor is a clear winner.
As industries transition to smarter and more sustainable solutions, the move to BLDC technology will accelerate. The fast-starting, low-noise home devices, or the demanding, positively-reliable electric vehicles and industrial machinery, have presented new applications for BLDC technology. The evolution of motion control continues with the value of brushed or BLDC motors. By knowing the clear differences between the motors, designers and engineers can appreciate the advantages and disadvantages of each type of motor and make the best decision and contribute to the performance and efficiency of their system.