You have probably noticed by now all this talk of “brushless motors” on hammer drills, cordless drills, and so on—it appears to be the biggest craze to hit the DIY/power tool market ever since cordless power tools themselves.
A motor converts supplied electrical power into mechanical power. Different types of motors are in common use, among which brushless motors feature the highest efficiency and controllability, and are extensively used in numerous applications.
Yes, brushed motors are cheaper compared to brushless motors, but it goes without saying that you’ll benefit more from the latter.
A brushless motor is a direct current (DC) electric motor which operates without the mechanical commutator and brushes of a traditional brushed motor. It offers distinct advantages over a brushed motor and is more efficient in the long run.
Often referred to as BLDC/BL motors, brushless motors are increasingly becoming popular among professional and DIY users. However, they aren’t new to the game.
To understand their origin, we must look back to Mr. Ernst Werner von Siemens’ inventions in 1856. The inventions, though rudimentary, have undergone several improvements over the years, one of which was a rheostat for regulating the shaft’s rotational speed.
Brushless motors’ journey to fame started in the early 60s with the invention of a power dimmer with the ability to convert alternating current to direct current, i.e. AC to DC.
In 1962, P. H. Trickey and T. G. Wilson published an article reporting a brushless motor working on DC. The units were implemented with a technology that used magnetism and consecutively opposed via an electric device. The key revelation behind the ”brushless motor” concept was the absence of a physical switch for transmitting the current.
That said, it wasn’t until the 80s that brushless motors actually got off to a promising start. The availability of permanent magnets in conjunction with high-voltage transistors enabled this type of motor to produce as much power as a brushed motor.
Brushless motors have since gone through many tweaks and improvements. They’ve changed and enhanced the way drill manufacturers develop efficient, cost-effective drilling tools. And in turn, consumers are reaping the following advantages associated with a brushless motor.
#1. Less maintenance
A brushed motor is known for having parts that tend to wear out after a certain period, requiring frequent parts replacement and dismantling.
The reason this occurs is that the commutator’s brushes need to keep regular contact with the power terminals, while the commutator rotates rapidly. As the brushes get worn out and fail to maintain contact, the brushed motor essentially becomes useless.
This is no longer an issue with the brushless motor. In fact, there’s basically no contact between the stator and rotor of a brushless motor. Therefore, wear and tear are reduced significantly.
#2. More efficient
As already mentioned, the regular contact of the brushes with the power source terminals is required for the brushed motor to maintain rotation. But the friction this creates indicates that a large portion of the energy produced by the rotational motion is dissipated as heat.
A brushed motor’s efficiency is usually limited within the range of 75 to 80 percent. On the contrary, a brushless motor generates remarkably less heat. There’s still some energy loss caused by air friction as the rotor rotates rapidly, but that is still minimal.
A brushless motor can offer up to 90 percent efficiency. There are a number of customization methods for a brushless motor that further improve its effectiveness, such as enhanced ESC algorithms, heat-resistant coils, stronger magnets, etc.
#3. Longer lifespan
The accelerated wear and tear owing to continuous contact of the brushes and the energy generated as heat indicates that a brushed motor is expected to cease functioning much sooner than a brushless motor. For example, even for a toy drone, it’s usually not recommended to run the brushed motor for longer than a few minutes constantly. With zero chance to cool down, the built-up heat in a brushed motor can potentially harm the integrity of its brushes or coils.
For drones that are designed to fly for longer periods, there’s no better option than using a brushless motor. Yes, there’s still some heat formation because of air friction, but this is retained at a low level. Generally, a brushless motor can operate from 30-60 minutes continuously without a hassle.
Brushless motors used in drones have a reputation for lasting several years with little to no maintenance, notwithstanding accidental crashes.
A brushless motor doesn’t have as many moving parts as a brushed motor, which gives it the advantage of boasting a more compact design. This is extremely crucial for modern drones that are ultra-portable and designed in a very small form factor.
Brushed drones generate a lot of noise, most of which is caused by the constant contact of the brushes with its power terminals. While using lubricants may seem like a good alternative, this is an issue that’s pretty much unavoidable when operating a brushed drone.
On the other hand, brushless drones are more on the quieter side. Now, you can argue all day about the “whirring” sound created by the rapid rotor rotation, but it’s still a vast improvement to the annoying, screeching sound generated by the brushed motor.
More recent advancements in ESC design have enabled brushless motors to rotate more smoothly, reducing the accelerated “stop and go” motion of the older technology.
We recommend brushless motors to those who are willing to spend their hard-earned money on a premium tool that will last them longer. As tool design enhances and battery technology advances, we’ll be seeing more brushless motors and tools at our local stores.
Brushless motors aren’t going anywhere, and it’s only a matter of time before this technology takes over the entire market.
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