In your search for the right drill, you may have run across the fact that there are two basic types of drill motors, brushed and brushless. Brushed drill motors are probably more familiar given their sheer numbers, but brushless drill motors are on the rise in terms of popularity.
Is Brushless Drill Better than a Brushed Drill?
In many circumstances, the answer is yes. A brushless drill is more efficient and the motor does not generate friction, so it will not heat up nearly as much as its brushed counterparts. Brushless drills are also energy efficient and require low maintenance.
So what is the difference between the two?
On the surface, it may seem that there is relatively little difference between the two. However, for those who will be using their drills frequently, such as for construction work, the differences are such that it does make a difference in which one you choose.
It pays to understand the mechanics of a brushless motor, what are the advantages, where is it lacking, and how does it stack up against its brushed counterpart?
What is a Brushless Motor?
As the name suggests the carbon brushes of traditional electric motors are absent in a brushless motor. In a brushless DC motor (BLDC) the coil windings are on the fixed part (stator) and the permanent magnets are fixed on the rotating shaft (rotor).
Although their rise in popularity is relatively recent, brushless motors have actually been around for more than 50 years. Invented by P.H. Trickey and T.G. Wilson in 1962 the brushless motor has undergone a number of improvements since its initial design, most notably the inclusion of a rheostat for controlling the speed of the rotating shaft.
* On a side note, the initial concept of the brushed motor was invented by Ernst Werner von Siemens way back in 1856.
However, it was not until the 1980s that the brushless motor began to take off. New technology, such as the inclusion of the power dimmer that allowed for the conversion of AC to DC helped to bring them into prominence. Twenty years later, the arrival of high-voltage transmitters with more permanent magnets available helped to push the brushless drill motor into the mainstream.
Makita is the first industrial tools manufacturer to introduce brushless motors into power tools.
How does it work?
A brushless motor works through a controller that transforms the DC current into a 3-phase variable frequency current so that the motor coils can generate a rotating field. A fixed stator holds the coils along with the mobile rotor where the permanent magnets are attached. With such an arrangement, the internal motor can generate up to 100,000 rpm.
Brushless motors are significantly more complicated than brushed drill motors. Plus, they have complications that result from their unique design. The greater the number of rotor poles in a brushless motor, the better the torque will be. However, this will reduce the overall speed which means it takes longer to complete a task.
In addition, there are three control algorithms that may be used to operate a brushless motor;
- Field-Oriented or Vector
- Sinusoidal Commutation
- Trapezoidal Commutation
The control algorithm used will rely on a combination of hardware, which is the circuitry, and the control software, which is the program used to operate the brushless drill motor. Each algorithm has its advantages and disadvantages, but they all work off the same basic principle.
Advantages of Brushless Drills
There are numerous benefits to using a brushless drill motor, starting with its unique design that creates greater longevity compared to its brushed motor counterpart. In addition, the other benefits have helped make the brushless drill motor quite popular around the world.
Brushless motors are smaller than their brushed counterparts, making it a more compact unit that weighs less while not sacrificing power.
Fewer Breakdowns (Longer Life)
Because the brushless motor has no brushes, there are fewer things to wear down and break apart. In addition, the lack of friction means less overheating which extends the life of the drill motor.
Adjust Power Supply
While brushed motors use the same amount of electricity no matter the task, a brushless motor can be adjusted based on your power needs. The sensor in the motor will automatically adjust the power requirements based on the resistance of the material. This makes brushless motors perfect for cordless use since it can extend the life of the battery.
Brushless motors also produce significantly less noise pollution when compared to the brushed counterpart.
There is a greater emphasis on the use of brushless drill motors thanks to their advantages. This means that more types and sizes are available for all kinds of jobs. Whether you need a drill occasionally around the house or every day at work, the brushless drill motor provides definite advantages for your needs.
The major disadvantage of brushless motors is the cost. Because they operate under a different principle compared to brushed motors, they tend to cost more. This is due to the sensors and sophisticated electronic circuitry needed to operate the motor.
However, this disadvantage is transitory as the drill itself will last longer which makes it a better long-term purchase for those who use them regularly.
If you only occasionally use drills for low to medium work, then a brushed motor may make more sense financially. However, even occasional use might work to the benefit of a brushless design because it is less prone to overheating. You may pay more, but you get quite a bit more in terms of overall benefits when you use a brushless motor design.
Brushless vs. Brushed Comparison
Although seemingly similar on the surface, there are a few significant differences between the brushless and brushed motors.
|Brushed Motors||BRUSHLESS Drill|
|Working Principle||Fixed magnets outside and copper coils on rotor.||Permeant magnets on rotor and copper windings on stator.|
|Design||Simple construction||Requires electronic circuits to control current|
|Unique Feature||Carbon brushes and commutator||The absence of carbon brushes|
|Speed Range||Lower speed due to design limitation.||Higher speed due to absence of brushes.|
|Battery Life||Normal||Efficient use of battery|
|Tool Life||May require periodic maintenance.||Longer tool life|
The direction of the electricity is reversed twice per cycle with the help of this rotating switch. This will create an electromagnetic field that is opposite to the permanent magnet outside creating a repulsive force that will rotate the shaft.
On the contrary, in a brushless motor, the rotor has the magnets and the copper windings are on the outside and hence there is no need for carbon brushes or commutator.
Now let’s examine these differences in detail.
Carbon Brush: Arguably the main difference is that brushed motors make use of spring-loaded carbon brushes which needs to maintain contact with the commutator.
On the other hand, brushless drill motor has no carbon brushes and incorporate magnets on the rotor to help them generate power.
Less Heat and Noise: Since there is no brush and commutator friction, the brushless drill generates very less heat.
Less Maintenance: Because there are no brushes, it is easier to maintain brushless motors. Not having to replace worn brushes means less work needs to be done to keep the brushless drill motors in top shape.
In addition to that, since the armature coils are on the stator the brushless motor requires no airflow inside to cool the windings. This means that the motor can be enclosed in a sealed casing that will eliminate dirt and foreign particles entering inside.
Fixed Coils: In brushless design, the alternating electromagnetic field created by the winding is not mechanical but instead driven electronically by a controller. This means that the coils are fixed to the motor and do not rotate as you would find in brushed motors.
Battery Life: The battery of cordless brushless drills lasts longer than regular drills. This is achieved through the use of electronic circuit that can detect the load on the motor and vary the current intelligently.
Here is how it works:
When you drive a screw into softwood or drywall the drills requires very less torque. So the electronic circuit supplies less current to the motor.
The moment the drill faces resistance the sensors prompt the electronic circuit to pass more electricity to produce higher torque. This is the reason brushless motors are also called as smart motors.
Should I get a Brushless Drill?
Yes, if you can afford one. Overall, they perform better than brushed units and can be adapted to different circumstances, unlike brushed drill motors. Brushless drills generate less heat and last longer.
Their compact nature means that they generally weigh less and are more ergonomically designed. However, if they are cordless, then the battery will definitely add some weight.
So, if you are looking for a better drill that provides plenty of speed while not overheating, a brushless drill motor provides the answer. They are also more compact and often weigh less and last longer because they lack brushes.