Chances are, you’ve noticed all of the talk about “brushless motors” when it comes to hammer drills, cordless drills, etc.
These days, this seems to be the biggest thing to hit the power tool scene since cordless power tools.
So, what exactly makes a brushless motor better? What exactly is a brushed motor? Is there really any significant difference between the two, or is it simply a marketing gimmick?
Keep reading and soon, you’ll be an expert on the subject.
Brushed/Brushless Motors: What is the Difference?
First of all, the truth is that brushless motors are not a marketing gimmick. They work very differently than a brushed motor and there are quite a few advantages to a brushless motor. However, before we can get into that, we must figure out what exactly drives an electric motor to begin with.
Sure, you plug it into the source of power, but what is it that causes the motor to spin?
In both types of motors, magnets are what cause the rotary/spinning motion of the shaft of the motor.
Think about it, when you were a kid, did you ever try to push the N side of a magnet against the S side? Do you remember what happened? A force was created that caused the magnets to repel against one another. This is what drives an electric motor.
If you have a brushed motor, you must note that no matter whether your power tool is plugged directly into the outlet in your wall, or it is battery powered, the power supply will be run through two small carbon filament blocks, which are located on either side of the motor shaft.
These carbon filament brushes come into contact with a portion of the motor known as the commutator. This part is fixed onto the motor shaft. The commutator then transfers the current of electricity from the carbon brushes to the armature, also attached to the shaft of the motor.
Basically, the armature is a bunch of copper wire tightly wrapped into a dense coiled pattern. As the electric current passes over the copper coils, a field of electromagneticity is created. Then, on the external portion of the motor are a set of non-moving N and S magnets. As the armature is charged electromagnetically, the motor starts to spin due to the opposing forces of the magnets.
On the other hand, though they do use the same basic principle to operate, a brushless motor is a bit more complex than a brushed one. This is because in a brushed motor, the copper wiring is on the motor shaft and the magnets are fixed to the outside of the motor. In the case of a brushless motor, these components are opposite.
The magnets are on the rotor (that is, the part that spins) and the copper wiring/armature is fixed on the outside of the motor. You may be wondering where a brushless motor gets the power supply to create the electromagnetic fields if there are no carbon brushes. This is the whole reason why a brushless motor is trickier and costlier.
In order for the brushless motor to operate, it needs additional electric components. This is typically in the form of a small, expensive circuit board controlling the power to the copper wiring, as well as a sensor that discerns the motion of the rotor.
As the coils are supplied with an electric current from the circuit board, the electromagnetic field is then created, which causes the magnets to start spinning.
Advantages of Brushless vs. Brushed Motors
Now that you have a basic idea of how each motor works, lets take a closer look at the advantages of brushless motors and why it seems that everyone in the DIY industry has jumped on the bandwagon.
They last longer
Do you recall how we stated that in the case of a brushed motor, the brushes are constantly in contact with the rotating portion? As you may imagine, this results in tons of friction, which then results in heat/loss of energy, and therefore, wear and tear.
On the other hand, in the case of a brushless motor, there are no brushes, so the rotor is not in constant contact with anything. Therefore, there’s nothing to cause a loss of energy and wear and tear.
So, it stands to reason, a brushless motor is much more efficient and will last much longer than a brushed motor. In addition, due to the fact that there are no brushes to cause energy loss, a brushless motor is much more powerful- though it may be the same voltage as it’s brushed counterpart.
They have “smart” motors
In addition, perhaps you’ve heard some companies refer to a brushless tool as having a “smart” motor. They are talking about the electric sensors that are on the circuit board of their brushless motor.
In the case of a brushed motor, you always have the same level of electrical current flowing through the motor, regardless of what you’re doing. On the other hand, due to the fact that the circuit board is delivering the current to the armature, it can adjust flow of power depending upon what you are doing at the time.
For example, let’s say you need to do some light work, such as removing some screws from drywall. If you are using a brushless motor, it will determine that there’s not a whole lot of resistance against your rotor. Then, it will “talk” to the circuit board and tell it to slow down on the flow of power.
On the other hand, if you’re doing something harder, such as trying to drill through a 1/4-inch steel tube, the sensor determines there is more resistance and tells the circuit board that it needs more power.
Once again, you’ll find this results in a much more efficient tool and you won’t have as much battery drain on a brushless motor as you would a brushed one on the same project.
Disadvantages of Brushless vs. Brushed Motors
Of course, as with anything else out there, you’ll find that there is a disadvantage to a brushless motor: the cost. Due to the complexity of the circuitry, they do not come cheap.
If you are shopping for a new cordless power drill, you’ll see a major price difference between brushless vs. brushed. However, you must think about what you’ll be using it on and how often you’ll be using it.
Chances are, you’ll see that the price difference really is worth it, especially if you like to do home improvement projects yourself instead of calling in a pro.