The power tool market is saturated with different kinds of drills. But when it comes to motors they fit into two categories: brushed vs brushless motors.
If you’re looking for a new power tool, you’re likely weighing up the benefits of a brushless vs. brushed drill. Well that’s what I’ll cover in this article.
I’ll go over the differences between brushed and brushless drills, and how this influences their performance and cost. I’ll also cover a range of FAQs that often pop up.
Hopefully by the end of this article you’ll have all the information you need to make an informed decision about which type of drill will be best for your toolkit.
Brushed Drill Motors
The brushed drill motor is the original drill motor design. When the portable electric drill was invented in 1916, it featured a brushed motor setup.
The fact that it’s still going strong as a popular design is a testament to its functionality.
How They Work
All drill motors convert electrical energy into mechanical energy, specifically rotational energy. It transfers this energy through a motor shaft, spinning the drill chuck and drill bit.
A brushed motor has 4 main components: permanent magnets – known as the stator, commutator, armature, and brushes. The armature are of copper wire wound around an iron core – that become electromagnets when a current flows through them.
Like all DC motors, brushed motors use magnetism to convert electricity into rotational motion. The stator magnets, maintain a constant electromagnetic field. While a set of electromagnets that make up the armature have their electromagnetic fields reversed at least twice per revolution.
The constant push and pull between the magnets and electromagnets is what causes the motor to rotate. The permanent magnets attract the electromagnets as they’re traveling towards them and repel as they travel away. This has the effect of causing the armature to rotate within the stator.
But the difficulty in creating this kind of motor is how to constantly reverse the current flow on the electromagnets. This is where the brushes and commutator come in.
Usually made from carbon filaments, these brushes deliver an electric current to the armature via the commutator. One of the brushes will be connected to the positive side of the power source and the other brush is connected to the negative side.
The commutator is a split ring with each side connected to a coil on the armature. The commutator rotates with the armature therefore reversing the current flow as each of the positively and negatively charged brushes come into contact with it.
While it might sound a bit confusing, the main bit of information you need to know is that the brushes help to reverse the armature’s polarity. In turn, this causes the motor to spin.
Brushless Drill Motors
The brushless motor was invented in the 1960s thanks to advances in solid state commutation technology.
Thanks to these advances, brushless motors were able to address many of the pitfalls of brushed motors. They quickly became a popular option because of this.
How They Work
The most obvious point to make about a brushless motor’s mechanics is that it doesn’t contain brushes.
In a brushless motor, the position of the fixed magnets and electromagnets are basically reversed. It locates the permanent magnets on the rotor and electromagnets on the stator (the outside of the motor).
This means you no longer need brushes and a commutator to reverse the electromagnetic fields. Instead the direction of the magnetic fields are controlled by a electronic controller circuit board. A sensor constantly monitors the position of the rotor and energises the coils when required to keep the motor spinning.
As you can imagine, this makes the mechanics a fair bit simpler.
There are 3 main types of brushless motor setup:
- Trapezoidal commutation.
- Sinusoidal switching.
- Field-oriented control.
We don’t really need to go into the specifics of what these mean. Simply put, they offer different ways to control torque and speed through varying the electromagnetic state of the motor.
If you are keen to learn more you can check out this video on how brushless motors work for more technical information.
Brushless vs Brushed Motors
Size and Weight
Brushed motors don’t really have an impact on the drill’s size and weight. You’ll find brushed motor drills for all applications, ranging from occasional wood drilling to heavy-duty concrete drilling.
The limiting factor on the size of an electric motor is often to do with the heat dissipation. For a brushed motor the heat is generated in the copper coils which are in the armature. Dissipating this heat is therefore difficult compared to a brushless motor where the copper coils are positioned in the stator on the externals of the motor.
The friction created by the brushes making contact with the commutator and contact arcing add further to the heating of brushed motors. All this combined it’s easy to see why smaller brushless motors can be made compared to brushed versions.
The ability to make brushless motors smaller, and with the removal of the brushes and commutator it easy to see how brushless motors can be much lighter too.
Power, Speed and Torque
Brushed DC motors are a well established technology and can be designed with a range of power outputs.
Power is the product of speed and torque. So for a fixed power, if you increase the speed you lose torque and if you want to increase torque you’ll have to lower the speed. If you want to increase both….. you’re going to need more power.
So the question isn’t are brushed motors more or less powerful than their brushless counter parts, because you can make them as powerful as you want.
What we have to consider here is power to size ratio. And as we’ve already discussed, as brushless motors can be made smaller than brushed models, the power to size ratio is generally higher.
It is also the case that due to the electronic control of brushless motors they can better control the delivery power when you need it. For example, in order to maintain a constant speed, they can deliver more torque and therefore power when required.
You can probably already guess the answer to this. When it comes to the energy efficiency of brushless vs. brushed drills, brushless comes out on top.
Brushed drills have a lot of friction to deal with, which converts the mechanical energy into heat. As a result, they’re less energy efficient because heat is a waste product.
Again as mentioned above, the advantage of having electronic control over the power delivery means that the optimum power can be delivered. So if low speed and low torque are required, a lower amount of power can be delivered to the motor.
One advantage brushed drills have over brushless is cost. Brushed drills are generally much cheaper than brushless because the technology is simpler.
You can get a pretty basic entry-level brushed drill for almost nothing. But if you want a decent drill with variable torque and speed, you’ll obviously need to pay a bit more.
This makes brushed drills a good choice for those who won’t be using it often, as it won’t take much to justify the price tag. Similarly, it makes them a good choice for those new to DIY.
But one added cost to brushed drills is that you need to replace the brushes after roughly 60 hours of use. While this is an added cost, the brushes don’t cost much at all.
Plus they’re pretty easy to replace, so don’t be put off by this. In fact, you can check out this video on how to change drill brushes for all the information you need.
Pros and Cons of Brushed Drills
You might think that there’s no reason to opt for a brushed drill over a brushless, but this isn’t always the case.
Consider these pros and cons to see whether a brushed drill would still be a good choice for you.
- Inexpensive – you can pick one up for next to nothing.
- A good choice for beginners or infrequent users.
- Brushes are inexpensive and easy to replace.
- Easy to maintain – can be done when changing the brushes.
- Less efficient than brushless drills – you lose energy as heat.
- Brushes need replacing after 60 or so hours of use.
- Dust can get trapped in the motor and cause it to wear faster.
- Loses torque as it speeds up and as brushes wear down.
Pros and Cons of Brushless Drills
Much like brushed drills, it’s worth weighing up the pros and cons of brushless drills before deciding whether they’re the right choice for you.
They might sound like the better choice, but they do have some disadvantages that are worth considering.
- Much more energy efficient.
- Longer lifespan.
- More reliable – no surprise brush changes needed.
- Providing you look after them, they’ll last forever.
- Lighter and more compact – better versatility.
- Pretty much maintenance free.
- More responsive – automatic power and torque adjustment.
- More expensive than brushed drills.
- Can be expensive to repair; you’re often better replacing.
Brushless vs. Brushed Drill FAQs
By now you’ve likely got most of the information you need to make the right decision about your next drill.
But just to solidify your choice, read through these FAQs as they should answer any final questions you might have.
Is a brushless drill worth it?
Brushless drills have a higher initial cost than brushed drills, but this is offset over the drill’s lifetime. They’re more energy efficient, more powerful, and have a more consistent torque output. Add this to their lighter weight and greater versatility, and brushless drills are definitely worth it.
What’s the difference between brushed and brushless?
The main difference between brushed and brushless is the motor’s construction. Brushed drills feature electromagnets on the rotor, and static carbon brushes running on a rotary switch called a commutator reverse their polarity. Brushless motors have electromagnets on the outside and the permanent magnets on the motor. Removing the need for brushes.
How long do brushless motors last?
Brushless motors can last almost forever providing they’re well built and well maintained. A brushless motor doesn’t suffer from friction between the brushes and the rotor. The life of a brushless motor is limited only by the bearings. It’s more likely that something else on the drill will break long before the brushless motor.
Are brushless motors faster than brushed?
Brushless motors are faster than brushed because they’re not limited by friction. As friction builds in a brushed motor, it reduces speed and efficiency. Brushless motors convert up to 90% of the electrical energy into rotational energy, and can do so at much greater speeds.
Why are brushless motors more expensive?
Brushless motors are more expensive because they contain more complicated parts than brushed motors. Solid state commutation technology is more advanced and more expensive to make, which bumps up the price. They can be more than double the cost of brushed drills, and typically cost around 30% more to make.
Are brushless motors quieter?
Brushless motors are quieter than brushed motors because they’re more efficient. Sound is a waste product in a motor’s function, and brushless motors are up to 90% efficient. But it’s not a significant difference, so don’t let this be a major buying factor.
Brushless vs. Brushed – So Which is Best?
When it comes to the all-important question, brushless vs. brushed – which is best, there isn’t a single answer.
In my opinion, brushless drills are better if you can afford the higher price tag. They’re more efficient, last longer, and have better power output than brushed drills.
Also, they’re better for compact jobs and make a great addition to both professional and at-home toolkits.
But they might be out of reach for many looking for a quick and easy drill. If this is you, go for a brushed drill because their price point is much lower.
If you’re thinking about buying yourself a new drill why not take a look at my power drill product reviews and buying guides?
Hopefully I’ve covered everything you need to make a decision about which type of drill is best for your needs.
Do you have any other information that would benefit others when making this decision?
If so, drop a comment below to share your knowledge!