Research & Development

5 Reasons for the Brushless Motor Revolution

In these modern times, brushed motors found in conventional devices are becoming a bit of an anachronism. What used to be in every device, such as power tools (drills, hammers and saws), fridges, cooling fans, computer hard drives and electric vehicles, has been replaced by something more modern called brushless motors. This has allowed manufacturers to produce and consumers to enjoy what is known as modern electric devices.

Over the years, modern electric motors, also known as brushless motors, have increased in popularity. Today, you will find them in a lot of electronic devices, such as cordless power tools, that are used in a variety of home and industrial applications. It seems that many manufacturers of electronic devices are jumping on the brushless motor bandwagon. So, what is a brushless motor, and what advantages does it offer?

To understand what a brushless motor is, we have to take a brief look at what they evolved from, which is brushed motors. Basically, a brushed motor contains carbon brushes that transfer current coming from a power source (battery or power outlet) to commutator contacts located on the motor’s shaft. Now, the shaft contains a spinning armature/rotor inside of it and two permanently installed magnets on the outside. When the electric current reaches the armature, the electromagnet inside of it generates a magnetic field that repels the magnets, causing the motor to spin.

As the motor spins, so do the commutator contacts, and the brushes come in constant contact with them as they spin. This leads to a number of undesirable outcomes. For one, it means that the brushes will eventually wear out. Secondly, this produces a lot of electrical noise and sparks. Thirdly, the sparks cause some energy to dissipate. Since there are no brushes in brushless mortars, they are much more efficient. For one, there is no wearing of brushes to worry about, meaning brushless motors last longer. Secondly, the noise and sparks are significantly reduced. Thirdly, fewer sparks mean less energy dissipation, meaning brushless mortars require less power than their brushed counterparts to spin.

A brushless motor removes the carbon brushes and the commutator contacts from this setup. At this point, you might be asking yourself how power even reaches the armature when there are no brushes and commutator contacts to facilitate the transfer of current. Well, that is where some sort of circuit board is used to control the power that is supplied to the armature. The power is controlled using sensors located on the circuit board. For this setup to work, the armature is moved to the outside of the shaft while the magnets are placed on the inside. The removal of the brushes and commutator contacts coupled with the addition of a circuit board is where the advantages of the brushless motor lie.

Affordable

Perhaps this is one area where brushed motors have a slight advantage – the fact that they cost less. Because of their control circuitry, brushless motors have a higher initial cost, which they more than make up for in efficiency and durability (no brushes to wear down).

As you can see, brushless motors have ushered in a new generation of modern electric devices that are compact in size and offer better performance. Compared to conventional devices with brushed motors, the praise modern electric devices are getting is well deserved, despite the fact that they cost more. Modern electric devices are taking over, and many manufactures, as well as consumers, have wised up to their benefits and are not looking back.

Smart

The circuitry in the brushless motors that control the current makes brushless motors “smart.” Regardless of what you are doing, brushed motors will transfer the same amount of current to the motor all the time (unless there is some switch that you can use to manually control this). Brushless motors, on the other hand, have circuitry that can detect how much current the motor needs depending on the task you are doing at the moment.

Perhaps an example will best illustrate how this is a huge advantage. Suppose you are in the process of drilling some wood. Depending on how thick the wood is, a brushless motor will detect how much current should be transferred to the motor based on how much resistance the drill is facing. This has the advantage of making work more efficient. If the drill is cordless, less battery power will be used for the job compared to a brushed motor, which will use the same battery power no matter the job.

Now that you know the advantages of brushed motors, you can see that their popularity is well deserved. They are a drastic improvement over their brushed counterparts and that is what makes them a better alternative to brushed mortars. That is why many companies are using them in their electronics and many consumers are buying them.

Performs

When contrasted with brushed motors, brushless motors are smaller in size. This means they allow manufacturers to make compact devices without sacrificing speed and performance. This means an electric saw made from a brushed motor would be bigger in size compared to one made with a brushless motor. As you can imagine, a compact electric saw would be easier to handle and take less power (not to mention it would be much more powerful due to the brushless motor). Not only that, brushless motors allow manufacturers to produce mini versions of popular consumer gadgets as well.

Due to their brushless motors, modern electric devices are more efficient than conventional devices. Brushed motors require brushes, commutators and connections to deliver power to the rotor, the component on the motor shaft that causes the motor to spin, while brushless motors get their power delivered directly to the rotor using some type of control circuitry, eliminating the need for brushes.

The first boost in performance comes from the lack of brushes. Brushes are what deliver the current to the commutator contacts of the rotor. When this happens, some of the current is lost to heat. Since the power goes straight to the rotor in a brushless motor, no power is lost, making it more efficient than brushed motors. This also means it takes less juice to power a modern electric device compared to a conventional device.

The control circuitry found on brushless motors gives modern electric devices the ability to automatically control speed/torque. This is thanks to the sensors that are located on the control circuit, allowing it to detect the amount of stress the electric device is going through. If it is under a lot of stress, the motor will spin furiously, and when there is less stress, the motor of the modern electric will spin less.

Versatile

The global market for brushless direct current motors (BLDC) is witnessing growth, accelerated by electric vehicle (EV) adoption, manufacturing robotics deployment, and modern household appliances. Among most valuable advantages of brushless motors, are their high performance, control-ability, and low maintenance cost. Since these motors do not depend on brushed contacts, they are dust-proof and mostly require no maintenance for multiple years of operation. Moreover, popular manufacturing uses such motion control and positioning system also involve these motors.

Today most of the electric motors adapted in EVs are brushless DC motors. Compared to the conventional brushed motors with average efficiency under 80%, brushless motors can reach up to 90% efficiency with a good design. Meanwhile, they are safer since sparking caused by dust within brushes can be avoided, thus reducing risks of catching fire and system failure. Brushless motors are most common among smaller vehicles such as electric bikes, electric motorcycles. Light-weight motors enable consumers to easily move or carry their vehicles around. Moreover, brushless motors are deployed in hybrid electric and plug-in hybrid vehicles depending on their use. Advanced vehicle features may include adjustable mirrors, automotive sunroofs, etc. Power motors for these feature sets are now gradually changed from brushed ones to brushless.

Medical applications favour a brushless motor for its quietness, safety, and high control-ability. For instance, a blower fan used to treat sleep apnoea (temporary cessation of breathing while sleeping) needs to adjust its speed in accordance with a patient’s condition. In this case, a brushless motor can function smoothly at different speeds without minimum threshold, and with explicit low noise. Good robotic service and robot design require precision and faster responding time, and that is why BLDC motors can out-stand their counterparts. Brushless motor mechanism enable itself to fast reach a higher peak current, therefore providing a better performance in versatile operations.

Brushless motors can also offer reliable service when going high up to the space—utilised to power an oxygen transferring system on NASA aerospace; and too deep in the ocean—underwater drones. These are all owing to the technology’s excellent resistant performance under extreme environmental conditions. Brushless motors bring such advantages to manufacturers, industrial segments and consumers, while the higher expenditures make it seem less appealing, market price of some permanent magnet materials continuously experienced a downward fluctuating trend.

Clean

The debate over burning fossil fuels is something that gets more heated every year. The main source of contestation is that this type of fuel is non-renewable, meaning one day we will eventually run out. But with so many devices using an internal combustion engine (combustion engine), which need fossil fuels to run, is there an alternative that uses a renewable source of energy? The answer is yes.

The brushless motor is gaining popularity as an alternative to the combustion engine. The main selling point is that they use a renewable source of energy: electricity. While combustion engines burn up fossil fuels to create heat, which they then use to make mechanical energy, brushless motors use electricity to the same effect. Other than that, can we also say they are better in other areas than combustion engines?

Brushless motors are more practical compared to combustion engines which have a lot of moving parts, usually hundreds of parts, and they require supporting systems, such as a cooling system (radiator), lubrication system and gear transmission system. This means manufacturing them is complicated and hard. On the other hand, brushless motors have a couple of moving parts and can operate with none of these supporting systems. This means a vehicle made from brushless motors (electric vehicles) are easier to manufacture.

Since brushless motors are less complex than combustion engines, maintaining them is much easier as well. Due to the sheer amount of moving parts in combustion engines, these devices are much more vulnerable to faults, hence they require more maintenance compared to brushless motors. This means electric vehicles are easier and cheaper to maintain.

Although refuelling of combustion engines’ tanks is usually much faster, since all one does is fill up the tank of the vehicle. However, these days, modern vehicles can travel up to 644 km (400 miles) on a full tank of gas. This is significantly better than electric cars, which have been known to go up to 322 km (200 miles) before they need to be recharged.

Brushless motors are also much better for the environment than combustion engines since the cause less pollution. This makes them better for companies that are trying to spearhead the green initiative. In fact, brushless motors account for 15 percent of the pollution because lithium-ion batteries are not being disposed of properly. On the other hand, the emission of greenhouse gasses from vehicles is responsible for 50-90 percent of air pollution in urban areas.

Due to the internal combustion taking place and the firing of the cylinder’s pistons, combustion engine’s produce a lot of noise. This is the sound of hundreds of mechanical parts rubbing against each other. With brushless motors, the highest noise that can be heard is the whining sound that the pulse width modulation (PWM) driver, located on the control circuitry of the motor, makes as it switches frequencies.

While each device has its advantages and disadvantages, brushless motors are the future while internal combustion engines will become less sustainable in the long run as we deplete fossils fuels. This is a big point to consider for companies still manufacturing devices that use combustion engines. Rather than concentrate on a dying technology, it is better to switch to brushless motors and work towards making them more efficient.

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