The Most Popular Motor Among Power Tools
It was nearly 1960s when the first brushless motor came out in market. In the recent 2003 we found them in industrial machines and finally around 2009 they were firstly used in power tools. Brushless motors were an improved form of the normal DC brushed motors, but more efficient and reliable. It is very important to know your machine’s motor type. Either you are a user, which is important to know how to take care of the machine and the maintenance information, or you are a buyer and don’t know the difference. In this article we will go through the cons and pros of brushed and brushless DC motors in power tools.
What Is a Brushless Motor?
A brushless DC motor (BLDC) is a type of motor without the brushes and commutator (explained further), that makes them lighter and more durable in high torques. You can find brushless motor not only in handheld power tools but also in vehicles.
The motor is made from a rotor (the moving component) and a stator (the stationary part), just like brushed DC motors, but with small differences. To get to know a BLDC motor better, you should first know the structure of a brushed motor.
Brushed DC motor structure
As you can see in the image below, a brushed DC motor has the stator and the rotor as well, but with additional components like brushed and commutator. As you can see, the armature (a coil) is connected to a DC power source through a pair of carbon brushes and commutator rings. Then the current will make a magnetic field in the coil, making it rotate in the presence of the other magnetic field, the electromagnetic coil around it (stator).
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How Brushless motor works?
In brushless motor, stator is a made from multiple permanent magnets. The stator yet is made up from winding coils which work as electromagnets. When the DC current flows in the coils and energizes them, the opposite pole of the electromagnet and permanent magnet attracts each other. To make it more efficient, the coil behind attracted coil can be energized too in a way that the electromagnet and the rare permanent magnet repel each other, so that the rotor get pushed even further. How is this possible? In order to make this process happening, the attracted coil and the repelled coil must have the same polarity current. Therefore, the are connected with a wire, working as a series circuit. But how can we control the energizing process of each pair of coils? This responsibility is given to an electronic controller, which is coded on how to energize each coil on specific timing and position. This controller usually gets the current position of the rotor from a Hall sensor, attached to the rotor.
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Pros and Cons
Advantages of Brushless DC motors
- Lighter in weight and more compact in size: The lack of brushes and commutator has made this type of motor more lightweight. Therefore, this feature has made the further power tools to be lighter too, which is a great profit for power tool’s manufacturers.
- Less noise: The contact between commutators and carbon brushes generates a continuous noise in brushed motors. This feature also makes a more pleasant experience for heavy-duty users.
- More powerful: The absence of commutator and brushes gives more room to add bigger winding coils. The bigger the motor, the more powerful they become.
- Minimum maintenance: The brushes will be worn out after long time of use due to constant contact with power terminal, as the commutator rapidly rotates. This problem will make the brushed motor useless and then it requires parts replacement. Since there is no contact between rotor and stator in brushless motors, there is no wear and tear consequently.
- Longer lifespan: The magnetic fields in brushless motor, does all the rotation force and there is no carbon brushes and other components to produce friction and heat. These two elements can lead the motor to a sooner breakdown. The wear and tear of brushed motor is unavoidable, even if brushes and components of best quality is used.
Disadvantages of brushed DC motors
- Costs more: The overall construction of brushless motors costs more. Hence, the power tools equipped with brushless motors have much higher prices. Additionally, the electronic controller (in form of ESCs) drives the price even higher.
- Complex structure: As mentioned above, the wiring of brushless motors is quite complex. Therefore, you can not often rebuild them to extend lifetime, such as sensor replacement of ESC installation.
Advantages and disadvantages of brushed DC motors
Basically, each pros and cons of brushless motor can sequentially be considered as advantages and disadvantage of brushed drones. But another points to mention: they are still ideal for extreme operating environment and heavy-duty tasks. You can also fix them more easily, by replacing the broken brushes simply with new ones. Above all, power tools with normal DC motors have reasonable price than brushless motors.
Brushless motors in power tools
When you open up a power tool, such as one the Ronix 89 Series, you will find a three-phase brushless motor with stationary windings. The motor driver circuitry is fully potted to protect the motor from moisture and dusts. The rotor is equipped with powerful compact neodymium magnets, two ball bearings and almost no grease on the spiral bevel gear.
There is no doubt that every user wants his/her tool to work for a lifetime. But every power tool has a specific lifespan, one day you should eventually replace them with a new one. However, buying a brushless power tool can guarantee durability, reliability and much more.
The Ronix new cordless tools, The Lasing Series, are all equipped with high quality brushless motors that ensures a powerful, secure and enjoyable work, whether drilling in concrete or cutting fresh grasses. Every motor in these cordless tools is powered by a single 20V battery, which is compatible with every other tools in its class.