By Grainger Editorial Staff 9/28/22
When it comes to power tools, how a tool is engineered can make a big difference in power and longevity. While brushless DC motors are relatively new to power tools, the technology has been around for decades. Brushless DC motors first came to market in the 1960s, helping power conveyor belts. In 2003, they began to be used in industrial machines and were first used in power tools around 2009. Brushless motors greatly improved the functionality of traditional brushed motors. While both motors work by converting electricity into mechanical force, brushed and brushless motors have unique differences in performance, cost, and maintenance.
To understand how brushless motors work, it helps first to explain how brushed motors work since they have been used in various applications from the late 1800s until brushless technology emerged.
Brushed motors contain four basic parts:
Stator: A stationary part of the motor containing permanent magnets that enable the rotor to move.
Rotor: A rotating part of the motor, also known as the armature, containing a copper coil that becomes electromagnetic when powered.
Commutator: A metal ring that helps the rotor keep spinning by reversing the polarity with every half turn of the rotor.
Brushes: Made of carbon and directly connected to the power source, helping relay power to the commutator ring and activate the rotor.
The carbon brushes create a lot of friction by spinning and making constant contact with the commutator, and there lies the major distinction between that traditional type of motor and the newer brushless motor technology.
Brushless motors, in comparison, contain a stator, armature and rotor but have no physical commutator or brushes. Instead, tools with brushless motors rely on magnets and an electronic circuit to connect the stator and rotor and create power. This design eliminates the friction present in a brushed motor, leading to several advantages, including:
Brushless motors are sometimes called smart motors because they contain computer chips and internal sensors that adjust their speed, torque and power supply depending on the application. For example, when using a brushless tool to drive a nail into drywall compared to a denser material, a brushless motor’s electronic circuitry allows it to use only the necessary amount of power needed to complete the job.
Excessive heat can wear down motors and batteries. Brushless tools run cooler than brushed tools since the winding mechanism that often generates heat is located on the casing of the tool instead of the inside. There is less friction, and hence less heat.
Brushless power tools last longer than brushed tools because there aren’t any brushes to replace. Brushed power tools often require replacement brushes every two to seven years because the friction causes the brushes to wear down quickly, depending on the working environment and operating temperatures.
Brushless tools also can enjoy better protection from dirt and debris because they don't need air vents for cooling, thanks to lower heat generation.
Without brushes and commutators in the motor, brushless tools are often lighter and more compact, allowing users to get into tighter spaces. Less friction and vibration allow brushless motor tools to operate more quietly and comfortably for longer periods of time. Brushed motors can also generate sparks during use; therefore, brushless motors are often preferred in hazardous conditions.
According to Consumer Reports, brushless motors are more energy-efficient than brushed, often running on battery power for up to 50 percent longer. Since brushless motors don’t contain brushes that lose energy to friction, they have a longer battery life than brushed tools. Many models can run for hours.
Brushless power tools are typically 30% more expensive than brushed ones, thanks to the complex electrical systems inside the stator. Whether a brushless tool is right for you ultimately comes down to usage. Brushed power tools are lower cost and run at a constant speed, making them a good choice for lighter projects. However, if you are a professional using the tool regularly or for heavy-duty jobs, a brushless tool might offer more efficiency, speed and tool life.
The information contained in this article is intended for general information purposes only and is based on information available as of the initial date of publication. No representation is made that the information or references are complete or remain current. This article is not a substitute for review of current applicable government regulations, industry standards, or other standards specific to your business and/or activities and should not be construed as legal advice or opinion. Readers with specific questions should refer to the applicable standards or consult with an attorney.