The impact of Brushless motors on electric hand tools is reminiscent of the transformation following the 2005 introduction of the lithium-ion battery, which, at the time, was heralded as the most significant development in power tools over the previous 20 years. With the brushless motor, electric hand tools continue to evolve.


Toolmakers say brushless motors generate as much or more power than conventional motors, operate more efficiently, and are more durable.


Unlike conventional motors, a brushless motor uses an electronic switch rather than a mechanical one to commutate, or regulate direction of, the motor. Brushless design eliminates the brushes and commutator, and a circuit board coordinates the electronic energy within the motor.


A tool with a brushless motor often is classified as “smart” because an electronic signal communicates directly with the windings and adjusts power draw to the task at hand, rather than always operating at full speed. When the motor senses a lack of resistance, it draws less power, extending battery use per charge.


Brushless motors have been in use on large industrial motors for more than 50 years. In 2003, Makita developed a brushless impact driver for the defense and aerospace industries. In 2009, Makita brought that first brushless impact driver to the market, said Wayne Hart, communications manager, Makita USA.


Because there are no carbon brushes, the motor runs contact-free and without resistance, eliminating wear on the tool’s armature for longer tool life, Hart said. Contact-free operation also means cooler, more efficient operation. Unlike conventional motors, the brushless type does not require regular brush replacement, so the tool spends more time working, lasts longer, and has increased power and speed. Electronic control also optimizes battery energy use for up to 50 percent longer run time per charge.


Makita’s current lineup of 18V brushless tools includes drill drivers, hammer drivers/drills, impact drivers, rotary hammers, reciprocating saws, circular saws, metal cutting saws, drywall screw guns, impact wrenches, angle grinders, blowers, and string trimmers.


Hart said more Makita 18V brushless tools are on the way.


DeWalt offers brushless-motor-powered drill drivers, hammer drills, multitool, SDS Plus hammers, band saws, impact drivers, framing nailer, finish nailer, drywall screw gun, and impact wrenches.


Brushless motors provide four basic advantages, according to David Veprek, director of product marketing, DeWalt.


“The first advantage is higher efficiency, which provides longer run time and cooler running motors,” he said. “The second advantage is higher power density. By using brushless motors, you can deliver the same or higher power in a smaller platform. The third advantage is increased controls. Because brushless motors require electronics, you have the ability to add features like speed control or brakes to a tool. The last and perhaps most obvious thing is increased durability by eliminating brushes, which are a wear part.”


[SB]Veprek estimated that brushless motor tools make up about one-third of the market.


“Although brushless motors will eventually take over, I don’t think the business will ever fully transition to all brushless tools,” he said. “However, there isn’t a tool out there that won’t offer a brushless option in the future. Improvements in magnetic materials and manufacturing will continue to push the envelope and improve efficiencies in brushless motors.”


Bosch's lineup of brushless tools includes drill/drivers, hammer drills, impact drivers, impact wrenches, rotary hammers, an oscillating tool, a grinder and a planer.


“Brushless motors provide more efficient motor performance without arcing and longer life,” said Tim Truesdale, cordless product manager, Bosch. “Traditional power tool motors rely on carbon brushes that contact a commutator. The commutator periodically reverses current between the rotor and the external circuit. It includes a cylinder with metal contacts on the armature, so it’s mechanical.


“Contrast this with a brushless motor that offers greater torque efficiency, greater reliability because there’s no brush or commutator deterioration, and [it eliminates] sparking. In addition, a brushless motor can be cooled by conduction, so there’s no airflow requirement and less concern for dirt in the motor compartment,” he said.


According to Truesdale, the tool industry is moving toward brushless motors because they are more efficient and require less maintenance.


“Customers are demanding these products,” he said. “The current inhibitor to greater market share is higher cost and rare-earth-magnet component availability. The brushless platform allows for a much smaller and more compact dimension and should lead to better torque values. In the future, these tools will continue to provide higher torque levels and better efficiencies to help expand battery run times.”


He estimated that approximately 10 to 20 percent of power tools sold today are brushless.


“Prices will need to go lower for larger volumes to become effective,” he said. “But at some point, brushless motors will become the dominant product in 
zthe market simply because they are more efficient and last longer.”


Milwaukee Tools offers brushless motor tools: hammer drills, rotary hammers, band saws, circular saws, reciprocating saws and press tools.


“Currently, 40 out of the 90 products on our 18V lithium-ion line are brushless,” said Paul Fry, senior vice president of product management, Milwaukee Tool. “By removing the mechanical commutation system, the electronic commutation allows for more room to add more power-generating materials [copper, metal, magnets]. 


“The brushless motor design is inverse of a traditional motor. The copper windings are on the field/stator of the motor, and the magnets are on the armature. This is more efficient because it draws less current to do the same amount of work, and it doesn’t have the loss of efficiency from the mechanical commutation.”


According to Fry, two benefits come to mind: First, because the commutation is controlled electronically, not mechanically, it is a wear-free design, a system that has less efficiency loss and a much more durable motor. Second, performance advancements over conventional motors include run time, power and application speed.


However, best-in-class performance and run time cannot be achieved by simply putting a brushless motor in a tool.


“Tying brushless motors to the world’s most capable electronics packages and most advanced lithium-ion packs pushes the boundaries of cordless tool performance and truly allows the user to experience the productivity benefits a brushless motor has to offer. The complex interworking of lithium-ion, motor technologies and electronics is what makes tool products truly different from other brushless tools on the market,” Fry said.


He said brushless motors will continue to affect the tool market.


“There’s a variety of opportunities to use brushless motors in other tools and tool categories,” Fry said. “But it all comes down to what demands the user has. Based on usage and applications, there are times when brushless motors won’t necessarily add a significant 
benefit. It’s really about determining where brushless is necessary and critical to driving performance. 


At the end of the day, it’s really all about optimization.”