Editor's Review: Brushless motors: The next big thing in cordless power tools?
review date: March 8, 2012
By the time you read this, your local tool supplier will likely be
stocking shelves with a new shipment of tools. These tools may have
marketing lingo about a new “e-motor,” “BL motor,” or something similar.
These terms refer to brushless motors.
To be fair, brushless
motors are not a new technology, and some manufacturers already offer
brushless tools, if only a limited selection. All signs now are pointing
toward a bigger push, though. Makita and Hitachi are expanding their
current offerings, Milwaukee and DeWalt are releasing their tools this
spring, Bosch is aiming for a date later in 2012, and other
manufacturers are undoubtedly working on their own updates.
manufacturers argue that brushless motors mean a reduction in
maintenance because, just like the brake pads on a car, brushes wear
out. How quickly the brushes wear out depends on how the tool is used.
to tests conducted by the company, Milwaukee’s brushed-motor drills
bored an average of 30,000 to 35,000 holes using a 1-in. auger bit
before the brushes needed to be replaced. Their new brushless-motor
drill bored 10 times as many holes before the team was satisfied enough
to end the test.
Going brushless is not primarily about a reduction in maintenance, however.
to Milwaukee’s numbers, you could drill 20 holes every day for nearly
five years before needing to swap the brushes in a conventional electric
motor. Even then, it’s usually a quick job costing only a few dollars
in parts. The real story with brushless motors is in their increased
Run longer and maybe stronger
brushed motor relies on a physical connection between the carbon brushes
and the spinning rotor. In other words, the same brushes that are
delivering electricity are creating drag. This drag wastes energy, and
in a tool powered by a battery pack, energy is a precious commodity. No
brushes, no drag. No drag, higher efficiency.
Makita are claiming up to a 50% increase in run-time for a
brushless-motor tool before recharging the battery. Heavy-handed tool
users may see the biggest payoff in going brushless, because according
to Milwaukee product manager Christian Coulis, “The harder you use a
brushless motor, the better it’s going to perform compared to
No drag also means that a drill or impact driver
will boast a higher torque output, even under load—about 10% to 20%
greater than the average brushed-motor competitor, according to
publicized specs. Some brushless motors also incorporate electronic
controls to help keep the output of the motor constant under a heavy
load. According to Coulis, “The difference between peak torque and
sustained torque on these tools is closer than Milwaukee has ever come.”
The price of progress
worry—your tools aren’t obsolete, and brushed motors aren’t going away
yet. These conventional motors are relatively simple and inexpensive,
and that carries lots of weight in a competitive, cost-driven tool
market. In fact, for all but Festool—a company that has been focused on
brushless motors for years—the new brushless offerings will be sold as
A Bosch representative told me that brush
less motors are costing the company about twice the price of the
conventional brushed motors, but the hope is that the demand will help
to reduce the price. Currently, the price difference to consumers for
Makita’s impact drivers is around $40. I’m told to expect a difference
ranging from $50 to $100 for Hitachi’s new impact drivers and
drill-drivers, and Milwaukee is offering its brushless drill-drivers for
a premium of about $30.
Bottom line: Aside from the slight
upcharge, and assuming that the higher level of electronics doesn’t lead
to unforeseen problems, brushless technology sounds like it will be a
good step forward in cordless power tools. For more on brushed vs.
brushless motors, see “How It Works” from FHB #226.
Editor Test Results:
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