Power tools are more feature-rich than ever. For example, circular saws use lower amps and higher rpms to provide efficient, lower-cost operation. Compact circular saws come with 1¾-inch cutting depth and a bevel of up to 45 degrees, carbide-tipped blades that last longer, edge guides, and a vacuum adapter for dust collection. Reciprocating saws offer more strokes per minute and dual selectable stroke length for greater efficiency. Impact wrenches come with ½-inch drive, impact sockets, drive bits, and nut drivers, as well as a ¼-inch quick change drive adapter for smaller fasteners.
Many major suppliers also have added brushless motors to their lines. Brushes are replaceable, spring-loaded carbon blocks that make contact with the rotor to generate rotation energy. This contact causes resistance, heat, arcing, loss of power, brush wear, and scored rotors. Brushless motors employ a plain cylinder which generates a contactless electromagnetic field to transfer power between the stator and the rotor.
In tests, using brushless tools result in longer motor life, higher drill and driver speed, and longer battery life than brush-motor-driven tools. Brushless tools can cost 30 percent more than tools with brush motors, but for professional users, the cost might be worth it for longer run time because of the way brushless drives adjust power output to resistance, resulting in less average power drain over the range of resistance. The lighter resistance yields less power output and better ergonomics.
An excellent combination for a tools arsenal that delivers longer life cycles would be brushless tools, all of which fit the same LI battery and charger system. This combination initially would cost more, but it would provide longer service life and lower life-cycle costs, considering first cost, maintenance, ergonomics, run time, and disposal.
Thomas A. Westerkamp is a maintenance and engineering management consultant and president of the work management division of Westerkamp Group LLC, www.westerkampgroup.com.
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