Popular Woodworking 2001-08 № 123, страница 7
terrco Circle #113 on Resource Directory Coupon arrow Letters continued from page 8 watts or kilowatts. The formula, as I am sure you know, is the same all over the world: wattage = volts x amps. The make of tool is not important. A router advertised in your February 2001 issue has a motor rated at 15 amps. By my calculations, wattage = 110 volts x15 amps = 1,650 watts. There are 749 watts for every horsepower, so 1,650/749 = 2.2 hp. In your test it states the router is 3 hp. Could you please explain this difference? Andrew J Ferrie Dordrecht, the Netherlands Editor's Note: The easy way to explain the difference between what the box says the horsepower is and the real power of the tool is to chalk it up to exaggeration. Some manufacturers derive horsepower by using a formula that uses rpms and torque. Other manufacturers use "developed" horsepower, which can be calculated by stalling the motor and seeing how many amps the tool uses to pull itself out of the stall. In truth, even amperage is an inaccurate yardstick for measuring power because some highly efficient motors can produce great torque while consuming few amps. The best measure, in our book, is to compare the torque of the various machines — a statistic that is rarely found on tools except for cordless drills. — Christopher Schwarz, senior editor Even Basic Planers Work Fine I would like to offer a comment on the reliability of my planer, a Delta Model 22-540C. I bought the machine in 1994 and used it to plane all the rough lumber (Eastern white pine, cedar and spruce) we used when we built a 1,200-square-foot cottage and a 16' x 30' deck. Most of the timber was sawn with a Wood-Mizer and air dried. I have gone through two sets of knives so far and the brushes in the motor still have some life left. The machine is still in use and my solution to the dreaded snipe problem is I cut the boards a bit longer, plane them and then trim the ends to length. The only problem I have concerns the flimsy stamped metal table extensions that attach to the machine with a screw/keyhole system. PW John Askitis Eganville, Ontario Circle #116 on Resource Directory Coupon 10 Popular Woodworking August 2001 |
