A dc motor offers a service life of 3000 hours continuous duty (sintered bronzebearing version) and produces low noise. The 42-mm-diam unit is rated at a maximum 50-W usable power (at 2000 rpm). It also meets current EMC standards and will meet EN 55011 with the addition of an interference suppression filter (which doesn't add to its size). Medical applications include equipment for dialysis, analysis, radiology, and orthopedic rehabilitation. According to the manufacturer, the reliability of the motor's high-torque gearbox has been tested over several thousand hours of operation, both continuous and with alternating loads. Crouzet Corp., 3237 Commander Dr., Carrollton, TX 75006.
Motors and gearmotors
A company has expanded its range of motor and gearmotor customization capabilities with new output-shaft options that permit the addition of pressed-on or machined features as well as variations in material, length, and diameter. The shaft of any of the company's dc brush-commutated and brushless motors or gearmotors can be customized with a flat, journal, keyway, cross hole, slot, groove, gear, clutch, or pulleywithout affecting product delivery schedules. In addition, designers can combine these features to meet application requirements. Pittman, 343 Godshall Dr., Harleysville, PA 19438.
For designers of surgical or dental handpiece and diagnostic equipment, a company offers size 5 (0.5-in. OD) motors that deliver high-speed and high-power-density motion control. The company can develop autoclavable brushless dc motors in packages custom designed to fit customer specifications. Choices include speeds to 150,000 rpm; in-line gearheads; hollow-shaft, cannulated designs; custom mountings and shafts; extended lengths; and standard or custom drives. Dynamic braking and soft-start circuits are also available. Transicoil, 2560 General Armistead Ave., Norristown, PA 19403.
Canned stack motors
A line of stepper motors is suitable for medical device and instrumentation applications. The PF series of canned stack motors range in diameter from 25 to 55 mm, with step angles of 15°, 7.5°, and 3.75°. These motors can be modified to fit specific applications with mechanical variations, winding changes, and connector options. Application engineering support and product documentation are available on all products. Nippon Pulse Motor Co., Ltd., No. 16-13, 2-chome, Hongo, Bunkyo-Ku, Tokyo 113, Japan.
Brushless dc motors
A line of 1.7-in.-diam brushless direct-current motors provide high performance in a compact package. The brushless dc motors are designed for use in applications that require precise rotary motion. Available in a variety of compact package lengths, the motors cover a significant range of torque constants, from 5 to 25 oz-in./A. The high torque-to-inertia ratio created by them allows for rapid start/stop capability. Ametek, Rotron Technical Motor Div., 627 Lake St., Kent, OH 44240.
A stepper motor delivers high performance in a very thin package. Just 3/8 in. thick and 3.15 in. diam, the 80000-series motor is suitable for applications with limited space requiring accurate positioning and high torque. The motor has a 3.75° step angle and provides up to 25 oz-in. of torque. Its standard configuration includes ball bearings. Coils are available in bipolar or unipolar configurations. Haydon Switch & Instrument Inc., 1500 Meriden Rd., Waterbury, CT 06705.
Toothless, brushless dc motors are suitable for use in surgical handpieces and tools as well as blood and fluid pumps. The units are autoclavable and speeds from 3000 to 200,000 rpm are available. They feature cool operation, high efficiency, and high power density. Also available are planetary gearboxes, integral electronics, and encoders. Koford Engineering, 1948 University Ln., Lisle, IL 60532.
Miniature dc motor
A 0.118-in.-OD bidirectional brushless dc motor is combined with a 0.134-in.-OD gear train, creating the smallest brushless dc gearmotor available, according to the manufacturer. The smoovy gearmotor develops continuous torque values of 0.07 oz-in. over the gearmotor's speed range of 0 to 1200 rpm (gearmotor shaft speed). The planetary gearhead can operate safely at radial loads approaching 2.2 oz and axial loads approaching 7.0 oz. Unloaded backlash is 1° nominal, and total gearmotor friction torque does not exceed 0.0021 oz-in. RMB, 509 Marin St., Ste. #221, Thousand Oaks, CA 91360.
Permanent-magnet stepper motor
A 15-mm permanent-magnet stepper motor produces more than 0.5 oz-in. pull-out torque at 200 pps. The small size and the ability to operate at low current levels make the Model 15M020D1B suitable for applications where space and power demands are critical, such as in fluid analyzers, pumps, and syringes. Thomson Industries Inc., 2 Channel Dr., Port Washington, NY 11050.
A 2-in. spur gearbox/dc motor is available with optional features such as optical encoders, noise suppressors, custom shafting, custom leads and terminations, custom mounting, rear shaft extensions, custom gear ratios, and different voltages and performance ratings. The gearbox/motor has a life rating of 1000 hours of continuous duty with a 150-oz-in. load torque at 75°F ambient. Maximum torque is 250 oz-in. Hansen Corp., 901 S. First St., Princeton, IN 47670.
A hysteresis ac synchronous motor operates at high speeds with low speed variation, a much desired trait in high-performance medical and optical applications. The size 44 (4.38-in.-OD) three-phase, single-speed motor operates at 15,000 rpm continuous while maintaining a smooth, quiet, and efficient constant-speed drive. The torque rating is 13.5 oz-in. with continuous output of 1/5 hp, and the voltage rating is 100 V ac with 500-Hz input. Eastern Air Devices Inc.,
1 Progress Dr., Dover, NH 03820.
A direct-drive CE-marked motor system provides high torque at low speeds and highly precise positioning. The YS-series Megatorque is available in nine standard sizes. The motor delivers a repeatability of ±2.1 seconds with up to 177 ft-lb torque at a speed of 3 rps. It has full closed-loop control. The motor's design eliminates all gears, and its brushless structure and permanently lubricated heavy-duty bearings provide maintenance-free operation. NSK Corp., 250 Covington Dr., Bloomingdale, IL 60108.
Quiet dc motors
A complete line of brushless dc motors is available for applications that require high speed, low noise, and smooth operation. The Silencer motors are available in diameters from 1.2 to 4.0 in. and lengths from 1.3 to 5.5 in. They offer continuous torque ratings from 2.4 to 519 oz-in. and speeds up to 20,000 rpm. Built for rugged applications and environments, the motors feature bonded rare earth magnets and an aluminum housing. Litton Systems Inc., 1213 N. Main St., Blacksburg, VA 24060.