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Hollow-shaft stepper

Article-Hollow-shaft stepper


Hollow-shaft stepper

A hollow-shaft stepper allows access for electrical and optical cables through the central axis of the motor. The 2.25-in.-diam motor is bidirectional and based on a 1.8° step with noncumulative position accuracy of ±3%. The peak torque rating is 50 oz-in. Other features include permanently lubricated high-precision ball bearings and a range of windings to match a variety of unipolar and bipolar drives. Eastern Air Devices Inc., 1 Progress Dr., Dover, NH 03820-5449.

Zero-cog motors

According to the manufacturer, a combination of a slotted stator with a rotor design results in a line of ac brushless motors that are virtually cog-free. Specifications for the PSA series include optional IEC frames, power ratings of 230 or 400 V ac, and a rated torque from 0.76 to 20.9 N·m. API Motion Inc., 45 Hazelwood Dr., Amherst, NY 14228-2096.

Brushless dc motors

Featuring slotless construction to prevent magnetic cogging, brushless dc motors offer long life. Slotless design also reduces inductance, improving current bandwidth for increased control and acceleration. Elcom II brushless motors are available in three frame sizes and can be customized with Hall sensor feedback for six-step commutation at 60 electrical degrees. Integrated Hewlett-Packard optical encoders can be incorporated for reliable position, velocity, and direction feedback. Pittman, 343 Godshall Dr., Harleysville, PA 19438-0003.

Replacement motor

A 3-in.-OD brushless dc motor has an operating life of more than 20,000 hours and is available in 12- and 24-V models. Designed as a two-wire drop-in replacement for brush-type dc motors, the DurA-tek 3.0 offers a two-wire electrical hookup. Other features include multispeed operation, over-temperature shutoff, and transient overvoltage protection. The motors offer both internal and external controls, and are available in heights of 5.19 and 4.27 in. Ametek, Rotron Technical Motor Div., 627 Lake St., Kent, OH 44240.

Dc motor

Suitable for use in handheld surgical tools and dental equipment, a brushless dc motor enables precise speed control. The size-5 MediTorq is constructed of stainless steel and offers speeds up to 100,000 rpm. The motor can be equipped with a hollow shaft for irrigation needs, planetary gearheads for increased torque and reduced speeds, and threaded housing and shafts for attachment to equipment. Transicoil Medical LLC, 2560 General Armistead Ave., Norristown, PA 19403-5214.

Miniature motor

A 0.007-in.-diam brushless motor and planetary gearhead is the world's smallest available gearmotor, according to its manufacturer. The BL 1900 series uses a bipolar rare-earth permanent magnet for the motor rotor, Liga cast gears in its gearhead, and a sensorless electronic commutation system, resulting in a continuous output torque of 0.02 oz-in. and an intermittent output torque of 0.042 oz-in. The motor is capable of input speeds of 20,000 rpm and continuous output speeds of 100,000 rpm. MicroMo Electronics Inc., 14881 Evergreen Dr., Clearwater, FL 33762-3008.

Stainless and paint-free motors

For applications that require sanitary and sterile conditions, a company manufactures stainless and paint-free ac and dc motors. Also offered are low- and standard-inertia brushless servomotors with a torque range from 3.9 to 366 lb-in. and 14.4 to 177 lb-in., respectively. The company also produces a line of linear motors for the medical device industry. Baldor Electric Co., P.O. Box 2400, Fort Smith, AR 72902-2400.


A brushless servomotor has a continuous stall torque rating of 15 oz-in. and a peak rating of 72 oz-in. at 6000 rpm. The AVS-M172 motor has a 1000-line encoder that measures 1.7 x 1.7 x 2.56 in. The motor can be driven by the company's digital ac servo drive system, which uses sine wave vector commutation to produce smooth motion without torque or velocity ripple. The Advanced Vector Servo system, which performs closed-loop speed and position control using step and direction signals, can replace a stepper system. Bearing Engineers Inc., 27 Argonaut, Aliso Viejo, CA 92656.

Rotary servomotors

A line of rotary servomotors features a magnetic circuit, thermal management, and winding design, which provides the maximum copper fill per slot and low thermal resistance. MFM rotary servomotors produce 114-in.-lb continuous torque and 340-in.-lb peak torque. NEMA frame sizes 17, 23, 34, and 42 and four frame sizes ranging from 40 to 115 mm are available. An optional resolver and brake can be installed along with standard steel disc encoders. Bayside Motion Group, 27 Seaview Blvd., Port Washington, NY 11050.

Brushless motor

A brushless dc motor with integrated electronics offers 10,000 to 20,000 hours operating life and 10 to 60 W output power. Options include integrated closed-loop speed control circuitry and a variety of planetary gearboxes. The motors are suitable for electromedical applications such as dialysis machines, analyzers, pumps, and portable systems. Crouzet Corp., 3237 Commander, Carrollton, TX 75006.

Compact motor

A direct-drive motor features an interchangeable control unit and motor, built-in autotuning, high resolution, full closed-loop control, and zero backlash. The JS series Megatorque motor has a hollow structure that allows for the insertion of wires or pipes. Specifications for the four models include a repeatability of ±2.1 to ±3.2 arc/sec, torque range from 1.5 to 10.3 ft-lb, and diam between 75 and 130 mm. NSK Corp., Precision Products Div., 250 Covington Dr., Bloomingdale, IL 60108-3106.

Dc motor

Specifically designed to withstand autoclave sterilization, a 1.1-in. diam brushless dc motor is suitable for use in battery-powered, handheld surgical devices. The N11 series motor features a cannulated shaft for insertion of a pin or wire and eight pins for connection to a brushless motor controller. Specifications include continuous torque of 10 oz/in. and speeds in excess of 30,000 rpm. The series is compatible with the company's size 13 planetary gearboxes, clutches, and brakes. Astromec Inc., 2950 Arrowhead Dr., Carson City, NV 89706-0488.

Custom motors

A company offers custom-fabricated brushless dc motors with built-in controllers for use in medical applications. Materials used include neodymium, iron, boron, samarium cobalt, and Hyperco 50. Depending upon temperature requirements, the company can use either plastic or ceramic chips. Brushless rotor and stator kits are also available. Arc Systems Inc., 2090 Joshuas Path, Hauppauge, NY 11788.

Stepper motor

Incorporating a multifunctional, inside-out hollow-core design, a motor can be converted into a ball-screw linear actuator by mounting a miniature ball-screw to its front shaft face. A hollow shaft in the 34 frame IOS motor allows electrical or pneumatic lines to be directed through its center, enabling the stacking of more than one motor. The through hole is stationary to prevent cables from being chaffed by a moving hollow shaft. Operating speed can reach 3000 rpm. The motor is compatible with bipolar chopper microstepping drivers. Intelligent Motion Systems Inc., P.O. Box 457, Marlborough, CT 06447.

Dc motors

A line of brushless dc motors produces low cogging torque and is suitable for a variety of applications including pumps, blowers, centrifuges, and high-speed scanners. Performance specifications include speeds up to 20,000 rpm, a continuous stall torque of more than 32 oz-in., and peak torque of 100 oz-in. Permanently lubricated, double-shielded ball bearings are standard. High-energy bonded neodymium and bonded samarium cobalt magnets are available depending on application and temperature requirements. Servo Magnetics Inc., 6660 Variel Ave., Canoga Park, CA 91303.

Linear servomotors

A company offers a series of directly driven, brushless linear servomotors with a high-efficiency magnetic circuit design. The BLM, BLMC, BLMUC, BLMH, and BLMX series motors comprise a moving forcer coil and a u-channel rare-earth magnet track, both noncontacting parts. A stackable magnet track system with a symmetrical mounting-hole pattern allows for unlimited travel lengths. Continuous force ratings range from 8.2 to 1183 lb, with peak force ratings from 33 to 1064 lb. Aerotech Inc., 101 Zeta Dr., Pittsburgh, PA 15238.

Coil motor

A 12-mm-diam rhombic moving coil motor incorporates an ironless rotor, which allows for zero cogging and accurate control. The A-max motor is available with a single or passing shaft and has ratings of 0.5 or 0.75 W. Other standard options include ball bearings, sleeve bearings, terminals, and leads. Matching gearheads with ratios ranging from 4:1 to 1118:1 can deliver up to 75 oz-in. of intermittent torque. Maxon Precision Motors Inc., 838 Mitten Rd., Burlingame, CA 94010.

High-speed motor

With a peak output of 176 W, a brushless dc motor is suitable for use in surgical and dental handpieces, small grinders, and engravers. The 23A103 motor features slotless construction, high-energy rare-earth magnets, and 40,000 rpm no-load speed with a no-load current of 150 mA. A high-cycle autoclavable version is available. Optional features include planetary gearboxes and encoders. Koford Engineering, 1948 University Ln., Lisle, IL 60532.

Induction motors

Terminal box-type ac induction motors allow a power cable to be fixed with the cable clamp and seal connector for security purposes. Because the lead wires are inserted directly into the terminal block, terminal crimping is not required. The series includes motors with 25-, 40-, 60-, and 90-W output power; 100 V ac, 50/60 Hz to 230 V ac, 50/60 Hz input power; and gearhead ratios from 3:1 to 180:1. All products conform to UL, CSA, and EN standards. Oriental Motor U.S.A. Corp., 2510 W. 237th St., Torrance, CA 90505.

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