Spotlight on Motors and Motion Control

Geared brushless dc motors with selectable components
A line of geared brushless dc motors is available with a toolkit of selectable gearboxes, controllers, brakes, and smart drives. This feature allows users to assemble different configurations for fast prototyping and provides an automated solution tailored to individual needs. Suitable for use in endoscopy, x-ray, and other medical equipment, the motors feature continuous power up to 400 W, speeds between 1500 and 6100 rpm, motor constants up to 103 mNm per square root watt, and maximum torque constants up to 1400 mNm/A. The six models added to this series include two round and four square designs with lengths ranging from 41 to 114 mm. They can be ordered with a factory-mounted optical or magnetic encoder and can also be fitted with electromechanical fail-safe, power-off brakes.
Crouzet North America
Vista, CA

Single-axis voice-coil actuator controller
Simplifying the integration of voice-coil actuators into medical devices, a single-axis voice-coil actuator controller features an onboard PID controller and an external source of position or force feedback. Capable of upgrading commercially available voice-coil actuators to servomotor functionality, the LS-C27 is suitable for use in surgical equipment, metering and dispensing applications, valve actuation, and high-resolution force and position control systems. Selectable command signal ranges include 0–5 V dc, 0–10 V dc, and pulse-width modulation greater than 2 kHz. With a continuous output of up to 1.1 A, the closed-loop current control compensates for such perturbations as varying input voltages or changes in the coil resistance resulting from temperature variations. Requiring 12 to 24 V dc power, the controller is 39 mm long × 32 mm wide and can be mounted directly on the medical device using header pins.  
Enfield Technologies
Trumbull, CT

Controllable step and dc brush motors
Suitable for a variety of medical device applications, a line of controllable step and dc brush motors is available with or without gearing. Used in robotic material-handling applications in chromatographs and blood analyzers, geared or nongeared step motors offer such features as chip-free plastic magnets and precision ball bearings. The geared motors have heavy-duty brass gearing, enabling them to handle heavy loads, and can achieve hundreds of gear ratios up to 6,000,000 to 1. Featuring heavy-duty plastic gearing, the company’s PM synchronous motors, on the other hand, offer the power required to operate therapeutic compression devices. These models can also handle high torque loads while providing quiet operation. Utilizing ball bearings and skewed armatures for log clogging, the company’s dc brush products are suitable for such applications as powering medical pumps.
Hansen Corp.
Princeton, IN

Motion control systems
Compact integrated motion control packages that deliver the benefits of both servomotors and stepper motors offer capabilities greater than either of these technologies in applications requiring brushless technology, according to their manufacturer. MDrive Hybrid systems feature proprietary hybrid motion technology. This hardware-based system for real-time response delivers smooth movement without unintentional stalling, saves energy, reduces heat, allows operation at 100% of motor torque, and operates in torque mode. Used in a range of medical applications, including imaging-equipment automation, the systems are available in two configurations: one in which the motor is integrated with the drive system and the encoder operates with either optically isolated step and direction, torque and force, or velocity and speed inputs; and the other in which the motor, drive, encoder, and fully programmable controller with up to eight I/O lines are integrated.
IMS Schneider Electric Motion
Marlborough, CT

Brush dc motors
A coreless design enables a company’s brush dc motors to deliver high power density in a compact package. Weighing 15 to 53 g, depending on the frame size, Athlonix brush dc motors deliver good speed-to-torque performance with output power up to 9.2 W. Available in 12-, 16-, and 22-mm frame sizes, they are powered by a self-supporting coil that maximizes magnetic flux and turn density for a given diameter. In contrast, typical self-supporting coils have inherent turn-density limitations that affect the magnetic-flux density in the magnetic circuit, limiting power output and motor endurance, according to the manufacturer. The optimized coil design leads to a low motor-regulation factor, with energy efficiency approaching 90%, depending on the motor-load conditions. Offering maximum continuous torque up to 16.5 mNm and fast angular acceleration, the motors deliver high throughput by quickly and efficiently accelerating to the desired speed. As a result, they are suited for use in automation applications such as medical analyzers.
West Chester, PA

Nonmagnetic telescopic linear actuator drive unit
A compact drive system is easy to integrate into existing environments. Designed for use with the RigiBelt nonmagnetic telescopic linear actuator, the drive unit is made of nonmagnetic materials such as aluminum, polyoxymethylene, and other stainless materials. It can achieve speeds up to 300 mm/sec, which is six times faster than the company’s previous unit, and also features higher capacity of 1000 N. Used in such applications as medical scanners, the telescopic linear actuator is made of two reinforced plastic belts that interlock together, much like a zipper, to form a rigid telescopic column. Capable of moving quickly while telescoping in and out, it can provide either horizontal or vertical motion.
Sterling Heights, MI

Dc gearmotors
Four 12-mm-OD miniature dc gearmotors with medical applications are capable of developing maximum shaft torques ranging from 0.28 to 6.94 oz-in. These performance capabilities result from the incorporation of metal spur gears in the gear train. Rated shaft speeds for the gearmotors in the RoHS-compliant LA 12G-344 family range from 1400 down to 40 rpm. Operating at temperatures between 30° and 70°C, the gearmotors have an axial length of 1.023 in. and weigh less than 0.35 oz. Input voltage levels range from 4.5 to 6.0 V dc, and rated current levels for the four models do not exceed 250 mA. The manufacturer can provide many windings, with input voltages of 4 to 24 V dc.
Nidec Copal (USA) Corp.
Torrance, CA