Originally Published September 2000

Spotlight on Motors

Stepper motor

A high-torque permanent-magnet stepper motor measures 55 mm diam and 27 mm long. The Series 55M motor, which is available in unipolar and bipolar versions, produces 176.5 mN.m pullout torque when driven with a 24-V-dc chopper drive. Offered in the most commonly used frame-size configurations, the motor is suited for medical and HVAC pumps among numerous other applications. Designed for automated assembly, the component can be easily adapted to accommodate mounting and lead egress positions and a range of bearing systems. Thomson Airpax Mechatronics, Barnstaple, Devon, UK.

Compact dc motor

Suited for use with medical pumps and battery-operated equipment in which reliable operation is critical, a dc motor measures 17 mm diam and 18 mm long. The rare earth magnet enables accelerations up to 12,400 rpm, and the rotor has an iron-free core to ensure minimal loss and low inertia. A unique commutation system minimizes friction, thus improving efficiency and the product's life span. API Portescap, La Chaux-de-Fonds, Switzerland.

Hybrid linear actuator

Fabricated using proprietary manufacturing processes and incorporating a stainless-steel acme leadscrew, a linear actuator is suited for applications that require precise positioning, rapid motion, and a long service life. Unlike with other actuators, the bearing preload adjustment does not protrude from the motor. The product is available in resolutions ranging from 0.00012 to 0.00192 in. per step; this model can be microstepped to achieve even finer resolutions. Haydon Switch & Instrument Inc., Waterbury, CT, USA.

Autoclavable motors

Brushless dc motors can withstand more than 1000 autoclave cycles. The motors are available in sizes 5, 8, and 10 with operating voltages ranging from 12 to 48 V dc. They attain speeds from 3000 to 100,000 rpm. Gearheads can be specified in sizes 5 and 8 with ratios from 3:1 to 256:1. The low-noise motors feature numerous customization options; control electronics are also available. Applications include surgical tools, bone saws, dental devices, and cleanroom equipment. Transicoil, Norristown, PA, USA.

Stepper motors

NEMA-size-23 stepper motors feature high torque and a design that facilitates drop-in replacement. Suitable for use in new systems or to upgrade existing systems, the motors can boost power more than 1.5 times compared with conventional similarly sized stepper motors. The 2.22-in. square motors measure 1.75, 2.21, and 3.09 in. in length and attain holding torques up to 250 oz/in. Numerous options are available for design flexibility, and several stock windings for either bipolar or unipolar drives can be specified. Eastern Air Devices Inc./Omega Dynamic, Rueil Malmaison, France.

Miniature motor

An electronically commutated dc motor has Hall sensors, measures 6 mm OD, weighs only 2.8 g, and attains speeds up to 100,000 rpm. The motor has a 1.2-W assigned power rating. Despite its size, the motor maintains a low operating temperature. At a no-load speed of 80,000 rpm, the housing temperature does not exceed 52°C. Constant operation at high performance levels can be maintained up to the maximum operating temperature of 125°C. Maxon Motor AG, Sachseln, Switzerland.

Motion control system

A motion control system incorporates a bipolar stepper-motor microstepping drive and programmable indexer with expandable I/O and multiple communication ports running off of a single supply. The compact panel-mounted assembly comes in two power ranges: the MicroLynx-4 runs at 12 to 48 V dc with 3-A rms output, while the MicroLynx-7 runs at 24 to 75 V dc with 5-A rms output. I/O lines can be customized to suit user applications. Six isolated lines are standard; optional expansion modules can be added for a total of 24 lines. Intelligent Motion Systems Inc., Marlborough, CT, USA.

Linear actuator

Linear actuators based on a company's 40-, 56-, and 86-mm-diam stepper motors and standard M4, M5, M6, and M8 leadscrews achieve push and pull forces up to 250 N at a resolution of 0.002 mm per step. Horizontal and vertical travel or stroke is limited only by the spindle length. The actuator will not overrun and does not require a brake for vertical stops. In addition to metric leadscrews, acme screws with 5- and 20-mm pitches are available. They can achieve speeds up to 400 mm/sec. Nanotec Electronic GmbH, Landsham, Germany.

Brushless dc motors

High-energy-density motors excited by rare earth magnets feature integrated or separate electronic power controls. The controls enable operation of the motor in stepper, synchronous, or brushless dc mode. The motors have an operating voltage range starting at 10 V dc and a power rating that attains 0.75 kW. Speeds up to 30,000 rpm can be achieved. Device applications include fan, pump, servo, and compressor drives. The motors are currently used to drive the front feed of a printer connected to an E-beam linear accelerator. Airscrew Ltd., Sunbury on Thames, Middx, UK.