Spotlight on Motors
Linear actuator
Derived from a product developed for vehicle-idling applications, a linear actuator can be used in peristaltic pumps, pipetting devices, and x-ray equipment. Based on a stepping motor with permanent magnet technology, the 7214 features up to 40 N of force and attains speeds up to 1000 steps per second. In antirotation mode, the actuator has a travel length of 18 mm; without antirotation, 80 mm. Travel length, increment specifications, force, and power supply can be adjusted to suit customer requirements. The actuator, which is also available in a synchronous version, is designed for applications that require position-controlled linear movements. Sonceboz S.A., Sonceboz, Switzerland.Stepping motors
Without increasing the size of its 2564-mm-diam stepping motors, a company has been able to increase their power output by 100%. The motors feature a maximum torque of 35 N-cm and a linear-movement maximum force of 80 N. Medical uses include peristaltic pumps and infusion and dialysis systems. Max Stegmann GmbH, Donaueschingen, Germany.
Hollow-shaft stepping motor
Because it is fitted with a hollow shaft that allows access through the central axis of a motor, a component is suited for tight system integration. The size 23 single-stack dc stepping motor measures 2.25 in. diam by 2 in. long. Bidirectional, the motor is based on a 1.8° step with a noncumulative position accuracy of ±3%. Peak torque is 50 oz-in. Frame sizes, cables and connectors, encoders, brakes, shaft widths and lengths, and special-tooled end combinations can be modified to suit client specifications. The hollow-shaft stepper motor is designed for applications that require smooth, accurate positioning control, high reliability, and a long service life. Eastern Air Devices Inc./Omega Dynamics, Rueil Malmaison, France.
Dc servomotors
Brushless dc servomotors are designed for space-critical applications where reliability and the capability to withstand harsh environments are desired. Self-supporting skew winding and a rare earth magnet enhance acceleration and torque performance while maintaining a suitable power-to-volume ratio. Hall effect sensors are built into the motor to ensure electronic commutation in all three phases. The servomotors have no cogging torque and feature a linear torque/current ratio. A brochure with full technical data is available in four languages. Minimotor S.A.,Croglio, Switzerland.
Autoclavable motors
Dc motors designed for use in medical equipment that operates at high rotational speeds can withstand repeated 20-minute cycles in an autoclave. The motors meet the same ISO standard for sterilization with which the instruments must comply: they can be autoclaved at a temperature of 135°C with 100% relative humidity and 3.6 bar vapour pressure. The 17N, 22BC, 23DT, 28 DT, and 35 NT-series motors can withstand at least 100 sterilization cycles. The R16 and R32 reduction gearboxes, which can be mounted on these motors, are also available in autoclavable versions. Portescap, La-Chaux-de-Fonds, Switzerland.
Induction motor
Because it measures a scant 102 X 62 X 62 mm, a split-phase, permanent-capacitor induction motor was specified for use in a nebulizer. In addition to its compact dimensions, a low 1540-W power rating makes it suitable for precision dispensing of respiratory drugs in spray form. The IM3000 motor also features Class F insulation, low noise levels, and a long service life. EMD Electric Motor Developments, Halstead, Essex, UK.Direct-drive motors
Brushless, frameless motors that provide precise and smooth operation in a compact package are suited for use in direct-drive applications. Elevated continuous torque—from 1.49 oz-in. to 28.9 lb-ft—and peak torque ratings are achieved by means of rare earth magnets. By eliminating gears, pulleys, chains, and belts, the company has been able to simplify machine design and lower the overall system cost. In addition to eliminating backlash, direct-drive technology improves response time and positioning accuracy while reducing overall size and weight, according to the company. Frame sizes range from 0.840 to 9.42 in. Current medical applications of the motors include their use in a heart pump. Kollmorgen Motion Technologies Group, Tadley, Hants, UK.
Stepping motor and driver combinations
An expanded range of five-phase stepping motor and driver combinations includes a model with joint-plate dimensions of 28 mm and a driver that is the size of a credit card. It is reportedly the smallest and lightest such component currently available. The PMC series features a step angle of 0.36° in half-step mode, 0.72° in full-step. Five different reduction gearheads are available with gear ratios from 1:3.6 to 1:30. Without a gearhead, the motor achieves a holding torque of 2.4 and 4.3 N-cm. A 24- and 36-V-dc power supply at 0.35 A/phase can be used for the driver. The PMC series also includes optocoupled input and output signals and pulse-switched half- and full-step operation. Oriental Motor (Europa) GmbH, Neuss, Germany.
Brushless motors
Two-wire brushless dc motors are available in a variety of configurations. Models with fixed- or variable-speed operation that can achieve approximately 30,000 rpm can be supplied; open- or closed-loop speed control is also offered. Some of the motors include the company's proprietary reverse polarity and reverse direction input/output control. The firm also manufactures electronic commutator drives and voice-coil rotary and linear actuators designed for use in medical equipment and instrumentation. BEI Sensors & Systems Co., Kimco Magnetics Div., San Marcos, CA, USA.
