Motor Size Matters

Smaller products are fueling the need for smaller motors, and the need for more torque that fits into thinner, smaller and lighter product designs. Manufacturers of miniature motors are in the business of packing performance into smaller and smaller packages. With external motor-diameter and motor lengths measured in a few millimeters, the power/volume ratio of these products continues to expand.

To maintain a supply of innovative new products, suppliers are turning to high energy magnets, new winding technology and automated motor assembly techniques to boost performance. Makers of micro motors face the same issues that limit all motor design efforts, and continue to focus on delivering higher power-to-volume ratios, motor efficiency and reliability.

16 MM BRUSHLESS MOTOR

Maxon's EC 16 mm brushless motor utilizes high-energy neodymium magnets to create a very responsive motor while minimizing overall size. The motor is electronically commutated for extremely long motor life and minimizes electrical noise. Motors are available in three versions to provide for maximum flexibility and use with hall sensors, sensorless or with integrated electronics. With a weight of 58g (2 oz), the 16 mm (0.63 inch) diameter motors measure 56 mm (2.2 inch) in length not including shaft or cables. Continuous output power is 40W, while the maximum speed is 60,000 RPM. Maximum continuous torque is 15.6 mNm (2.2 oz-in). Matching gearheads and digital encoders are also available to complement the motors, as well as Maxon servo amplifiers. Due to their high performance in a compact package, the EC 16 motors are particularly suitable for a variety of applications including hand-held devices, air samplers, robotics, automation, as well as medical and positioning applications.

MINIATURE LINEAR SERVOMOTOR

A new 4 mm linear shaft diameter servomotor from Nippon Pulse America is the smallest in their line-up of products. The combination of its small forcer size (10 × 10 mm), a total weight of 9g and strokes as long as 40 mm make the motor a suitable replacement in piezo-type applications. The motor is quiet due to the absence of friction since the only mechanical contact section is the linear guide. Cogging is eliminated by its coreless construction, and because its design has no backlash. The linear shaft motor's high motor stiffness allows it to be used in precision positioning applications where a resolution of 0.09 nanometers is achievable. Using the linear shaft motor, users will find virtually no fluctuation in speed. Durable construction makes it possible to use the motor in harsh conditions including operation underwater or in a vacuum.

SMALLEST QUICKSILVER SERVOMOTOR

QuickSilver Controls Inc. has expanded its current line of high-torque, direct-drive servomotors to include a NEMA 11 frame (QCI-M11-1) model. With a face plate of 1.1 inches, a length of 2 inches and weighing only 5 oz, the M11-1 is designed to fit in all those small places. The NEMA 11 frame motor generates 9 inch-oz of continuous torque and comes with a 4000 count/rev encoder. When combined with QuickSilver's line of servo controller/drivers, this motor creates a high torque servo control system at speeds up to 4000 RPM. The motor provides an ability to handle inertial mismatches of 100:1, and is designed for driving large flywheel loads without additional gearing required. The M11-1 conserves power, requiring the controller to draw only 1.3 amps from the 12 to 48V power supply.