Review

Motors and motion control products made some technological improvements in the past year. For new motors, the emphasis was on smaller size, greater power and longer life. For new motion control products the emphasis was on ease of use and faster time to market. Other products in this category, such as actuators and encoders, also exhibited new technological developments. Here's a sampling of the products that embodied these improvements.

The EC 16 brushless motor from Maxon Precision Motors (maxon.com) has no mechanical brushes to wear out, which greatly prolongs motor life and minimizes electrical noise. And by utilizing high-energy neodymium magnets, the motor exhibits high responsiveness while minimizing overall size. Another motor from the same company, the RE08 series, incorporates rare earth magnets in a package measuring just 8 mm in diameter and 16 mm in length. The magnets maximize available torque, while a patented rhombic moving-coil design promises long life, low electrical noise, fast acceleration, and high efficiency.

The LO-COG 22 mm, brush-commutated iron-core dc motors from Pittman (pittman. com) deliver power comparable to ironless core (coreless) motors. The family of motors employs a skewed, five-slot armature design and bonded neo-dymium iron boron magnets to achieve maximum peak torques up to 10.2 oz.-in. and speeds up to 8,550 rpm.

On the encoder front, Encoder Devices (encoder. com) used a novel technology in their new rotational magnetic encoders. A newly available solid-state magnetic rotary encoding technology consists of a diametrically polarized magnet imbedded into the end of the rotating shaft and positioned over an ASIC sensor. When the magnet is rotated, the alternating poles cause the multiple Hall-effect sensors on the chip to output two sine waves 90° out of phase with each other. This information is decoded by the ASIC to generate various electrical outputs, including two-bit quadrature, synchro-serial (SSI), analog voltage, or binary parallel.

An example of a new actuator design was the Size 14 hybrid external linear actuator from Haydon Switch & Instrument (hse-inc.com). It incorporates a rotating acme stainless steel lead screw into the motor's rotor. Shaft-to-lead screw couplers are not needed with this design. A mating nut translates along the lead screw, and as the motor steps, the lead screw rotates but does not advance. The actuator actually replaces the need for four separate components: a motor, coupler, lead screw and nut.

Motion control products got a boost with the launch of the iMOTION family from International Rectifier (irf.com). This family promises to simplify the design of motion controls, as well as to increase the performance and efficiency of these controls. Embracing both hardware and software, the iMOTION family includes: an integrated design platform for sensor-less control of motion; a motion control development system; a linear current-sensing motor and inverter drive chipset; new IGBTs; and a new 16A power module.

In another control application, the AXU Series systems from Oriental Motor Corp. USA (orientalmotors.com) are designed to provide tight speed control of motors delivering 10W to 90W of power. The high-performance brushless DC speed control systems consist of a motor and control unit. The series provides speed regulation of ±1% maximum with voltage, ±1% maximum with temperature, and -2% maximum with load.

—Joe Desposito

Outlook

Squeeze Play
Let's face it. Motors are an essential part of today's miniaturized electronics—a digital camera with zoom lens comes to mind. So expect to see new motors, actuators and encoders designed to squeeze into ever smaller spaces. On the other hand, these components can't be the equivalent of 97-lb. weaklings, so expect breakthroughs in torque power, even at the smaller motor dimensions.

As for motion control, the trend here is to make things simpler for the design engineer. Give designers everything they need in one package to make products easier to design and to accelerate time to market. This trend will no doubt continue as designers seek to maximize their productivity.

—JD