Drives and Controls Magazine

Compact motors are integrated into PCBs

19 February, 2009

A Danish company has developed a technology for incorporating small motors and controllers into PCBs (printed circuit boards), resulting in compact, low-cost machines that do not need gears or conventional cabling.

The motors are created by mounting tiny (1 x 1mm) ceramic piezo pieces onto the PCB to form a stator. A travelling wave generated over the stator surface turns a rotor pressed onto it. The rotor can spin at speeds of 60–120 rpm and produce 1–70Nmm of torque, depending on the stator diameter, the number of piezo pieces and other factors. Several motors can be combined on one PCB (as shown above).

The rotors can start to move in less than 0.4ms, and stop in less than 0.1ms. They offer resolutions of up to 20,000 steps/rev at 0.4ms/step. The PCB motors are said to deliver high starting and holding torques.

“Traditional design methods use PCBs as motor controllers with connections to a physical motor located somewhere in the vicinity of the card,” explains PCBMotor’s chief executive, Henrik Staehr-Olsen. “Our technology builds accurate and powerful motors directly onto the PCB itself. It significantly reduces application costs – and introduces a world of new design opportunities.”

Potential applications for the technology include medical and laboratory equipment, audio mixers, and aerospace instrumentation. PCBMotor believes that the technology could also have applications in robotics and industrial automation.

One specific example cited by PCBMotor is a radio tuner that uses several motors integrated in a single PCB, each tuning a separate frequency. The motors could be controlled by a single driver, also located on the PCB, resulting in a compact assembly that would be cheap to produce using standard components and assembly techniques. The high holding torques of the PCB motors means that they keep their positions when power is removed. A conventional alternative would require several externally mounted motors, each with their own wiring.