Matchbox-sized servo spawns compact integrated motor

The German firm Elmo Motion Control has developed tiny digital DC servo drive, about the same size as a matchbox. Elmo has also joined forces with an Italian motor-maker, the Motor Power Company (MPC), to create a compact integrated brushless motor based on the new drive.

The tiny drive (above), called the Whistle, is designed for mounting onto multi-axis PCBs, where it can control 1.5 axes. The 50g drive, which measures 55 x 15 x 46.6mm, can deliver 500W of continuous output power and 1kW of peak power. It dissipates less than 4W and is said to operate with an efficiency of more than 99%.

The drive can operate in current, velocity, position or "advanced position" modes, to control DC brushless or brushed motors, linear motors, or voice coils. It can provide sinusoidal or trapezoidal commutation with vector control, and can operate by itself or as part of a distributed, multi-axis system in a real-time network.

The Whistle drive supports a variety of feedback options including incremental encoders, Hall sensors, tachometers, resolvers and interpolated sin/cos encoders. It incorporates RS-232 and CANopen communications, and operates from 9-100V supplies.

The motor-integrated version, called the Duet (shown above), is a one-axis positioner based on MPC`s Tetra Compact brushless motor. It will be available in various models with torque ratings from 0.16Nm continuous (0.43Nm peak, at 3,000 rpm) to 2.8Nm continuous (5.4Nm peak, at 1,900 rpm).

"The advantages of these new motor designs are very clear," says Horst Malchow, Elmo`s managing director. "Not only the ultra-compact size of the unit itself, but also the reduced overall size of the application, mean pure cost savings for the machine-builder. On top of that the elimination of an extra component saves cabling. This saves time when building the machine."

Elmo and MPC have also collaborated on a second integrated motor - another one-axis positioner, called the Harte - based on the larger Harmonica drive and Tetra motor. This is available in versions with torque ratings from 1.2Nm continuous (3.36Nm peak at 3,000 rpm), to 2.8Nm continuous (5.64Nm peak, 3,000 rpm).