When a compact servo motor used in their weather balloon tracking antenna ceased being produced, South African company InterMet needed to find a new manufacturer to provide a drop-in replacement.

The discontinued motor had a very low profile which enabled it to fit within the base plate of the antenna’s turntable mount. It also had a rear shaft for an encoder to provide position feedback.

All the requirements were met with the GM9 brushed pancake motor fromPrinted Motor Works Ltd. The motor has an iron-free armature, producing zero cogging and no torque ripple under load. This ensures the motion is extremely smooth and meets the high angular precision required for the scanner, as any ripple would have been amplified by the high reduction ratio strainwave gearbox.

The motor is suitable for low voltage remote area operation, powered from a battery pack. At 22V with 8.7A, the GM9 motor’s rated speed is 3000rpm, producing 36Ncm of torque.

“We can replace or repair most printed armature motors,” said Nick Revels, Applications Engineer at PMW. “Drop-in replacements we have produced in the past include Infranor Mavilor, Kollmorgen, Yaskawa print motors and the KN series from PMI.”

The iMet-1600 is a military grade tracking antenna / receiver, designed to
track radiosondes using RDF or GNSS techniques, to provide users with
upper air meteorological data under all operating conditions now uses the PMW GM9 electric motor





PMW Dynamics