New non-contact solution for motor speed sensing

While motor speed is usually measured by means of an internal sensor bearing or an optical encoder with fixed pulse counts, this can have a negative effect on flexibility and storage.

Looking to address this problem, Contelec has launched an innovative new sensor concept. The solution makes use of a slim external sensor to measure the speed of the main shaft – without any physical contact between the magnetic actuator and sensor unit. All that is needed to attach the magnetic actuator is to tap a hole in the main shaft. The sensor unit itself is attached to the reverse of the motor or to the fan housing and aligned. The shape of the sensor has been designed to have a negligible influence on the air flow. The device, available in the UK now from Variohm EuroSensor, has a resolution up to 12bit and an incremental high speed operation up to 10'000 rpm.