Contactless textile spindle speed measurement - by oscillator circuit coil facing recess producing oscillations at two amplitude levels

摘要

The speed of spindles of textile machinery can be measured without any mechanical contact if the spindles have a nonhomogeneity such as a keyway or a recess on the periphery. A coil which faces it is part of an oscillator circuit supplied via a rectifier. The oscillator output is amplified and converted by a Schmitt trigger into square pulses. These are measured by a frequency meter and indicate the spindle speed. This method is less affected by interferences than permanent magnet systems. It can be used to indicate any speed, including zero.