Detection of direction of rotation of e.g. fan - using 3 scanners to detect raster signal and apply it to flip-flops which control 3 stores

摘要

The detection method is to ascertain the direction of rotation of a revolving component, esp. a fan of an electric machine. First, a raster is scanned by polyphase scanning by optoelectronic, electrostatic or magneto-electric means. Signals so obtained are processed by an evaluation logic system which delivers a signal showing the director of rotation. Three scanners, spaced at phase angles of 120 degrees detect the same flank of a raster signal and apply it to a monostable flip-flop which delivers it as a pulse to electronic stores. Pulse of a first of the flip-flops sets two stores, and each store is reset by the pulse of one of the other two flip-flops.