Contactless optical revolution rate measurement - uses foil body markings reflecting light in direction of incidence with photocell clear of dirt

摘要

A device is for contractless measurement of the speed of rotation of rotating bodies, in partic. of starter motors and dynamo generators. It uses optical illumination and detection methods with markings on the rotating body and is designed to avoid contamination of the optical transmitter and receiver by dirt centrifugally thrown from the body. The device also permits optional arrangement of the transmitter and receiver relative to the body axis and avoids stray reflection effects. The transmitter (14) and receiver (15) are arranged at an acute angle to the rotation axis (10). The body markings (13) consist of foil which reflects light in the direction of incidence.