Cine projector spool transport regulation circuit - has separate spool motors with electronic regulation and transport reversal switch

摘要

Control and regulating electronic circuitry governs the speed and direction of film winding in a projector equipped with spool motors. The take-up spool has its own motor (M1) operating at the same potential (UR) as the feed and rewind spool motor (M2). Each motor is provided with current limiting resistors (R1, R2) and the voltage across these is connected via diodes (D5, D6) into the transistorised and operational amplifier regulating circuitry. The feed rewind spool motor (M2) is equipped with changeover switches (9, 10) to reverse current flow and the direction of film transport.