Motor control and web material drive system

摘要

A motor switching and control circuit is disclosed in which the direction of transport of web material transferred between two reels is reversed by detecting a condition requiring reversal, generating a reversing signal in response to the detected condition, and switching the direction of rotation of an AC motor in response to the reversing signal. Both motor direction switching and reversing condition detection switching are accomplished at substantially zero motor current flowing through and zero motor voltage across the contacts of any circuit switches, thereby eliminating radio frequency interference and logical noise generation during switching. The circuit is particularly useful in connection with the ribbon control drive in an impact printer such as a matrix printer.