Abstract: Motor control apparatus is described that is used in a printer that prints on a paper web coming from a roll of paper and has two-sided printing capability using two print mechanisms. The motor control apparatus controls power to several DC motors that either move the paper web from a roll through the printer or provide back tension to the paper web. The control circuits sense paper travel speed and motor loading and thereby sense the effects on paper tension caused by others of the control circuits. The interaction of motor torques provided by the control circuits maintains constant tension on the paper web throughout the printer and thereby assures that there is front to back printing registration on each two-sided printed sheet, and also assures that there is top to bottom centering registration of printing on each sheet of paper when the paper web is cut into individual sheets of paper.

Abstract: An electric motor run and brake control circuit for controlling alternating current to a three-phase motor in which the circuit is operated by a single logic level input signal. When the input signal is low, a run relay is closed and AC power is applied to the motor. When the input signal goes high, the run relay is opened and the motor is braked for a fast stop. A brake capacitor and charge resistor limit both the time during which braking current is applied and the repetition rate of braking cycles.