GB567885A - Improvements in or relating to electric motor drives for printing presses and other machines - Google Patents

Abstract

567,885. Control of two motors. IGRANIC ELECTRIC CO., Ltd. April 15, 1943, No. 6052. Convention date, April 24, 1942. [Class 38 (iii)] A printing press is driven at high speed directly by a large motor LM, and at low speed by a small motor SM through reduction gearing and an electromagnetic clutch energized by a coil C1. Transfer from drive by the motor LM to the motor SM is dependent on the speed of the large motor as determined by a voltage relay V across the rotor circuit, a centrifugal switch or a tachometer. Alternatively, a timedelay may be imposed upon the transfer. Momentary closure of " Reset " button 15 starts warning bell 21 and causes energization of clutch coil C1. Closure of " Inch " button 11 stops the bell and energizes coil Sl of the small motor contactor S, and a mechanical brake on the small motor is released by energization of coil B. Opening of button 11 stops the motor SM, de-energizes the clutch coil C1 and necessitates reclosure of button 15 prior to another start of the press. Closure of " On " button 12 similarly causes closure of contactor S, and additionally energizes a pilot motor 5 to raise the cross-head of a controller 3. As the cross-head rises, coil L1 of large motor contactor L is energized, and coil S1 is deenergized, whereupon coil R1 of rotor contactor R is energized and the clutch coil C1 is deenergized. The controller 3 accelerates the motor LM to full speed if the button 12 is held closed. Closure of " Off " button 13 energizes the pilot motor 5 to lower the cross-head and decelerated the motor LM, re-energize the contactor coil S1 and de-energize the contactor coil R1. When the large motor has slowed down sufficiently, the coil V is energized to cause re-energization of the clutch coil C1. Momentary closure of " Stop " button 14 in any running position of the controller 3 causes opening of both contactors Land S, reversal of the pilot motor 5 and energization of the clutch coil C1 until the controller 3 is returned to its initial position so that the brake is effective to stop the press. Specification 539,203 is referred to.