GB531319A - Improvements in or relating to control apparatus for effecting sequential operation of power-operated devices - Google Patents

Abstract

531,319. Control of several motors. WATFORD ELECTRIC & MANUFACTURING CO., Ltd., and COATES, H. June 28, 1939, No. 18887. [Class 38 (iii)] [Also in Group XXXV] An electrically driven timing-controller 34 and an electrically driven selector-controller 35 are associated with a member of electrically controlled devices, e.g. soot blowers, which may be driven by any kind of power supply, and controlled by electrically operated means such as switches or valves, so that a cycle of operations determined by the timing controller may be applied automatically in sequence to each of the devices. The sequence is started by a push button switch 38 which energizes a relay 53 closing (1) a retaining contact 58 in series with a "top" button switch 46, and (2) a contact 59 energizing the sequence controller element 65 whereby one or other of the coils 26-31 of blower contactors 18-23 is closed to prepare the circuit of a blower motor. An auxiliary contact on the blower contactor energizes the timing motor 36. The timing controller starts and makes in sequence connections (1) maintaining the circuit of motor 36 until the cycle is complete (2) energizing a "forward" contactor coil 24 to start the blower motor (3) closing a diverter circuit parallel with the timing motor armature through a resistance 92 by a contact 91 which is closed by the contactor coil 26-31 or by other means determining the speed of the timer for a portion of the cycle (4) preparing the circuit and the "reverse" contactor coil 25 (5) de-energizing the "forward" contactor, a back contact of which energizes the " reverse " contactor, simultaneously opening the armature diverter circuit (6) energizing the motor 37 of the selector controller 35 (7) deenergizing the motor 37 of the selector controller 35 (7) de-energizing the "reverse" contactor thus completing the cycle. The speed of the timer motor 36 during reverse movement of the blower may be accelerated by a field diverter resistance 106 through auxiliary contacts on the reversing and blower contactors. The timer motor is kept running until it reaches its initial position by a contact on the timer. The selector controller motor 37 is maintained operative until the next blower contactor has been energized by a contact 103 on the controller. The cycle will be repeated with successive blower motors until the sequence is complete since each blower contactor when energized from controller contact 65 re-energizes the timer motor through a contact such as 69. The sequence may be stopped automatically at the end of any cycle by an adjustable cam 116 or the selector controller 35, which operates a switch 49 in series with the relay coil 53 and may be restarted from this point by closing the push button switch 38. The controller 35 may be set manually to start the sequence with any blower. When a blower is moved inwards and outwards it may operate a switch 85 or a valve to maintain the power supply to the end of its outward travel and where a rotary blower has to stop at a given angular position it may operate a switch 97 or a valve whereby power is maintained on the blower until this position is reached. Auxiliary contacts 115 on the blower contactor may operate indicating lamps 114.