GB905052A - Improvements in or relating to electric control devices - Google Patents

Abstract

905,052. Control of several motors; controllers. LANDIS & GYR A.G. July 14, 1960 [July 17, 1959], No. 24604/60. Class 38 (3). A control shaft 17, forming part of a maximum demand meter, is driven by a servomotor 3 through one revolution at a time. During each revolution, the shaft 17 changes over a switch 5 and returns it to its initial position, the shaft being coupled through reduction gearing 18 to a shaft 19 for actuating switch 6. The switch 5 may also be actuated manually by push-button 20, and a second servomotor, forming part of unit 2, may be associated with the first. When a switch 7 is actuated by a timer or remote control unit 23 to engage contact 13, both motors are energized through contacts 11, 9, and start together. A holding circuit is then completed through switch 5 which immediately engages contact 10. Switch 6 is subsequently engaged with contact 12 and remains in this position, for the rest of the cycle. At the end of the revolution of the control shaft 17, the switch 5 is re-engaged with contact 9 to de-energize the motor. The motor is re-started when a further control signal is applied to unit 23 so that switch 7 is re-engaged with contact 14. The push-buttons 20 afford separate control of one motor, without affecting the other. The switch 6 may comprise a rotatable contact-arm associated with semicircular contact segments. The control of the switch 5 is effected by a cam-plate of insulating material mounted loosely on shaft 17 and driven by a dog fixed to the shaft. The push-button has a thrust spring co-operating with an abutment surface on the cam-plate, Fig. 2 (not shown).