| 摘要 |
1,227,845. Control of several motors. GENERAL ELECTRIC CO. 29 March, 1968 [19 April, 1967], No. 15313/68. Heading H2J. [Also in Division G4] The invention relates to the control of rolling mills and is concerned with changing the speed of the mill as a whole without upsetting the speed ratios between the various motors. Each pair of rollers is driven by a motor (DM, DM2, Fig. 1, not shown) under the control of a device (SC) which regulates the speed of the motor to a value proportional to the pulse rate of an applied pulse train. The individual pulse trains are derived by division, in a pulse multiplier 14, from a master pulse generator 13, 22. The ratio of input to output pulses of each multiplier is set by a respective speed reference register 16. The pulse generator comprises an oscillator 22 and a series of bi-stable dividers 61-72; the register 16 comprises a similar set of dividers 81-92. The pulse multiplier 14 has a plurality of AND gates 101-112 arranged to pass pulses from the dividers 61-72 when the respective stage 81-92 of the register carries a logic 1. To increase the speed of a motor the count in its register must be increased to increase the proportion of pulses passed by the pulse multiplier 14. To increase the speeds of all the motors in the desired ratio each register 16 is fed with the output pulses of its respective pulse multiplier 14 by way of AND gate 15, under the control of a common controller 18. The speed of a particular motor can also be altered by its individual controller 17 which feeds pulses at constant frequency (from one of the dividers 61-72) by AND gate 47 to the register 16. Each register 16 is provided with an AND gate 51 which gives an output when the register is full and an AND gate 55 which gives an output when the count in the register reaches a value representing the minimum speed for the respective motor. An output from any of the gates 51, 55 causes all AND gates 25, 27, 42, 44 to be opened so that no motor may be run outside its desired speed range. |
