Improvements in apparatus for driving and synchronising parallel-connected alternators

摘要

693,057. Fluid-pressure servomotor-control systems; maintaining speeds &c. HOBSON, Ltd., H. M., and SMITH. C. P. Oct. 24, 1951 [Jan. 19, 1951], No. 1536/51. Classes 69(ii) and 135 Apparatus for driving at constant speed and synchronizing a plurality of parallel-connected alternators, comprises one or more hydraulic motors for driving each alternator, each motor being supplied by one or more remotely located variable delivery pumps, one alternator and its associated motor or motors and pump or pumps being a master unit, and each other alternator and its associated motor or motors and pump or pumps being a slave unit. The apparatus is shown controlling a pair of alternators 10, 110, Fig. 1, in an aircraft. The master unit comprises the alternator 10, driven by a hydraulic motor 12 supplied with liquid from two pumps 13 drawing from a reservoir 14. The delivery pressure of the pumps is controlled by a signal pressure in a line 23 derived from the pump delivery line 22, through a governor 15 comprising a valve 17, Fig. 2, positioned by flyweights 16 on the motor shaft. Thus, an increase in speed increases the signal pressure to cause a decrease in the pump delivery pressure and vice versa. The slave unit comprises the alternator 110 driven by a hydraulic motor 112 supplied by pumps 113 drawing from a reservoir 114. The signal pressure in line 123 is derived from a device 26 comprising a piston valve 27, Fig. 3, centred in a housing by springs 29. The delivery pressure of pumps 13 acts through line 28 on the piston valve and the delivery pressure of pumps 113 acts thereon through line 122. The valve controls the application of the delivery pressure of pumps 113 to line 125 and thence line 123, and thus a variation in the delivery pressure of pumps 13 causes a corresponding change in the signal pressure in line 123 and hence in the delivery pressure of pumps 113 whereby the alternator of the slave unit is synchronized with that of the master unit. A governor 115 comprising a valve 117 is interposed between lines 125, 123 and movable by flyweights 116 on the shaft of motor 112. This valve controls the signal pressure in line 123 should the master unit cease to operate, in which case valve 27 will move to the left to close line 125. The valve 117 is set to control the slave unit at a slightly higher speed than the device 26. The pumps may be of the variable-stroke swashplate type or of the kind described in Specification 659,010.