| 摘要 |
1,242,699. Automatic speed control. MITSUBISHI JUKOGYO K.K. Oct. 14, 1968 [Oct. 14, 1967; Oct. 30, 1967], No.48646/68. Heading G3R. In order to retroactively control the speed of a rotating machine 19 over a wide range, a special tachometer generator is employed. The latter employs a rotatable permanent or electromagnet 11 and a rotatable annulus 12 carrying a pick up coil 13. One of these is coupled to the machine 19 and the other driven by a motor M. When the machine 19 is required to run at its rated speed the annulus 12 is stationary and the system acts like a conventional tachogenerator system the output frequency of coil 13 being converted to a voltage in discriminator 30 and compared with a reference 32 to control a valve 20 adjusting the speed of the machine. The reference 32 is normally fixed but a small variation in speed can be provided by altering the reference. When, however, it is required that the machine rotate at a speed well removed from its rated speed the annulus 12 is rotated at a speed corresponding to the difference between the rated and derived speed so that the output frequency of coil 13 is proportional to the difference between the speeds of motor 14 and machine 19 and valve 20 adjusts the speed to the new desired speed (the reference 32 still being the rated speed). The speed of electric motor 14 is controlled by a further loop, including tachogenerator 15, according to a speed setting device 16. |
