| 摘要 |
606,498. Automatic control systems for A.C. generators. JONES, R. C., PAYNE, N. H., and STREETE, R. H. Dec. 16, 1943, No. 21158. [Class 38 (iv)] Voltage.-In order that the output voltage of an alternator, such as one driven by an aircraft engine, may remain constant with rise of speed and frequency above a unusual value and may fall with failing speed, the operating coil of the voltage regulator is supplied through a suitably adjusted frequency-responsive network. Thus, the coil 18 of a carbon pile regulator 16 for the field of an exciter 13 is connected through a rectifier 19 to a potentiometer 29 connected to the output terminals of an A.C. bridge, the input terminals of which are connected across two of the three-phase output conductors of the alternator 10. The bridge comprises inductances 23, 25 and condensers 24, 26 with a resistance 40 and is nearly in balance at normal frequency. The electrical quantities are chosen so that an increase or decrease in frequency causes an increase in the voltage applied to the potentiometer and the resulting alternator voltage changes with frequency as shown in Fig. 3, where the normal frequency is 250 cycles and the curve 39 indicates the change of voltage with constant excitation. At speeds above normal, the alternator 'voltage is substantially constant as at 37 and at sub-normal speeds the voltage falls according to the curve 36, 38. The slope of the part 38 is adjusted so that the electrical load will fall at substantially the same rates as the power output of the engine. The regulator has a stabilizing coil 17 and an opposed compensating coil 17a. |
