| 摘要 |
890,620. Voltage control systems. ALLMANNA SVENSKA ELEKTRISKA A.B. Dec. 4, 1959 [Dec. 6, 1958], No. 41219/59. Class 38 (4). A circuit for preventing the excitation of a synchronous generator 1, 2 falling below a staple value comprises an exciter 3 whose shunt field winding 4 is in series opposition with a generator armature 5 energized by two opposing field windings 6, 7, winding 7 being supplied through a rectifier 8 and transductor 9, 11, 12 from a potential transformer 10 connected across supply lines R, T. Another rectifier 16 supplies the transductor control winding 12. The circuit described so far reduces the winding 2 current for an increase in R, T voltage. The transductor control winding 12 is alternatively fed by a rectifier 17 controlled by a self-excited transductor 35 whose control winding is fed by voltages derived from voltage and current transformer 18, 21 and passed through a phasesensitive circuit arranged so that the current in winding 2 is adjusted to maintain the induced generator voltage at a constant phase angle, 90 degrees being proposed in the embodiment described. The transductor winding 12 is fed, by means of rectifiers 13, 14, from whichever rectifier 16 or 17 is developing the lower voltage, thus maintaining the generator voltage above the unstable limit. |
