| 摘要 |
999,141. Dynamo-electric machines. SIEMENS-SCHUCKERTWERKE A.G. March 30, 1962 [March 30, 1961], No. 12463/62. Heading H2A. An installation which includes an electrical machine 1, e.g. synchronous generator, in whose field winding circuit is an exciter rectifier 3, and an alternating voltage source, is provided with a de-exciting arrangement comprising connected across the field winding 2 at least two parallel paths 6, each including a rectifier 9 in series with a controllable fourlayer semi-conductor device 8 whose breakdown voltage is above the voltage normally applied to the field winding, means for connecting the source to the connecting points between the rectifiers 9 and devices 8, and means, not shown), for rendering the devices 8 conductive. To de-excite the generator switches 10 forming the connecting means are closed and a switch 12 is opened whereupon the paths 6 provide a D.C. voltage opposing that of the rectifier 3 which if the latter can act a invertor remains operative until field current reversal, but if not, is rendered inoperative by opening switches 13. A voltage transformer 5 and regulator 4 may regulate the rectifier 3 which, with the paths 6, may be positioned in the generator rotor. The source is either a constant-voltage permanent magnet generator 14 coupled to the generator 1 or, not shown, a self-excitation circuit of output current- and voltage-dependent transformers. High voltages across the field winding are prevented by condensers, and breakdown of the devices 8. |
