| 摘要 |
PURPOSE:To protect measuring instruments, cables, etc., in a voltage measuring circuit of the field circuit of a generator from a short circuit and burning failure, by a current detector which operates on said field circuit through a short circuit current limiting resistor. CONSTITUTION:Alternating power supplied from an excitor is given to a generator 5 through field circuit breakers 4 after being rectified by a thyristor rectifier 3 housed in an excitor switchboard 2. Voltage of the field circuit is indicated on a voltmeter 7 in a central controlling room through cables 6 and at the same time is given to a field voltage regulator 9 through cables 8 so that the regulator 9 controls an arc of the thyristor rectifier 3 with a signal 10 from the field voltage regulator 9 when it is necessary to keep the field voltage at a certain value. A field short circuit protecting unit 11, which consists of a current limitting resistor 12 and a current detector 13, and impedance of which is several hundred ohms, is connected in series with the voltmeter 7 and the field voltage regulator 9 in order to limit the large short circuit current of the field circuit. |
