| 摘要 |
984,420. Synchronizing arrangements. MASCHINENFABRIK OERLIKON. March 10, 1961 [March 19, 1960], No.8911/61. Headings H2H and H2J. A circuit for applying an increased excitation current to a synchronous machine when it falls out of step comprises a resistor 9 in the excitation circuit the voltage across which is compared with a rectified fraction of the stator voltage from a potentiometer 6 through a relay winding 7a. If the machine slips a pole a voltage is induced in the field windings 2 opposite to that provided by the exciter 9 causing the current in resistor 9 to reverse hence causing relay 7 to operate and be held by winding 7b and contacts 7c. Further contacts 7d shunt a resistor h increasing the reference voltage to a regulator r, thus increasing the output to the exciter field winding b which returns the current in field winding 2 to its correct direction and causes the machine to slip back into step. The current in resistor 9 returning to its normal direction causes the relay 7 to deenergize. In an alternative arrangement, the relay 7 is replaced by a feed-back amplifier. |
