GB246133A - Improvements in or relating to rotary electric transformers for coupling two alternating current networks - Google Patents

Abstract

246,133. Siemens - Schuckertwerke Ges. Jan. 17, 1925, [Convention date]. Equalizing load in systems depending on two or more machines.-For coupling two alternating-current circuits of fluctuating or different frequencies and effecting an interchange of power between them, a converter is employed consisting of two machines of asynchronous type provided with a flywheel mass and with regulating devices for altering the loadspeed characteristics of the machines. The set has the property of changing its speed without affecting the two circuit frequencies, and may consist cf two asynchronous machines cascaded with commutator machines, in which case regulation is effected by controlling the secondary voltage which is introduced into the slip circuit by the commutator machine. Alternatively, two three-phase shunt commutator motors may be employed with regulation by brush-shifting. Fig. 1 shows a form in which the circuits 1, 2 are connected by a converter comprising, two 3-phase shunt machines 3, 4 with a flywheel 5 on their common shaft. By regulating one machine as a motor subsynchronously and the other as a generator hypersynchronously, power may be transferred from one circuit to the other. With a sudden power demand, on the circuit 2, for instance, the machine is regulated to act as a generator, putting a greater load on the converter shaft and bringing, the flywheel into action to give a buffering action. Tirrill or other quickaction regulators may be used to regutate the machines automatically and bring about the buffering action at prescribed load conditions. When the generator element does not work in parallel with other machines, it may be regulated in accordance with the frequency, voltage, or other condition of the. supply or consumption circuit by means of a frequency relay or other device; when it works in parallel with other sources, it may be automatically regulated in accordance with the whole or a part of the load current.