Patent GB-130232-A (GB)
Title: Improvements in and relating to Systems of Electrical Distribution.
IPC: H02J1/16
Filed: 1918-10-30
Abstract: 130,232. British Thomson - Houston Co., (General Electric Co.). Oct. 30, 1918. Equalizing load on generator; regulation, automatic systems and apparatus for.-In electric distribution systems having fluctuating loads, such as rolling-mill or crane motors, an equalizer set is used consisting of a dynamo-electric machine connected across the mains and coupled to a flywheel, the control of the machine being made to depend on the load and on the current traversing the machine, so that excessive current cannot pass through it either when working as a motor or as a generator. The dynamo-electric machine 4 of the equalizing set is connected to the mains 1, 2 by the leads 7, 8, and on its armature shaft are the fly-wheel 5 and armature 11 of the exciter E for the field 6. In the leads 7, 8 are placed the series windings 15, 17 of two reverse-current relays, a shunt 19, starting resistance 51, and combined overload cut-out and circuit-closer 50. To start the set, assuming the generator G is running, the field 6 is first connected by the twoway switch K to the leads 7, 8 to bring the machine up to speed and then the field is connected to the exciter. A resistance 13 is ineluded in the field circuit of the exciter under control of a relay 14, which in turn is controlled by a vibratory regulator A. One of the contacts of this regulator is moved by a coil 24 placed across a shunt 3 in the mains. With the contacts closed, a circuit is completed through the lower part of the winding 40 of the relay 14, which thereby neutralizes the effect of the upper part of that winding, and as a consequence allows the contacts 41, 42 to remain closed and shortcircuit the resistance 13 in the exciter-field circuit. The winding 40 is energized by the exciter. During working the regulator A controls completely tne running of the machine 4 provided that the current traversing it either as a motor or as a generator does not exceed a certain amount. Assume that it is working as a motor, that is. that the load on the mains is so low that the generator G can fully supply it; the relay 17 will have its contacts closed and be inactive. The relay 15 may close its contacts as soon as the machine motors or when the current passing therethrough is excessive. When the contacts 30, 31 are closed, the contacts of a second vibratory regulator B are placed in shunt to the contacts of the regulator A; the controlling-winding 26 for the regulator B is placed across a shunt in the lead 8, so that when the motoring current tends to become high the regulator B modifies the action of the regulator A to increase the strength of the field 6, and prevent excessive rise of current. The contacts of the regulator B act on the windings 40 of the relay 14 in the same way as the regulator A. When the machine runs as a generator, the relay 15 opens its contacts and the relay 17 is also open either directly generating begins or when the current is at a certain value. Contacts of another vibratory regulator C are then put in series with the contacts of regulator A; the controlling-winding 28 of this regulator is, together with the winding 26 of the regulator B, placed across the shunt 19. The regulator C modifies the action of the regulator A to limit the current generated by the machine 4. The coils 25, 27 and 29 controlling contacts of the three regulators are connected to the exciter.