Patent GB-190425784-A (GB)
Title: Improvements in Means for Regulating Electric Circuits.
Inventor: LEITNER HENRY
Filed: 1904-11-26
Granted: 1905-11-23
Abstract: 25,784. Leitner, H., and Lucas, R. N. Nov. 26. Dynamos, regulating.- In a train-lighting &c. system, resistance is automatically cut out of the main lighting-circuit as the voltage of the batteries decreases, and the charging-dynamo is cut out of action, when the batteries are fully charged, by breaking or introducing a high resistance in series with its field winding, the dynamo being again introduced to charge the batteries when the voltage sinks to a predetermined value. The train-driven shunt or compound - wound generator a, Fig. 1, charges the accumulators b, which supply current to the banks of lamps c, c'. The arm g of a circular rheostat with fixed contacts e and two brushes j, j<1> is rigid with a wormwheel rotated by the worm i on the shaft of the motor M, which is fed from the accumulators. In parallel with the lamps and in series with the rheostat resistance is arranged a resistance and a potential regulator Vm, which may consist of a solenoid attracting a core q arranged to operate a spring-controlled pivoted horizontal bar r, one of the ends s, s<1> of which may dip into a mercury cup, thereby completing the circuit of the motor in such a way as to cause it to rotate in one direction or another according as the end s or the end s<1> dips into the mercury. When the lights are turned on and the dynamo is charging the accumulators, the arm g being in the position shown in Fig. 1, if the voltage rises above a predetermined point the core q is raised and the end s makes contact, operating the relay Sr, which actuates a switch, Fig. 2, so as to cause the motor to revolve in such a direction that the arm g is rotated clockwise, inserting resistance into the circuit of the solenoid, the pull of which is thereby weakened, the contact s broken, and the movement of the arm g stopped. If the voltage of the battery b sinks, the end s<1> makes contact and the motor is driven in the opposite direction, to cut rheostat resistance out of the lamp circuit until the contact s' is broken again and the motor stops. When the open-circuit voltage of the battery or of the generator has risen to a certain high predetermined point, the contact s is made, and the contact-arm is brought round clockwise to the extreme end of its travel, knocking the spring-controlled trigger - switch n into the position shown in dotted lines in Fig. 1, breaking the contact x, Fig. 2, stopping the motor, and allowing the contacts o, o, which were formerly held apart, to come together, short-circuiting the resistance Vr in series with the solenoid. The resistance Vr is also short-circuited when hand. switches are closed to feed the lamps c, c'. In this position of the switch n the whole of the resistance wire f<1> is introduced in series with the shunt wire winding of the generator by the opening of the contacts p, p, and the generator is practically without load. With the resistance Vr cut out of circuit the potential-controller acts with lower maximum and lower minimum voltage, and the motor M is not set iu motion until the voltage of the battery has dropped to a low point, thus preventing hunting. At this low voltage the contact s<1> is made, the rheostat arm moves counterclockwise, knocks the switch n to its original position, and cuts out the resistance, and in the extreme position the arm opens the contact y, Fig. 2, and stops the motor. Fig. 2 shows the invention diagrammatically as applied to a system in which a differentially-wound main generator G is arranged in conjunction with a subsidiary dynamo D which weakens the field of the former as the speed of driving increases. Regulating- resistances Ri of positive temperature coefficient and Rh of negative coefficient, and an automatic mercury switch with windings As<1>, As', As' for connecting the batteries with the generator, are employed. Reference is made to Specifications Nos. 16,492 and 25,216, A.D. 1902, [Abridgment Class Electricity, Regulating &c].