Improvements in Apparatus for use in Welding Railway Rail Joints by Electricity

15,831. Kleinschmidt, H. F. A. July 17. Welding; working by electricity.-An apparatus for electrically welding rail joints is carried by one or more cars running on the rails to be welded, and takes its current from the line conductor. Fig. 1 shows a diagrammatic view of the apparatus arranged to compensate for fluctuations in the line conductor to preserve a substantiallyconstant potential difference between the welding-terminals 38, 39. The current from the conductor 1 is divided to pass through the controller 4 of of the motor 5 for driving the car, and through the shunt and series windings 9, 10 of a rotary converter to convert the direct into an alternating current. The series circuit is provided with an ammeter 23, and a starting-switch 7, 8, while the shunt circuit has a switch 15 and rheostat 20. By opening the switch 15 and closing a switch 17, the shunt 9 is placed in circuit with a directcurrent exciter 14 driven from the converter and having series and shunt windings 12, 13. The primary coil 42 of a transformer 40 is connected to the rings 36, 37 of the rotary converter, and the secondary coil 43 carries the welding-terminals. The voltage of the primary circuit is regulated by means of two coils 49, 50 connected together and provided with a reversing-switch 51 by which the voltage may be raised or lowered, and with a dial switch 52 by which the amount of alteration may be varied by varying the length of the coil 49 through which the current passes. A switch 44 in the primary circuit is provided with an induction coil 45 having a movable core 46 with a flexible connection to the movable member of the switch. Springs 48 support the movable member and the plunger, the inductive effect of the coil being decreased or increased by raising or lowering the plunger. When the speed of the rotary converter exceeds a predetermined limit, a circuit is completed between stationary rings 29, 30 by centrifugally-acting arms on the armature shaft under the control of springs, the tension of which can be adjusted. The completion of the circuit breaks the main circuit at 26. In starting the apparatus, the starting-switch is gradually closed, the switch 15 being closed. When a volt-meter 21 shows a zero reading, the switch 15 is opened and the switch 17 closed, the voltage of the circuit 42 being then regulated till a volt-meter 22 shows the desired reading.