| 摘要 |
1,228,748. Welding generators; welding systems. BULPITT & SONS Ltd. 1 Oct., 1968 [4 Oct., 1967], No. 45092/67. Headings H2A and H2H. In an electric arc welding apparatus comprising a D.C. generator 10 having compound wound excitation with interpoles 16 and brushgear which is angularly movable within a range e.g. 13 degrees to any position from a geometric neutral axis, main poles 39 each have a trailing tip 41 extending further from the core axis in the direction of armature rotation than does the leading tip 40 extend in the opposite direction. The extent is such as to saturate in order to limit the maximum short-circuit current of the generator. The generator armature 10a is connected to electrode terminals 13, 14 via shunt and series field windings 11, 12, interpole windings 17, a stabilizing choke 15, shunt field regulating resistors 18, 19, and a shunt field current limiting resistance 20. In the embodiment shown an I.C. engine or an electric motor drives both the generator 10 and an auxiliary generator 21 which supplies the shunt field winding 11 via a polarity reversing switch 26 having auxiliary contacts 28, 30 to render effective the resistance 20 during operation of the switch. The output polarity is indicated visually by either a centre-zero voltmeter or neon lamps 36, 37 operated by relay 31 whose coil is polarized by a blocking diode 32. |
