SU791486A1 - Apparatus for electric arc welding by alternative current - Google Patents

Description

The main winding of the transformer and the coils 4 and 5 of the bifillary winding are connected in series. The no-load voltage at these moments is determined by the resulting turns of the main winding 2 of the transformer, opposite to this winding of the turned on coil 4 and according to the winding 2 of the turned on coil 5 of the bifilary winding. In this case, the idling voltage is equal to

Ua-wi.

Ml / i / 5, - 4- "/ s

where (Ji is the primary voltage

transformer; Wj is the number of turns of the transformer primary winding; W4, W5 - the number of turns additional

windings.

As can be seen from the formula, the open circuit voltage with closed thyristors can be increased by increasing the number of turns of the coil W4.

The magnitude of the maximum current with open thyristors 6 and 7 does not depend on the bifillary winding and is determined by the inductive resistance of the main winding of the supply transformer 1. The no-load voltage in this case is determined by the turns of the primary winding 2. The inductive resistance required to obtain a current limit It is provided by scattering currents, which are partly closed along the iron of the magnetic core of the supply transformer, partly through the air. The magnitude of the inductive resistance of the bifillary scattering winding is calculated from the condition of providing the specified value of the lower limit current of the transformer. The wire cross section of the bifillary winding is selected according to the value of the minimum current of the device.

Intermediate values of average current and no-load voltage are determined by the open angle of thyristors 6 and 7 and are summed up from the values of current and voltage of transformer 1 obtained at the moments when thyristors 6 and 7 are closed and at the moments when these thyristors are in conductive condition.

Use in the proposed device for arc welding on an alternating current of a new element - a bifilar scattering winding consisting of two parts located on opposite rods of the transformer magnetic circuit with equal or different number of turns connected oppositely in series with the primary winding transformer and shunted two anti-parallel thyristors, reduces the complexity and simplifies the manufacturing technology of the device, to save The use of active materials (mainly due to the use of a supply transformer RM), as well as using a bifillary winding with a different number of turns, improve the welding quality by increasing the no-load voltage at low currents or with the same welding quality to reduce the rated rated power of the supply transformer.

The proposed device was tested in operation and showed good rezug.ty.

Claims (2)

1. An alternating current electric arc welding device containing a welding transformer, in series with one of the windings of which an additional winding is included, shunted counter-parallel to the connected thyristors, characterized in that, in order to simplify the design of the device by eliminating droplets and simultaneously using the device for manual arc welding, the additional winding is made in the form of two bifil-wound coils located on opposite rods of the magnetic circuit of the welding tube ansformatora, wherein the coils are connected in anti-parallel with each other. 2. The device according to claim 1, wherein the coils are made with a different number of turns, and the coil, which is connected in opposite direction with the winding of the welding transformer, is made with a large number of turns. Sources of information taken into account in the examination 1. USSR author's certificate No. 397286, cl. 23 K 9/00, 1971. fuz.1 t S