How do welding transformers work?
Welding transformers apply to the contact and arc elektroyosvarka. The short circuit of secondary winding of the transformer is the noryomalny operating mode at contact welding (at contact of elektyorod) and often arises at arc.
For restriction of currents of KZ welding transformers build with the big induced resistance and rather low power factor. Increase in induced resistance the obmoyotok of the welding transformer can be reached by either application of the speyotsialny design of windings, or inclusion of additional inductance in the chain secondary (or primary) the winding. Increase in induced resistances of windings in the transformer is reached by increase in flows the rasseyayoniya for what transformer winding places on different rods of the magnetic conductor or in different places on rod height.
Turning on of magnetic shunts in the magnetic conductor (fig. 1a) the rasseyayoniya and induced resistance of transformer winding also sharply increases flows. Transformers for contact welding do with the secondary winding consisting of one round on which tension usually does not exceed 14 Century. For regulation of the current proceeding through the welded part, primary winding of the welding transyoformator has several conclusions which switching allows to change number of rounds of the winding.
Now the welding transformers intended for arc electric welding have the widest circulation.
Such transforyomator build on the secondary voltage of 60-70 V (tension of ignition of the arch).
Feature of operation of these transformers is the intermittent duty of work with abrupt junctions from no-load operation to the short circuit, and back. Minor changes of current and considerable inductance in welding chains are necessary for steady and continuous burning of the arch.
For regulation of current in the welding chain consistently with secondary winding of the transformer vklyuyochat the inductive coil with the steel magnetic conductor (fig. 1b). Velichiyona of the welding current depends on diameter of the electrode and is regulated by the condensance of the inductive coil which depends on the size of air gap And. Increase in air gap in the magnetic conductor of the inductive coil causes reduction of its condensance owing to what current in the svayorochny chain raises. Sometimes inductive coils combine in the single whole with the welding transformer.Top