DD126251B1 - Kernel transformer with distributed primary winding - Google Patents

Description

Title of the invention:

"Core version with distributed primary winding"

Field of application of the invention:

The invention relates to a transformer core version with distributed primary winding, in particular for the arc welding technique in which a part of the primary winding and the secondary winding are arranged together on a leg and designed as a cylinder winding.

Characteristic of the known technical solutions:

It is known to apply the principle of the redistribution of turns to adjust the voltage characteristic ika. When using this setting principle for welding transformers small and medium power, the switching of primary-side windings is preferred because of the smaller currents. In this case, it is possible to utilize the scattering minimum occurring in the case of a two-ply embodiment of a main winding. For example, in the embodiment customary for small welding transformers, the scattering minimum occurs when about 70 to 80% of the switched-in primary windings are arranged on the same leg as the secondary winding. As a result, approximately 70 to 80 % of the turns must be redistributed at a required setting range of the welding current of 2: 1 to 3: 1.

To avoid this ITachteiles already a special arrangement (V / P H 01 f / 190 961) has been proposed. Here are one

Part of the primary winding and the secondary winding arranged on a common leg and designed as a low-dispersion cylinder winding. For this arrangement, the redistribution of approximately 40 to 50 % of the primary windings is sufficient if the welding set point is placed in the region of the strongest dependency of the welding current on the ratio of the number of turns of the coils of the split winding.

A disadvantage of this arrangement, however, is that the primary current of the ratio of the number of turns of the portion of the primary winding _{# is} located on a leg together with the secondary winding, the number of turns of the total switched primary turns number depends. At certain values of the aforementioned turns ratio and with increasing load, the primary current increases very much beyond the gear ratio.

In unfavorable circumstances, this can result in a primary current which reaches twice the value resulting from the transmission ratio.

The increase of the Primärstro nies occurs all the more, the closer the coupling between the secondary winding and the arranged together with her on a leg part of the primary winding is. In the unfavorable Pail described above, the proposed low-mass arrangement can only be used in conjunction with complex and expensive reactive current compensation devices.

Goal of the invention;

The aim of the invention is to provide a core transformer with a distributed primary winding in which the manufacturing and operating costs are reduced while maintaining the small total mass of the transformer including the reactive current compensation device.

Explanation of the essence of the invention:

The object of the invention is to modify the known transformers in such a way that, while maintaining the

The number of redistributable turns and the welding-technologically favorable values of the secondary no-load voltage have a smaller primary current which is independent of the turns ratio of the windings to be redistributed and which is determined by the secondary current only under load, thereby reducing the expense for the reactive current compensation device.

It has been found that a greater saturation of the laminated core, which is the cause of the increase in the primary current and the associated adverse effects, only occurs in the leg, in which a part of the primary winding is arranged alone ·

According to the invention, therefore, the object is achieved in that the leg, on which a portion of the primary winding is arranged alone, with an up to 40 to 50 % enlarged cross-section relative to the cross section of the rest of the laminated core is executed.

Since the primary winding is arranged distributed over two legs, the mains voltage at idle is divided according to the Windungszahlverhältnis on the two coils. When loading the transformer, it comes through the tighter coupling to the turns of the primary winding, which are arranged with the secondary winding on a leg, a voltage drop. As a result, the voltage at the part of the primary winding, which is arranged on the other leg alone increases and leads in this leg to a greater Aussättigung and thus to an increased magnetization demand. Due to the reactive current required for this, there is a disproportionate increase in the mains current in relation to the secondary current.

Since the stronger saturation of the laminated core occurs only in one leg, it is necessary to reinforce only this leg, while the other leg and the two yokes can be performed with reduced cross-section.

This makes it possible in the inventive design, an optimal ratio of winding mass and laminated core

To realize mass and thus a transformer with a small mass, while maintaining the welding technology favorable values of welding current and open circuit voltage build.

Embodiment:

The invention will be explained in more detail below with reference to an exemplary embodiment. The accompanying drawing shows a schematic representation of the front view of a single-strand small welded transformer in core design. The laminated core consists of yokes 1; 2 and thighs 3; 4 · Secondary winding 5 and a coil 6 of the split primary winding are performed together on the leg 3 as low-dispersion cylinder windings. A second coil 7 of the split primary winding is arranged in loose coupling to the secondary winding on the opposite leg 4. The adjustment of the current voltage characteristics is carried out by stepwise redistribution of turns of the coil 6; 7, which are each connected in series. The leg 4 has a cross section about 50 % larger than the opposite leg 3 and the two yokes 1; 2. By this uneven execution of the two legs 3; 4 it is possible to ensure favorable values for the welding current and the secondary open-circuit voltage at low mains current consumption and low mass in all stages.

Claims (1)

Invention claim: A transformer with a distributed primary winding, in particular for the arc welding technique, in which a part of the primary winding and the secondary winding are arranged together on a leg and designed as a cylindrical winding, characterized in that the leg is arranged on a part of the primary winding alone, with a Up to 40 to 50 % enlarged cross-section compared to the cross section of the rest of the laminated core is executed. For this 1 sheet drawings