Welding of parcels reduces losses due to magnetic dispersion, vibrating and noise effects - as opposed to mechanical fixing. At present welding of transformers, engines and electric motors (more exactly - their steel magnetic cores, or parcels) became much easier with plasma arc usage.

Afraiding of overheating of coils which were situated inside of closed cores, some customers tried to use for these purposes laser welding .However they did not succeed because of difficulties to get the complete seam with a good appearance. Since each plate is covered by a special, very thin layer of isolation, laser beam melted separately an edge of every plate, but did not connect them together by a normal seam.To use electron beam was neither possible because of intensive evaporation of the mentioned isolating layer.During first attempts of microplasma welding we had problems, when using argon-hydrogen mixtures as a shielding gas, which gave sometimes the porosity.The power of microplasma set (up to 30 A) was also not enough.Using apparatus with two-three times higher power, CO2 as a shielding gas and determining the optimal welding parameters (including the high welding speed) we have reached excellent results.The melting depth of parcels welds became up to some millimeters, seams had smooth, shining surfaces, and transformers had minimum heating. Such processes were successfully approved at the some former USSR plants which make video- and electro- radio technics.At the beginning we had to connect in parallel two microplasma sets (on 30 A each other). Now, having one of the cheap, safe, and simple sets on 100A , we can produce the above mentioned goods very easily (please, see the picture 1. SOME GOODS WELDED BY PLASMA WITHOUT POST CLEANING - MAGNETIC CORE from the www.pogrebis-temp.com/goods.html).

Before building the above mentioned set, when the blocked plasma set was brought to life, it was suggested to us to use this set at the "Richmond Amcor"company.It was a manufacturer of small electric motors, and there are popular three typical diameters of motor stators: 90, 110 and 140 mm. We visited this company in Jerusalem and wrote the Proposal "Enlargement of motor stators productivity and quality by using plasma welding in CO2". We saw Italian equipment which used the argon (TIG) welding and gave not good quality of seams.

In our Proposal it was written about advantages of proposed plasma welding:

  1. Cheap shielding gas:CO2 instead of argon
  2. High welding speed
  3. High stability of process and quality of welds that have narrower heating zone
  4. Absence of the problem of welding arc ignition
  5. Saving of metal (rings which are necessary at the beginning and at the end of each weld for every stator during TIG welding)

None the less, we are sure that realization of our ideas and of new sets usage for magnetic cores welding is very perspective. Especially - because the new set has some additional features which allow to blow across the channel of the plasma forming nozzle that may be sometimes littered by products of above mentined isolating layers evaporation (layers are placed between plates from the steel, which includes silicon and can be also partly evaporated) during welding.

The new simple sets give possibility to braze collector connections of some electric engines armature. For big engines it is preferable to use combined welding-brazing methods. As opposed to the usual gas flame brazing, new technologies can give much better quality and absence of post-cleaning.

That is why the new sets may be ordered by producers of small transformers, stators and rotors of electric machines in all of the world. Such users may be many tens and even hundreds.

Another possible usage of our new sets may be spot plasma welder.

Bodies of small electric engines, assembled by plasma spot welding.
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