4
Connection and installation
Page 27
Stud welding unit
operating manual
Date:
July 2021
ALPHA 850
07.2021 / EN
Rev.:
A
Arc blow effect
“Blow effect” means lateral deflection of the arc from the central position. Based on
the cause, a distinction is made between the following blow effects:
•
Thermal blow effect:
Deflection of the arc through expansion and
turbulence of heated gases in the arc combustion
chamber.
•
Magnetic blow effect:
Deflection of the arc through the influence
of magnetic or electromagnetic fields.
The possibilities for reducing thermal blow effect are limited. They are limited to the
most exact possible centring of the stud and stud holder.
To reduce the effects of magnetic blow effect, several corrective measures are
available, some of which are shown below.
To favourably influence the arc, the
earth clamps must be arranged as
symmetrically as possible at the
welding location.
Influences on the arc by the
welding cable can largely be
prevented by turning the welding
gun 90°.
With a one-sided earth clamp, the arc
blows away from the clamp. This
situation can be eliminated with
additional metal plates.
When welding profiles, the arc blow can
be reduced by placement of the earth
clamp and additional metal plates.
Note:
The polarity in the illustration relates to ferromagnetic materials. When
welding aluminium, the opposite polarity must be ensured!
