MetFab - Air Products Welder's Handbook - Flipbook - Page 17
Top Tip
Weld process gases containing
helium enhance heat transfer which
assists when welding metals with
high thermal conductivity such as
aluminium, copper and their alloys.
Power sources
for TIG welding
Power sources for use with TIG welding
can either be alternating current (AC) or
direct current (DC), both must be capable
of delivering a constant current at a
preset value.
Using a high frequency (HF) arc
starting device enables the arc to be
struck without the need to touch the
workpiece with the electrode.
One of the advantages of TIG is that
it allows you to weld a wide range of
materials. Modern power sources combine
constant current and constant voltage
characteristics and deliver excellent arc
stability. Machines ranging from
5A (micro-TIG) to over 500A are available.
Spark of
HF-discharge used
to ignite the arc.
Starter unit
Work
Diodes to prevent spark
of HF being fed into
power supply unit
Power
supply
unit
13
