©
COPYRIGHT 1998 THE ESAB GROUP, INC. LESSON
II This rapid
current rise can be by
using a device called an (sometimes
called a stabilizer) output
circuit of the welder. An
merely an iron
core wound
turns of heavy wire. It does
current
flow, but it acts somewhat
like a fly wheel or damper
by retarding the rate of rise
as shown by the solid line.
By preventing the rapid
current rise, the arc becomes
smoother, spatter
is reduced, and bead
shape and appearance
are improved.
Because the inductor influences the time function, its design determines
arc on-off time,
and short-circuit frequency. Some power sources have a selector that can
switch in several
different inductance values to finely tune the arc. 2.4.4.4
Welding power sources designed for
gas metal arc welding have a 115 volt outlet to provide
power to operate the wire feeder. They also have a receptacle to receive
the electrical power
required to close the main contactor in the power source, which turns on the welding
power to the welding gun when the gun
trigger is actuated. 2.4.4.5
Additional advancements in equipment
technology have introduced many new models.
Inverters, as well as microprocessor controls, have created the greatest
attention. In addition,
multipurpose machines have provided the user with greater flexibility with a variety
of capabilities.
2.4.4.6 Global
competition will continue to have a profound influence on future
advancements in arc welding equipment.
As energy prices rise, greater demands for more efficient
equipment will follow. 2.4.5
Wire
Feeder -
When welding with a constant voltage power source, as is the case
in most gas metal arc welding applications,
the prime function of the wire feeder is to deliver the
welding wire to the arc at a very constant speed. Since the wire feed speed
determines the
amperage, and the amperage determines the amount of heat at the arc, inconsistent
wire feed speed
will produce welds of varying penetration and bead width. Advanced electronics
FIGURE 14 TIME
- MILLISECONDS EFFECT
OF INDUCTANCE ON CURRENT RISE 400
AMPS WITHOUT INDUCTANCE
WITH INDUCTANCE
150 AMPS
