ESAB Heliarc 281iAC/DC, Руководство по эксплуатации

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26
section 5 operation
26
SECTION 5 OPERATION
OPTIMIZING TIG WELDING PERFORMANCE (con't.)
3. Maximum Current Ratings for Tungsten Electrodes
4. AC GTAW ( TIG ) Welding Using FC-5 C Foot Control
Unlike other AC TIG equipments the Heliarc AC/DC 281i, 283i and 353i do not use continuous HF to maintain the
AC TIG arc. Once the arc is struck the HF generator is turned off and will not re-energi z e unless the arc voltage
rises to above 40V or until the torch switch/foot control is reoperated . This feature means that the likelihood of
electrical interference from the welding equipment is greatly reduced.
When using a large and cold tungsten the very low starting current that would normally occur when using a
foot control can on occasion result in poor arc stability until the current is raised to a reasonable level and the
tungsten is hot. To prevent this the power source has an "A
min
" control enabling the minimum current as set by
the remote foot control to be independently preset, see CONTROLS & OPERATION section 2. Recommended
minimum AC current settings, according to tungsten diameter, are as follows:
1/16" ( 1.6mm ) 10A
3/32" ( 2.4 mm) 20A
1/8" ( 3.2 ) 30A
If at the end of welding it is required to slope out the current below the level set by the "A
min
" control, a short final
slope-out time can be set using the T2 up/down keys, see CONTROLS & OPERATION section 6, usually around
1 second is adequate. This will continue the slope down after the pedal has been fully released filling in any
residual crater.
1 /1 6 3/32" 1/8"
DC 150A 2 40A 380A
AC Balanced 60A 1 00A 1 50A