Tweco 181i Thermal Arc Fabricator - Manual (Page 41)

Fabricator 181i
Manual 0-51 91 3-11 INSTALLATION, OPERATION AND SETUP
2T (Normal Mode)
In this mode, the MIG or TIG Trigger Switch must remain depressed for the welding output to be active. Press
and hold the MIG or TIG Trigger Switch to activate the Power Source (weld). Release the MIG or TIG Trigger
Switch to cease welding.
4T (Latch Mode)
This mode of welding is mainly used for long welding runs to reduce operator fatigue. In this mode the operator
can press and release the MIG or TIG Trigger Switch and the output will remain active. To deactivate the Power
Source, the trigger switch must again be depressed and released, thus eliminating the need for the operator
to hold the MIG or TIG Trigger Switch
Note that when operating in LIFT TIG mode, the Power Source will remain activated until the selected Downslope
time has elapsed (refer Control No. 9).
12. Process Selection Control
The process selection control is used to select the desired welding mode. Three modes are available, MIG,
LIFT TIG and STICK modes. Refer to section 3.15 or 3.16 for MIG (GMAW/FCAW) set up details, section 3.17
for LIFT TIG (GTAW) set-up details or section 3.18 for STICK (SMAW) set-up details.
Note that when the Power Source is powered OFF the mode selection control will automatically default to MIG
mode. This is necessary so as to prevent inadvertent arcing should an electrode holder be connected to the
Power Source and mistakenly be in contact with the work piece during power up.
13. Digital Voltage Meter (Right Digital Display)
The digital voltage meter is used to display the both the preview voltage (MIG mode only) and actual output
voltage (all modes) of the Power Source.
At times of non-welding, the voltage meter will display a preview value in MIG mode. This value can be
adjusted by varying the multifunction control knob (Control No. 9). Note that in STICK and LIFT TIG modes,
the voltage meter will not preview welding voltage but will display Open Circuit Voltage in STICK mode and
0V in LIFT TIG mode.
When welding, the voltage meter will display actual welding voltage in all modes.
At the completion of welding, the digital voltage meter will hold the last recorded voltage value for a period of
approximately 10 seconds in all modes. The voltage meter will hold the value until; (1) any of the front panel
controls are adjusted in which case the Power Source will revert to preview mode, (2) welding is recommenced,
in which case actual welding amperage will be displayed, or (3) a period of 10 seconds elapses following the
completion of welding in which case the Power Source will return to preview mode.
NOTE
The preview functionality provided on this power source is intended to act as a guide only. Some
differences may be observed between preview values and actual welding values due to factors including
the mode of welding, differences in consumables/gas mixtures, individual welding techniques and the
transfer mode of the welding arc (ie dip versus spray transfer). Where exact settings are required (in
the case of procedural work), it is recommended that alternate measurement methods be utilized to
ensure output values are accurate.
14. Thermal Overload Indicator
This welding Power Source is protected by a self resetting thermostat. The indicator will illuminate if the duty
cycle of the Power Source has been exceeded. Should the thermal overload indicator illuminate the output
of the Power Source will be disabled. Once the Power Source cools down this light will go OFF and the over
temperature condition will automatically reset. Note that the power switch should remain in the on position
such that the fan continues to operate thus allowing the Power Source to cool sufficiently. Do not switch the
Power Source OFF should a thermal overload condition be present.