Tweco 550i Transmig - Manual (Page 27)

TRANSMIG 350i, 450i, 550i
Manual 0-5205 3-7 INSTALLATION, OPERATION AND SETUP
8. Process Selection Button
The process selection control is used to select the desired welding mode. Three modes are available,
GMAW/FCAW (MIG), GTAW (Lift TIG) and MMAW (Stick) and Gouging (Transmig 550i only) modes. Refer
to section 3.15 or 3.16 for FCAW/GMAW (MIG) set up details, section 3.17 for GTAW (Lift TIG) set-up
details or section 3.18 for MMAW (stick) set-up details.
Note that when the unit 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 unit
and mistakenly be in contact with the work piece during power up.
9. Trigger Mode Control Button (MIG and LIFT TIG Mode only) (Only applicable to 10 pin mode)
Note that this feature on the power source only applies to devices connected to the 10 pin control socket.
In the case of wirefeeders connected to the 19 pin socket the function is controlled from that independant
wirefeeder only.
The trigger mode control is used to switch the functionality of the of the torch trigger between 2T (normal),
4T (latch mode) and SPOT (spot mode)
2T Normal Mode
In this mode, the torch trigger must remain depressed for the welding output to be active. Press and hold
the torch trigger to activate the power source (weld). Release the torch 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 torch trigger and the output will remain active. To deactivate the power
source, the trigger switch must again be depressed and realised, thus eliminating the need for the operator
to hold the torch trigger.
Note that when operating in GTAW (LIFT TIG mode), the power source will remain activated until the
selected down slope time has elapsed (refer Item 10).
SPOT Mode
This mode of welding is similar to 2T mode, except the welding output will be active only for a preset
amount of time. This mainly used for tacking at the start of a job setup. Press and hold the torch trigger
to activate the power source (weld). After the SPOT time has elapsed and welding output has ceased,
release the torch trigger switch.
10. VRD ON/OFF Indicator Lights
A VRD (voltage reduction device) is a hazard reducing device designed to reduce electric shock hazards
present on the output of welding power source when operating in MMAW (stick) mode. Note that
the presence of VRD should not be used as a substitute for the use of appropriate safety practices as
indicated in section one of this manual.
Both the green and red indicator lights only operate in MMAW (stick) mode.
The green VRD ON light illuminates (red light is off) when the VRD is active. Under this condition the
open circuit voltage of the unit is limited to below 35V DC, thus reducing the potential of serious electric
shock (such as when changing electrodes).
The red VRD OFF light illuminates (green light is off) when the VRD is inactive. Under this condition the
output voltage of the unit will be at welding potential which in some cases may exceed 35V DC.
The VRD incorporated within the TRANSMIG 350i, 450i and 550i is fully standards compliant to AS
60974.1 / IEC 60974-1.