Tweco 170i Transarc - Manual (Page 28)

TRANSARC 170i
INSTALLATION, OPERATION AND SETUP 3-10 Manual 0-5281
A-11724
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 released, thus eliminating the need for the operator
to hold the torch trigger.
Note that when operating in GTAW (TIG mode), the power source will remain activated until the selected
downslope time has elapsed.
A-11725
STICK Dead Man Switch Mode (Transarc 170i Mines Spec Model)
A special trigger mode called “Dead Man Switch” mode is available on the 170i when welding with STICK
electrodes. In this mode, there will be no output voltage at all from the Power Source until the trigger is
pressed. This provides the greatest level of safety for the operator, and is mandatory on some work sites.
While the Dead Man Switch function greatly increases operator safety, standard welding safety procedures
should still be followed.
When the trigger is pressed, the VRD voltage is activated and the user can start welding as normal. For
extra safety, if welding has not commenced within 3 seconds after the trigger is pressed, the Power Source
will turn off the VRD, and the trigger must be released & pressed again to start welding.
If the trigger is released during welding, all welding power is shut off within the time limits of normal
VRD operation.
A special STICK electrode holder is required for use with a Power Source fitted with a Trigger Switch.
This electrode holder has a trigger switch attached to it, and a control cable that connects to the remote
control socket of the Power Source. The 170i Mine Spec plant comes standard with one of these special
electrode holders fitted with an integrated trigger switch.
The Dead Man Switch function is active in both 2T and 4T STICK mode.
Welding with the Dead Man Switch is as follows:
2T MODE
1. Press the trigger on the electrode holder.
2. The Power Source will now output the VRD volts and the VRD ON led will be lit.
3. Touch the Stick Electrode to the work and commence welding as usual.