Thermal Arc 181i FABRICATOR Service Manual page 24

FABRICATOR 181i
2. Digital Amps Meter
The digital amperage meter is used to display both the pre-set current (Stick and TIG modes only) and
actual output current (all modes) of the power source.
At times of non-welding, the amperage meter will display a pre-set (preview) value in both MMA (Stick) and
GTAW (TIG) modes. This value can be adjusted by varying the amperage potentiometer (item 4). Note that
in GMAW/FCAW (MIG) mode, the amperage meter will not preview welding current and will display zero.
When welding, the amperage meter will display actual welding current in all modes.
At the completion of welding, the amperage meter will hold the last recorded amperage value for a period
of approximately 10 seconds in all modes. The amperage meter will hold the value until; (1) any of the front
panel controls are adjusted in which case the unit 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 unit will return to preview mode.
3. Amperage Control (Wirespeed)
The amperage control knob adjusts the amount of welding current delivered by the power source. In MMA
(stick) and GTAW (TIG) modes, the amperage control knob directly adjusts the power inverter to deliver
the desired level of output current. In GMAW/FCAW modes (MIG), the amperage knob adjusts the speed of
the wire feed motor (which in turn adjusts the output current by varying the amount of MIG wire delivered
to the welding arc). The optimum wire speed required will dependent on the type of welding application.
The setup chart on the inside of the wire feed compartment door provides a brief summary of the required
output settings for a basic range of MIG welding applications.
4. MIG Torch Adaptor (Euro Style)
The MIG torch adaptor is the connection point for the MIG welding torch. Connect the torch by pushing
the torch connector into the brass torch adaptor firmly and screwing the plastic torch nut clockwise to
secure in position. To remove the MIG Torch simply reverse these directions.
5. Positive Welding Output Terminal
The positive welding terminal is used to connect the welding output of the power source to the appropriate
welding accessory such as the MIG torch (via the MIG torch polarity lead), electrode holder lead or work
lead. Positive welding current flows from the power source via this heavy duty bayonet type terminal.
It is essential, however, that the male plug is inserted and turned securely to achieve a sound electrical
connection.
Loose welding terminal connections can cause overheating and result in the male plug being fused
in the bayonet terminal.
6. MIG Torch Polarity Lead
The polarity lead is used to connect the MIG torch to the appropriate positive or negative output terminal
(allowing polarity reversal for different welding applications). In general, the polarity lead should be
connected in to the positive welding terminal (+) when using steel, stainless steel or aluminium electrode
wire. When using gasless wire, the polarity lead is generally connected to the negative welding terminal (-).
If in doubt, consult the manufacturer of the electrode wire for the correct polarity. It is essential, however,
that the male plug is inserted and turned securely to achieve a sound electrical connection.
Loose welding terminal connections can cause overheating and result in the male plug being fused
in the bayonet terminal.
Operation
CAUTION
CAUTION
4-2
OPERATION
Manual 0-5152