Tweco 281 Thermal Arc Fabricator - Manual (Page 42)

FABRICATOR 281
4-4 April 10, 2006
0
100
200
300
400
500
600
700
800
900
25 50 75 100 125 150 175 200 225 250 275 300 325
Current (Amps)
Wi
re Speed (IPM)
(.030 - AL)(.035 - AL)
(.047 - AL)
Art # A-07453
ALUMINUM
Figure 4-5: Aluminum - AMP to IPM Conversion
Thermal Overload
The critical component for thermal protection are the rectifier stack and the transformer, which are fitted with
thermal overload cut out devices. If the overload is activated then the machine should be left to cool for approximately
15 minutes before resuming welding. If the Power Source is operated within its duty cycle, the thermal overload
will not activate. Refer to section 2.09 for an explanation of duty cycle and section 2.10 for the power supply
specifications.
Wirespeed Control
The Wirespeed Control knob controls the welding current via the electrode wire feed rate, i.e. the speed of the wire
feed motor.
Coarse Voltage Control Switch
The Coarse Voltage Control sets the voltage level to the welding terminals as it is rotated in the clockwise direction.
Fine Voltage Control Switch
The Fine Voltage Control switch increases the voltage (in smaller increments than the Coarse switch) as it is
rotated in either direction.
CAUTION
The Coarse & Fine Voltage Control switches MUST NOT BE SWITCHED during the welding process.
Positive and Negative Welding Current Terminals
Refer back to Figure 4-1. Both terminals located at the bottom of the unit are shown without the terminal knob.
Both knobs must be firmly secured before attempting to weld.