Tweco 251 Thermal Arc Fabricator - Manual (Page 37)

FABRICATOR 251
Manual No. 0-4847 3-15 INSTALLATION
Connected for D.C.
Electrode Negative
(DCEN) Welding
Work Lead
Art # A-07164
Figure 3-15: Polarity Connections for DCEN
Changing polarity process.
a. Locate the two terminal knobs at the front of the machine. Refer to Figures 3-14 and 3-15.
b. Remove both terminal knobs by rotating counterclockwise.
c. Set up the desired lead polarity as per Table 3-3 and as shown in Figures 3-14 or 3-15.
d. Place the Work Lead cable on the opposite terminal.
e. Replace both terminal knobs and tightly secure them to ensure good electrical connections.
CAUTION
Ensure terminal knobs are tightly secured and that there is no connection between positive and negative
terminals.
f. Reconnect the input power to the power supply.