rotary ground may be used. This eliminates tangling of
the ground cable and assures good ground contact
throughout the welding operation. Various types of
grounds for stationary and rotary weldments are shown in
Figure 3-38.
REVIEW QUESTIONS
Write your answers on a separate sheet of paper. Do
not write in this book.
1. The power supply produces welding current at
_____ voltages.
2. Welding power supplies are made to operate on
_____ or _____ phase primary current.
3. All welding power supplies have a _____ output
current which is established by the design of the
machine to _____ specifications.
4. The time at rated load at which the machine will
operate without harm to the machine is called the
machine _____ _____.
5. This time period is based on a _____ -minute
period.
6. The letters OCV with regard to welding power
supplies define the _____ _____ _____ established
on the machine.
Chapter 3 Equipment Set-up and Control 39
Figure 3-35. Anti-spatter spray is used to prevent spatter
buildup on the end of the nozzle. This should be applied often
to the end of the nozzle and the contact tip. (G.S. Parsons Co.)
Figure 3-36. Special tools like this one are used to remove
spatter from the nozzle tip.
Welding Current (amps.) Cable Size (No.)
100
150
200
250-300
300-450
500
600
4
2
2
1/0
2/0
3/0
4/0
Recommended
Minimum
Cable Sizes
Figure 3-37. Cables should be inspected regularly for cuts or
for damage from excessive heating. Always replace with proper
size, as shown on this chart.
Figure 3-38. Many different types of ground clamps are
available for use with GMAW. They must work properly and
have clean points for contact with the part being welded.
A—Spring-type clamp. B—Screw-type clamp. C—Rotary ground.
(Tweco Products, Inc.)
A
B
C