TM 5-3431-207-15
(2) Start the motor-generator in accordance
welding operation. the job selector should
with paragraph 21.
be set in the yellow section for a high
open-circuit voltage (large electrode
(3) Place the polarity switch in the up or down
range).
position as required.
(4) For special jobs requiring the smallest
(4) Set the job selector (fig. 3) to the desired
size of electrodes and very low current
voltage.
values, the job selector should be set in
the special applications section for a low
(5) Set the current control (fig. 3) to the
open-circuit voltage.
desired amperage.
Warning:
Do not perform any
(6) Strike an arc.
welding operation without a welders
helmet. The flash of the welding arc
(7) If the arc is weak, turn the job selector up.
can cause injury to the eyes.
If the arc is too cold, turn the current
control up 10 to 20 amperes and turn the
(5) The approximate current range for bare
job selector down.
and lightly coated electrodes is shown in
Warning:
Do not adjust welding
for gaseous and slag types of electrodes.
controls while maintaining arc.
Table I. Current Setting Range for Bare or
(8) If, when the correct current is obtained,
Lightly Coated Electrodes
the job selector is positioned beyond the
desired setting, adjust the current control
Electrode
Current
Electrode
Lengths
up and return the job selector to the
diameter
minimum
maximum
(in.)
desired setting, so that the necessary arc
(in.)
(amps)
(amps)
can be produced.
3/32
70
90
11 1/2
24. Operation Under Unusual Conditions
1/8
110
135
14 or 18
5/32
150
180
14 or 18
a. Operation in Extreme Cold (Below 0 F.)
3/16
180
220
14 or 18
1/4
250
300
14 or 18
5/16
300
14 or 18
(1) Before starting the machine, disconnect
its source of electrical power and wipe the
Table II. Comparison of Current Used with Gaseous
electrical components free of ice and
and Slag Types of Electrodes
moisture. Do not disturb the wiring as it
becomes brittle with extreme cold.
Electrode
Gaseous types
Slag type
(2) Connect the welding machines source of
diameter
Flat position Vertical and
fiat
the electrical supply.
(in.)
(amps )
Overhead
position
(3) Start motor-generator in accordance with
position
(amps)
(amps)
(4) Begin usual welding operations.
3/32
60
60
b. Operation in Dusty or Sandy Areas.
1/8
120
110
130
5/32
150
140
160
(1) When the installation is permanent, erect
3/16
175
160
200
a protective cover for it. When
a
1/4
200
300
temporary installation is made, take
5/16
325
400
advantage of natural barriers as much as
possible. Keep the unit as clean as
c. Dual Control. Dual control of amperage and
possible, paying special attention to the
voltage can be accomplished by the use of the job
control panel.
selector and the continuous current control. The dual
control is utilized by the following steps:
(2) Connect the welding machines source of
electrical supply.
(1) Place the polarity switch (fig. 3) in the
OFF position.
12
