with a disconnect switch.
long or shorter. Provide a 150 ampere fuse for 230-
(1) Check voltage source. Remove the two screws
volt input and an 80 ampere fuse for 460-volt input.
at the bottom of the contactor access panel on the
Note. The machine will operate from a single phase power
rear of the machine. Open the hinged panel.
line or from any one phase of a three-phase power line. For use on
(2) Check that the jumpers (voltage-change bus
three-phase power lines, choose any two of the three hot wires
bars) are located properly for the available voltage.
plus a grounding wire for correction to the welding machine.
Using conduit, bring the two primary power leads and the ground
wire through the cable entrance hole directly below the primary
access panel door).
panel of the welding machine. Connect the two primary power
(3) Connect the welding machine to ac power.
leads to the line terminals on contactor and primary panel. Attach
Use no. 3 AWG wire for 230-volt input and no. 6
the grounding wire to the grounding screw located below the con-
AWG wire for 460-volt input when wires are 25 feet
tactor inside the rear door.
Section II. MOVEMENT TO A NEW WORKSITE
2-5. Dismantling for Movement
a suitable lifting device, If the machine is to be
a. Reverse the sequence of the steps taken in para-
moved within a building, it can be moved with a fork-
graph 2-4, disconnecting cables, ground connections,
lift, or on its skids.
and hoses and/or piping from gas and water con-
2-6. Reinstallation after Movement
Proceed in accordance with the instructions given in
b. Cover the water and gas connection fittings if
the welding machine is to be moved other than a
short distance. Load the machine on the carrier using
Section III. CONTROLS AND INSTRUMENTS
(3) GAS- WATER switch. This two-position
switch turns the gas and water ON or OFF. It is
This section describes the various controls and in-
used in the ON position during TIG welding, and
struments and provides the operator sufficient in-
must be OFF for metallic arc welding.
formation to insure proper operation of Model
(4) GAS- WATER indicator light. This light
MD301 FED Inert Gas Shielded Arc Welding Ma-
glows red when the GAS-WATER switch is in the ON
position and goes out when timer Ml times out.
2-8. Controls and Instruments
a. Figure 2-4 illustrates the front panel of the ma-
tion switch applies power to a high-frequency `trans-
former when in the ON position, for use in high fre-
chine, which contains all operator's controls and in-
struments. Figure 2-5 illustrates the controls in the
light glows red when the HIGH FREQUENCY
b. The purpose of the controls and instruments are
switch is ON. The light is located beside the switch.
(1) POWER switch. Two-position momentary
It goes out after the arc is started if HIGH FRE-
QUENCY dropout switch is in START ONLY posi-
switch turns power ON or OFF.
(2) POWER indicator light. Located beside the
POWER switch, this light glows red when the POW-
(7) HIGH FREQUENCY START control. This
control is an intensity selector used to dampen the
ER switch is ON and power is connected.