Miller Electric KC237900 - Manual (Page 17)

OM-530 Page 13
4-2. POLARITY SWITCH (Figure 4-1)
+ ( )
ELECTRODE
POSTIVE
( )
LECTRODE
NEGATIVE
POLARITY SWITCH
DO NOT SWITCH
WHILE WELDING
CAUTION: ARCING can damage switch
contacts.
•
Do not change POLARITY SWITCH position
while welding or under load.
The POLARITY switch provides a means of selecting ei-
ther electrode negative or electrode positive weld output
polarity without having to change the output cable con-
nections.
Placing the POLARITY switch in the ELECTRODE
NEGATIVE position causes the ELECTRODE output
terminal to be negative and the WORK output terminal
to be positive. Conversely, if the POLARITY switch is
placed in the ELECTRODE POSITIVE position, the
ELECTRODE output terminal is positive and WORK
output terminal is negative.
4-3. GAS/COOLANT SWITCH (Figure 4-1)
ON
OFF
/
GAS/COOLANT
The function of the GAS/COOLANT switch is to govern
the operation of the gas and water solenoids and the
POSTFLOW timer. When this switch is in the OFF posi-
tion, the gas and coolant valves and POSTFLOW timer
are disabled (out of the circuit). When this switch is in the
ON position, the gas and coolant valves and POST-
FLOW timer are energized (in the circuit). The ON posi-
tion of this switch is normally used for Gas Tungsten Arc
Welding applications; the OFF position is used for
Shielded Metal Arc Welding applications.
4-4. GAS/COOLANT POSTFLOW CONTROL
(Figure 4-1)
t 2
POSTFLOW
IMPORTANT: The POSTFLOW timer is disabled
whenever the GAS/COOLANT switch is in the OFF po-
sition.
An adjustable 0 to 60 seconds gas-coolant POSTFLOW
time control is provided for controlling the period of time
shielding gas and coolant are allowed to flow after the
arc is extinguished. The POSTFLOW time control gov-
erns the operation of a postflow timer within the TIG-
Unit.
Rotating the control in a clockwise direction increases
the postflow time. The scale surrounding the POST-
FLOW time control is calibrated in seconds to aid in the
selection of a postflow time period suited to the individu-
al welding operation.
As soon as the contactor is deenergized, the postflow
timer begins to time out the selected period of postflow
time. Once the timer has timed out, the gas and coolant
valves close and thereby cut off shielding gas and cool-
ant flow. The timer automatically resets and is ready for
another weld cycle.
4-5. REMOTE HAND CONTROLS
WARNING: ELECTRIC SHOCK can kill; UN-
EXPECTED HIGH FREQUENCY DURING
PREFLOW can cause serious injury and
equipment damage.
•
Do not allow electroslope switch or other unit
control switch to be maintained closed during
preflow time.
•
Always close and immediately open control
switch to ensure that high frequency will not be
present during preflow.
If the unit is equipped with the optional electro-
slope and preflow timer, it is possible to have
high frequency present during preflow without
machine contactor energized.
A fingertip control (RCC-14) is supplied with every unit.
This control is a maintained-contact type switch used for
remote Amperage and Output (Contactor) control. The
fingertip control must be connected to the REMOTE 14
receptacle (see Figure 4-1 and Section 3-10) under the
front access door of the TIG-Unit to be functional. This
control is designed to be strapped to the torch handle for
convenient operation.
IMPORTANT: When employing the RCC-14 remote
control, the AMPERAGE switch on the TIG-Unit must
be in the REMOTE position for proper remote control
operation.
A momentary-contact type switch (RMLS-14) is addi-
tionally supplied with each unit equipped with an Elec-
troslope. This control must be connected to the RE-
MOTE 14 receptacle (see Figure 4-1 and Section 3-10)
under the front access door of the TIG-Unit to be func-
tional. It is necessary to press this switch each time a
new or different weld condition is desired. This switch al-
lows the operator to manually control the selection of the
welding conditions and duration of that condition. It fur-
ther gives the operator the capability of moving rapidly
from one condition to the next, if desired. It is necessary
to press this switch four times to advance the unit
through a complete weld cycle. Anytime that the arc is
broken (except during the initial condition), the Electro-
slope will automatically reset to Off. During the initial