Lincoln Electric SQUARE WAVE TIG 355 Service Manual page 28

B-12
1. POWER ON/OFF — A momentary start/stop push-
button, which controls the input contactor. If the
input power supply goes off or if the thermostat in
the welder trips, the start pushbutton must be
pressed to restart the welder.
2. PILOT LIGHT — Indicates when the input contac-
tor is energized (power is on).
CAUTION
Do not switch polarity under load.
3. POLARITY SWITCH — Selects DC-/AC/DC+
4. FUSE F1 — 0.5 amp control circuit fuse protects
the control transformer from overloads. Input over-
voltage protection circuitry will blow this fuse to
protect electronic components if the input voltage
to the welder is too high (more than 40% over rated
voltage). If this fuse blows, the digital meters will
not light and the input contactor will not latch when
the Power On/Off Start pushbutton is pressed and
released.
5. FUSE F2 — 1.5 amp gas, water, and high fre-
quency fuse protects the circuitry that drives the
gas and water valves and the high frequency sup-
ply transformer. If this fuse blows, the valves and
high frequency will not work. However, the LEDs
for Gas and Water and High Frequency will still
light.
OPERATION
6. REMOTE RECEPTACLE — A six-pin circular con-
nector for an Arc Start switch or an Amptrol remote
current control.
7. 115 VOLT RECEPTACLE AND CIRCUIT BREAK-
ER — A duplex 15 amp grounded NEMA 5-15R
receptacle and 15 amp circuit breaker.
amps of 115 volt AC power is available continu-
ously whenever the power is on. The circuit break-
er button will pop out if it trips. Reset by pushing it
in after the circuit breaker cools and the overload
has been removed.
8. HIGH FREQUENCY INTENSITY CONTROL AND
SPARK GAP — This control changes the high fre-
quency intensity. Use the lowest intensity which
still gives good arc starting to minimize Radio
Frequency Interference (RFI). The spark gap is set
at the factory to the normal setting marked on the
cover plate. Instructions for larger or smaller gap
settings are also on the cover plate.
9. GAS AND OPTIONAL WATER VALVES —
Solenoid valves that open at the beginning of the
Preflow time and close at the end of the Afterflow
time.
The gas valve inlet and outlet are standard 5/18-18
right-hand female fittings. The water valve inlet
and outlet are standard 5/8-18 left-hand female fit-
tings. The fittings conform to CGA (Compressed
Gas Association) standards.
strainer to prevent particles from jamming the
water valve.
SQUARE WAVE TIG 355
B-12
Fifteen
Use a water line