Maintenance; Safety Precautions; Routine And Periodic Maintenance; Overload Protection - Lincoln Electric PRECISION TIG 375 ROHS Operator's Manual

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SAFETY PRECAUTIONS

WARNING
ELECTRIC SHOCK can kill.
• Only qualified personnel should
perform this maintenance.
• Turn the input power OFF at the
disconnect switch or fuse box
before working on this
equipment.
• Do not touch electrically hot
parts.
WARNING
To avoid receiving a high frequency shock, keep
the TIG torch and cables in good condition.

ROUTINE AND PERIODIC MAINTENANCE

Very little routine maintenance is necessary to keep
your Precision TIG ® 375 running in top condition. No
specific schedule can be set for performing the follow-
ing items; factors such as hours of usage and machine
environment should be considered when establishing
a maintenance schedule.
• Periodically blow out dust and dirt which may accu-
mulate within the welder using an air stream.
• Inspect welder output and control cables for fraying,
cuts, and bare spots.
• Inspect the spark gap at regular intervals to maintain
the recommended spacing. See the Service
Procedures (See Service Procedures in this
Section) for complete information on spark gap set-
tings.
• The fan motor has sealed ball bearings which
require no maintenance.

MAINTENANCE

OVERLOAD PROTECTION

FAN-AS-NEEDED (F.A.N.)
The Precision TIG
which means the cooling fan will operate only while
welding; then for about 8 minutes after welding has
stopped to assure proper machine cooling. This helps
reduce the amount of dust and dirt drawn into the
machine with the cooling air. The cooling fan will oper-
ate briefly when the machine power is initially turned
on, and continuously while the yellow Thermal
Shutdown Light is lit (see Thermostatic Protection).
THERMOSTATIC PROTECTION
This welder has thermostatic protection from excessive
duty cycles, overloads, loss of cooling, and excessive
ambient temperatures. When the welder is subjected
to an overload, or inadequate cooling, the primary coil
thermostat and/or secondary coil thermostat will open.
This condition will be indicated by the illumination of
the yellow Thermal Shutdown Light on the front panel
(see Item 10 in Section B). The fan will continue to run
to cool the power source. Postflow occurs when TIG
welding is shut down, but no welding is possible until
the machine is allowed to cool and the yellow Thermal
Shutdown Light goes out.
NO ARC PROTECTION
The machine outputs (Background / OCV, gas and HF)
will be shutdown, if the trigger is closed without weld-
ing for 15 seconds to protect the Background resistor
from overheating with F.A.N. cooling off, as well as to
conserve on gas waste.
AUXILIARY POWER CIRCUIT BREAKER
This machine includes a 5 amp circuit breaker, located
on the opposite side of the upper case back, for pro-
tection of the 220vac Schuko type cooler receptacle.
PRECISION TIG ® 375
® 375 has the F.A.N. circuit feature,
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