Protective Circuits; Thermal Protection; Overload Protection - Lincoln Electric PRECISION TIG 185 SVM169-A Service Manual

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PROTECTIVE CIRCUITS

Protective circuits are designed into the PRECISION
TIG 185 to sense trouble and shut down the machine
before the trouble damages the internal machine com-
ponents. Both thermal protection and current overload
are included. Fan as needed (F.A.N.) Fan runs for 5
seconds at power-up and stops at idle 8 minutes after
welding.

THERMAL PROTECTION

9. OVER TEMPERATURE LIGHT-
overheats due to blocked air flow, high ambient air
temperature, or exceeded duty cycle, an internal ther-
mostat will open disabling the welding output and this
yellow light will illuminate. The cooling fans will contin-
ue to run to cool the unit during this time. The light will
go out when the unit cools and the thermostat resets.
Once the light goes out, the machine will again
become available to weld.
Once the machine cools sufficiently the thermostats
are self-resetting. If the thermostat shutdown is caused
THEORY OF OPERATION
by excessive output or duty cycle and the fan is oper-
ating normally, the power may be left on, and the reset
should occur within a 15 minute period. If the fan is not
functioning properly or the air intake louvers are
obstructed, then the input power must be removed and
the fan problem or air obstruction corrected.

OVERLOAD PROTECTION

The machine is electronically protected from producing
excessively high output currents. The output is limited
to 200 amps.
If the welder
PRECISION TIG 185
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