Theory of operation, Thermal protection – Lincoln Electric SQUARE WAVE TIG 255 SVM100-A User Manual
Page 40
SQUARE WAVE TIG 255
E-7
THEORY OF OPERATION
A thermostat protects the machine from excessive
operating temperatures. Excessive operating temper-
atures may be caused by a lack of cooling air or oper-
ating the machine beyond the duty cycle and output
rating. If excessive operating temperature should
occur, the thermostat will prevent output voltage or
current and the yellow indicator light will glow.
Additionally, the display and keypad lights will turn off.
The fan will remain on during this period. The thermo-
stat is self-resetting once the machine cools sufficient-
ly. If the thermostat shutdown is caused by excessive
output or duty cycle and the fan is operating normally,
the power switch may be left on and the reset should
occur within a 15 minute period. If the fan is not turn-
ing or the air intake louvers are obstructed, then the
input power must be removed and the fan problem or
air obstruction be corrected.
THERMAL PROTECTION