Image Industries QuikLinx SW750, Operation Manual

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Section 3
Normal Operation
20
AUTOMATIC SAFETY SHUTDOWN
This welder includes an Automatic Safety Shutdown. There are two ways the safety shutdown can be activated:
Thermal Protection
There are 2 levels of thermal protection. When the power source detects that it is getting warm, the unit will activate
the cooling fan. The fan will operate until the temperature of the power source has dropped below the cooling threshold.
The second stage of thermal protection will prevent the unit from welding in the event that the fan can not cool the power
supply adequately. The unit will not weld until it has returned to a safe operating temperature. The unit can go into thermal
overload for several reasons. The first reason would be a malfunction in the unit itself. The second reason would be that the
duty cycle has been exceeded. Other reasons include: inadequate cooling, restricted air flow, feet taken off, etc. The thermal
LED will be lit at this point.
When the unit cools down the thermal overload protection will automatically reset. After the thermal overload has reset
the unit will function normally and the thermal LED will turn off.
NOTE: if the unit is in thermal overload, do not turn off the unit. The fans need to run to cool down the unit.
Shorted Weld SCR
If the microprocessor detects voltage at the output terminals when the unit is not welding it will shut the unit off. This
means that one of the six main switching devices has malfunctioned. If this condition occurs, the unit could potentially weld
without triggering a weld tool. This is a potentially dangerous condition. The microprocessor detects this condition and
shuts the welder down. The unit can be restarted, but will shut down almost immediately once this condition is detected.
The unit must be repaired.