20Ap1:5 Temperature Monitoring; 20Ap1:6 Shunt And Current Control Amplifier - ESAB Caddy Tig 2200i AC/DC Service Manual

20AP1:5 Temperature monitoring
The thermal overload switches, 15ST1 and 15ST2, are normally closed.
Terminal T2 of the circuit board is at 0 V.
15ST2, which is fitted on the heat sink, opens at 75 _C. 15ST1, which is fitted
in the winding of the main transformer, 15TM1, opens at 130 _C.
If either of the switches operates, the power source is stopped, fault code E06
is displayed.
The power source cannot be restarted until it has cooled sufficiently for the
switch(es) to reclose.
20AP1:6 Shunt and current control amplifier
The shunt produces 60 mV at a welding current of 100 A. The shunt response
is linear to the welding current.
If the shunt is not connected to the circuit board, resistor R2 supplies about
1.4 to 1.9 V to the shunt input. This blocks the current control amplifier, i.e. the
machine does not deliver any welding current.
ct33_20
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S0740 800 179/E071123/P64