20Ap1:4 Temperature Monitoring; 20Ap1:5 Overvoltage And Undervoltage Protection - ESAB Arc 4000i Service Manual

One end of the CAN bus is in the power source and it must be fitted with a
terminating resistor, R28 in the circuit diagram on page 34. If a CAN remote
control with terminating resistor, or an external terminating resistor, is
connected to the power source, the internal terminating resistor must be
disconnected from the power source.
To disconnect the terminating resistor: remove the jumper from terminal D.
Circuit board 20AP1, terminal D
The CAN remote controls and CAN adapters have a built--in terminating
resistor. This resistor can be disconnected or connected by moving a jumper:
See the service manual for the CAN based remote controls (filename 0740 800
170).
20AP1:4 Temperature monitoring
Principal diagram of the temperature monitoring circuits
Thermal cutout switch 15ST1 is fitted under the winding of main transformer
15TM1, and opens at a temperature of 130°C.
Thermal cutout switch 15ST2 is mounted on the heat sink, beside the IGBT
transistors, and opens at a temperature of 80°C. See page 59 for fitting
instructions.
If either of the switches operates, the power source is stopped and LED D1 on
the front panel lights. The power source cannot be restarted until it has cooled
sufficiently for the switch(es) to reclose.
20AP1:5 Overvoltage and undervoltage protection
See 15AP2:2 on page 30.
cu19_20_1
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S0740 800 191/E080229/P78