18Ap1:3 Temperature Monitoring; 18Ap1:4 Arc Voltage Monitoring - ESAB Caddy Tig 2200i AC/DC Service Manual

18AP1:3 Temperature monitoring
Principle diagram of the temperature monitoring circuits
The temperature monitoring circuit senses the temperature of the IGBT
modules, IC1 and IC2, that are fitted to circuit board 18AP2. Two NTC
resistors, NTC_IC1 and NTC_IC2, are used as sensors.
The output of the monitoring circuit is sensed by the processor, which in turn
stops the machine if overtemperature occurs.
If the temperature exceeds 110 _C the power source is stopped. It cannot be
restarted until the temperature is below 55 _C.
If overtemperature is sensed by NTC_IC1, fault code 7 is displayed and if
overtemperature is sensed by NTC_IC2, fault code 6 is displayed.
To check the NTC resistors: see page 50.
18AP1:4 Arc voltage monitoring
The arc voltage monitoring circuits measures the output voltage from the
power source. The voltage is displayed by the control panel.
The welding process control and no--load voltage reduction are maintained by
circuit board 20AP1, see 20AP1:7 Arc voltage feedback on page 32.
ct33_18
- - 22 - -
S0740 800 179/E071123/P64