20Ap1:1 Power Supply; 20Ap1:2 Fan Control - ESAB Aristo Mig 3001i Service Manual

20AP1:1 Power supply
+24 V Internal and external power supply.
+15 V Internal power supply on 20AP1.
-15 V Internal power supply on 20AP1.
+5 V Internal power supply on 20AP1.
+2.5 V Internal power supply on 20AP1.
Uan 5 V internal reference voltage on 20AP1.
Uref 2.5 V internal reference voltage on 20AP1.
20AP1:2 Fan control
When the mains power supply is turned on, the fans are off. After about 4
seconds they start and run at full speed, for a short moment, before shutting
down until welding starts.
The fan speed depends on the welding current. For loads up to 110 A, the fans
run at low speed, supplied at about 18 V. At load currents above 110 A, the
fans are supplied at 24 V and run at full speed. On conclusion of welding, the
fans continue to run for 6.5 minutes.
If the welding current is above 110 A and then is reduced to a lower value, the
fans continue to run at full speed for 6.5 minutes, before dropping to the lower
speed.
If overtemperature is detected, the fans run at high speed until the power
source has cooled down to normal temperature.
ca41_20_1 - 27 -
S0740 800 196/E101019/P76