Kemppi MinarcTig Evo 200 - Overheat Protection

Service manual MinarcTig Evo 200
Version 1.1.5.
29.9.2015
20
Kemppi Oy
4.2.1.5. Overheat protection
Main transformer PTC is soldered to the Z001 main circuit card:
 Measure the resistance: It should be less than 100Ω
 In over temperature situation PTC goes to high-resistance mode (>10kΩ)
 Machine gives temperature alarm at 1,5kΩ
 A broken PTC has usually hundreds of kilo ohms resistance or no value at all.
Note that the PTC signal is only delivered onto the Z001, the control logic is on the A001 control card.
Primary GND,
TP5
+390VDC,
DC-link,
TP4
Measuring points for PTC (160
o
C)
is X15 and X16.
Value in 22
o
C is 75 ohms.