Hypertherm Powermax1250 Service Manual - Manual (Page 45)

MAINTENANCE
3-12 powermax1250 Service Manual
3
IGBT device test using a non-Hypertherm tester
The device tester shown in Schematic for building an IGBT tester has one LED and one pushbutton switch that are
used in combination to perform two tests.
Note: Before an IGBT can be tested, it must be electrically isolated from all circuits. If the IGBT is installed in
a power supply, remove the power board and any lead connections before testing.
1. Inspect the IGBT for cracks or black marks. If damaged, replace the IGBT.
2. Verify that the 9v battery reads greater than (>) 8.0v.
3. Connect the test leads as shown below.
4. With the test leads connected and without pressing the pushbutton switch, the LED should not illuminate. If the
LED is illuminated, then the IGBT is shorted. Replace the IGBT.
5. With the test leads connected, press the pushbutton switch. This time, the LED should illuminate. If the LED
does not illuminate, then the IGBT is open. Replace the IGBT.
Yellow lead
Gate 1 (G1)
Black lead
Emitter 1 (E1)
Red lead
Collector 1 (C1)
IGBT, Inverter
test 1
Yellow lead
Gate (G)
Black lead
Emitter (E)
Red lead
Collector (C)
IGBT, PFC
Yellow lead
Gate (G)
Red lead
Collector (C)
Black lead
Emitter (E)
IGBT, Pilot arc
IGBT, Inverter
test 2
Yellow lead
Gate 2 (G2)
Black lead
Emitter 2 (E2)
Red lead
Collector 2 (C2)