Diode Stack; Troubleshooting For Igbt Module - Mitsubishi Electric PURY-P72 Service Handbook

[ IX Troubleshooting ]
[TJMU-A]
(6) Diode stack (P96, P120, P144 models)
Measure resistances between each pair of terminals on the diode stack with a tester, and use the results for troubleshoot-
ing.Refer to (5) " Intelligent power module (IPM) " for notes on measurement and tester selection.
Judgment value (reference)
+ (P)
- (N)
to (L1)
Red (-)
to (L2)
to (L3)

(7) Troubleshooting for IGBT Module

Measure the resistances between each pair of terminals on the IGBT with a tester, and use the results for troubleshooting.
The terminals on the inverter board are used for the measurement.
1) Notes on measurement
ŒCheck the polarity before measuring. (On the tester, black normally indicates plus.)
ŒCheck that the resistance is not open (
ŒThe values are for reference, and the margin of errors is allowed.
ŒThe result that is more than double or half of the result that is measured at the same measurement point is not allowed.
ŒDisconnect all the wiring connected the INV board, and make the measurement.
2) Tester restriction
ŒUse the tester whose internal electrical power source is 1.5V or greater
ŒUse the dry-battery-powered tester.
(The accurate diode-specific resistance cannot be measured with the button-battery-powered card tester, as the applied volt-
age is low.)
ŒUse a low-range tester if possible. A more accurate resistance can be measured.
HWE09130
Black ( + )
+ (P) - (N) to (L1)
- - 5 - 200 5 - 200
ohm ohm
- -
5 - 200 -
ohm
5 - 200 -
ohm
5 - 200 -
ohm
ohm) or not shorted (to 0 ohm).
- 318 -
External view
to (L2) to (L3)
5 - 200
ohm
- -
Internal circuit diagram
- -
- -
L1 L2 L3
+
L1
L2
L3
-
GB