Mitsubishi Electric e Series Service Handbook page 139

[ IX Troubleshooting ]
(5) Simple checking procedure for individual components of main inverter circuit
Turn off the power supplied to the unit, and leave it off for at least 10 minutes. Check that the voltage across pins 1 (+) and
5 (-) of the connector RYPN1 is 20 VDC or less before removing components from the control box.
Part name
IGBT module See "Troubleshooting for IGBT module".( IX [4] -5- (6)) (page 130)
Rush current pro- Measure the resistance between terminals R1 and R5: 22 ohm
tection resistor
R1, R5
Electromagnetic
relay
72C
DC reactor DCL Measure the resistance between terminals: 1ohm or lower (almost 0 ohm)
Measure the resistance between terminals and the chassis:
Current sensor Disconnect the wiring connector from CNCT2, and measure the inter-terminal resistance: 280Ω±30Ω
ACCT Between pins 1 and 2 (U-phase), pins 3 and 4 (W-phase)
(6) 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 INV board are used for the measurement.
1) Notes on measurement
Check the polarity before measuring. (On the tester, black normally indicates plus.)
Check that the resistance is not open (
The values are for reference, and the margin of errors is allowed.
The result that is more than double or half of the result that is measured at the same measurement point is not allowed.
Disconnect all the wiring connected the INV board, and make the measurement.
2) Tester restriction
Use the tester whose internal electrical power source is 1.5V or greater
Use 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.)
Use a low-range tester if possible. A more accurate resistance can be measured.
HWE20010
This electromagnetic relay is rated at DC12V and is driven by a coil.
Check the resistance between terminals
4
1
*Check ACCT wiring for correct phase and direction.
ohm) or not shorted (to 0 ohm).
Judgment method
Check point
3
INV board
X901, X902
Coil
Across pins 1-2
2
INV board
FT-P1 and FT-P2
Contact
*Faston terminal removed
INV board
SC-U SC-V SC-W
ACCT-U U W
- 130 -
10%
Checking criteria
160Ω ± 10%
INV board CNRY
Open: ∞
INV board CNRY
At a voltage input of 12 VDC: 0Ω
ACCT-W
GB