Mitsubishi Electric CAHV-R450YA-HPB Service Manual page 163

[ X Troubleshooting ]
(5) Simple checking procedure for individual components of main inverter circuit
Turn off the power to the unit, and leave it turned off for at least 10 minutes. Check that the voltage across CN-P(+) and
CN-N(-) on the INV board is 20 VDC or less before removing components from the control box.
Part name
IGBT module See "Troubleshooting for IGBT Module" (X [3] -5- (6)) (page 154)
Rush current pro- Measure the resistance between terminals R1 and R5: 22 ohm ±10%
tection resistor
R1, R2
Electromagnetic
relay
72C
DC reactor Measure the resistance between terminals: 1 ohm or lower (almost 0 ohm)
DCL Measure the resistance between terminals and the chassis: ∞
Current sensor Disconnect the wiring connector from CNCT2, and measure the inter-terminal resistance: 280 ohm ±30
ACCT ohm
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.
HWE22020
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
X101, X102, X103
Coil
Across pins 1-2
2
INV board
FT100 and FT101
Contact
*Faston terminal removed
INV board
SC-U SC-V SC-W
U W
ACCT-U
- 154 -
Checking criteria
160 ohm ± 10%
INV board CNRY
INV board CNRY
At a voltage input of 12 VDC: 0 ohm
ACCT-W
GB