Simple Check On Inverter Circuit Components; Troubleshooting Problems With Igbt Module - Mitsubishi Electric PUHY-P250YNW-A Service Handbook

[8-9 Troubleshooting Inverter Problems ]
8-9-14

Simple Check on Inverter Circuit Components

Turn off the power to the unit, and leave it turned 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 Refer to the following page(s). [8-9-15 Troubleshooting Problems with IGBT Module]
Rush current pro- Measure the resistance between terminals R1 and R5: 22 Ω±10%
tection resistor
R1, R5
Electromagnetic
relay
72C
DC reactor Measure the resistance between terminals: 1Ω or lower (almost 0 Ω)
DCL Measure the resistance between terminals and the chassis: ∞
Current sensor Disconnect the wiring connector from CNCT2, and measure the inter-teminal resistance: 280Ω±30Ω
ACCT Between pins 1 and 2 (U-phase), pins 3 and 4 (W-phase)
8-9-15

Troubleshooting Problems with 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 (∞ Ω) or not shorted (to 0 Ω).
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.
BS_08_C
This electromagnetic relay is rated at DC12V and is driven by a coil.
Check the resistance between terminals
4
1
ACCT-U
*Check ACCT wiring for correct phase and direction.
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
U W ACCT-W
Checking criteria
160Ω ± 10%
INV board CNRY
Open: ∞
INV board CNRY
At a voltage input of 12 VDC: 0Ω
chapter 8 -
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