Mitsubishi Electric PQHY-P72ZLMU-A Service Handbook page 358

[ IX Troubleshooting ]
(5) Simple checking procedure for individual components of main inverter circuit
Before inspecting the inside of the control box, turn off the power, keep the unit off for at least 10 minutes, and confirm that
the voltage between FT-P and FT-N on INV Board has dropped to DC20V or less.
Part name
IGBT module See "Troubleshooting for IGBT Module ". (IX [4] - 6 - (6) )
Rush current pro- Measure the resistance between terminals R1 and R5: 22 ohm
tection resistor
R1, R5
Magnetic Contac-
tor
52C
DC reactor DCL Measure the resistance between terminals: 1ohm or lower (almost 0 ohm)
Measure the resistance between terminals and the chassis:
(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.
HWE15150
This electromagnetic relay is rated at 230 VAC and is driven by a coil.
Check the resistance between terminals
Upper
Installation
direction
ohm) or not shorted (to 0 ohm).
Judgment method
Coil Between Terminals A1 and A2
Between Terminals 1 and 2
Contact
Between Terminals 5 and 6
- 349 -
10%
Check point Checking criteria( )
W
Not to be short-circuited
GB