Measurement & Replacement Of Subassemblies; Insulation Measurement; Power Components Measurements - Hitachi L100 SERIES Service Manual

6. Measurement & Replacement of Subassemblies

6-1. Insulation Measurement

For L100 inverter, do not perform insulation measurements , otherwise MOV will be damaged.
(MOV; between R(L1)-G, S(L2)-G, T(L3)-G)

6.2. Power Components Measurements.

When checking the power components, the following procedure is recommended:
Clear voltage
Wait for capacitors discharge
Check capacitors for neutrality
Disconnect mains and motor wires
Test the diodes and IGBTs using a universal tester with a diode function.
Visual check is important for the ISPM, check the outlooking such as smoke trace.
Note: In this test, the absolute values are not so important, since they depend strongly on the test
device used. The uniformity of the measured value is more important.
[1] DC BUS Measurement
Check "+" <- " - " voltage Zero.
Resistance Measurement
From
+
P1, PD are located on the CB board / snubber board.
Check "+1" and "+" terminal are shorten by (copper) bar.
[2] Softcharge Resistor (RS) , Thyristor (THY) Measurement
Resistance Measurement
From
P1
PD
(From P1 To PD
To
-
To
PD
P1
From PD To P1 ;if RS was opened)
Allowable Value
50kohm or more
Allowable Value
15 to 25 ohm
6-1