Hitachi SJ100 Series, Service Manual

Page: 30 / 75

6. Measurement & Replacement of Subassemblies
6-1. Insulation Measurement
For SJ100 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 appearance 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 Allowable Value
From To
+ - 50kohm or more
P1, PD are located on the CB board / snubber board.
Check “+1” and “+” terminal are shorten by (copper) bar.
[2] Soft charge Resistor (RS) , Thyristor (THY) Measurement
Resistance Measurement Allowable Value
From To
P1 PD
PD P1
15 to 25 ohm
(From P1 To PD From PD To P1 ;if RS was opened)
6-1