Hitachi RAS-70YH5 Service Manual page 95

HOW TO CHECK SYSTEM POWER MODULE
Checking system power module using tester
Set tester to resistance range (X 100)
If indicator does not swing in the following conductivity check, the system power module is normal.
(In case of digital tester, since built-in battery is set in reverse direction, + and – terminals are reversed.)
CAUTION
If inner circuit of system power module is disconnected (open), the indicator of tester will not swing and this may
assumed as normal. In this case, if indicator swings when + and – terminals are connected in reverse of diagram
below, it is normal. Furthermore, compare how indicator swings at U, V and W phases. If indicator swings the same way
at each point, it is normal.
– +
– +
– +
–
+
P1 N1 P2 U P1 N1 P2 U
+ – + –
L2 L1 L2 L1
+ + – –
W V W V
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