Hitachi RAM-18QH5E, Service Manual

Page: 41 / 78

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3. System Power Module Circuit
●
Fig. 3-1 shows the system power module and its peripheral circuit. (Current ACT module and power module are combined into one u
nit.)
The three transistors on the positive
e
side are called the upper arm, and the three transistors on the negative
d
side, the lower arm.
Fig.
3-1 System po
w
er module circuit (U
+
is ON,
V
–
is ON)
+
W
U V W
W
—
+
V
V
—
+
U
U
—
A
+
—
DC Compressor motor
U coil
V coil
W coil
System Power module 2
+
—
+
—
+
—
R24
INVER
TER
0.35
m
H
Power relay
Coil
R003
R002
Inrush current protection relay
C006
R004
Noise filter coil
L N
T
erminal
board
FUSE (25A)
ACT
MODULE