Hitachi RAS-50WX8 Service Manual page 80

Fig. 3-1 shows the power module and its peripheral circuit.
The three transistors on the positive + side are called the upper arm, and the three transistors on the negative - side, the lower arm.
Coil
FUSE (25A)
L
N
Noise filter
Terminal
coil
board
0.35mH
Power relay
R007
R008 Inrush current
protection
relay
Fig. 3-1 Power module circuit (U + is ON, V - is ON)
System Power module2
V +
U+
+ + +
- - -
U - V -
R24
B
DC
compressor
motor
U coil
A
W +
U
V
W
V coil
W coil
W -