Hitachi RAC-50YH4, Service Manual

Page: 71 / 112

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7. Drive Circuit
Fig. 7-1 shows the drive circuit.
The circuits for U phase, V phase and W
phase have the same Configuration.
●
In low speed rotation mode (PWM range), as shown in Fig. 7-2, 0-5V chopper signal is ouput from microcomputer for each phase. S
ignal
output from microcomputer is ouput to IC1 and is inverted by active Lo to become 0-15V chopper signal; it is then drive the tra
nsistor
of each phase.
●
In high speed rotation mode (PWM range), as shown in Fig. 7-3, 0-5V drive signal is ouput from microcomputer for each phase (wi
th
no chopper because of full duty). Signal output from microcomputer is input to IC1 and is inverted by active Lo to become 0-15V
drive
signal; it is then drive the transistor of each phase.
Fig.. 7-1
6
5
4
3
2
1
MICR
OCOMPUTER
A
R512
R521
R511
R510
R509
R508
R507
10
9 4 3 2 1 8 7 6 5
1
13 14 15 16 17 18
1
23 11
8 7 5 4
10
6 3 9
2 3 4 5 6 7 8 9
10 11 12 13 14
15 16 17 18 19 20 21 22 23 24 25 26 27 28
19 20 21
2 3 4 5 6 7 8 9
10
12 22
B
B
B
45 44 43 42 41 38 39 40
46
IP CUTTER
Id CONTR
O
L CIRCUIT
0V
17V
R501
C404
CN14
17V
0V
PWB (MAIN)
SPM2
0V 17V U
+
V
+
W
+
U
–
V
–
W
–
IP Id
IC1
VCC
VCU
PGU
U
VCV PGV
V
VCW PGW
W
NGU
NGV
NGW
SVT SWT SUB SVB SWB F OC CB A
0
A– GL1 GL2 SUT
R502 R503 R504 R505 R506
Q506
R536
R535
R525
Q504
R534
Q503
R524
R533
Q502
Q501
R522
R532
R531
R526 Q505
R523
HIC
P2 N1
HIC
– +
GR
Y
R24
U
COMPRESSOR MO
TO
R
V
W