Hitachi RAC-18SX8, Service Manual

Page: 143 / 254

11. Cleaner drive circuit
Fig. 11-1
0V
0V 0V 0V
5V
0V
0V
0V
5V
R711
2
CN10
1
ＰＡ−２Ｐ−（
vertical
）
Cleaning limit switch, right
(Lo, OFF; Hi, ON)
Cleaner position detection switch, right
19
6 1
13
7 11
12
2
4
9
15
17
14
8
10
20
5V
R912
R913
3
18
16 5
R911
Cleaning Id
IC911
M
Cleaning motor
Vref setting
Clock signal
Reset signal
STBY signal
Forward/reverse
signal
Excitation mode
setting
CN8
ＰＡ−４Ｐ−（ vertical ）
12V
R616
30
34
32
31
33
29
93
6
Microcomputer
IC601
62
Ventilator power
(Lo, OFF; Hi, ON)
4
1
2
3
5
6
7
+
-
IC931
(2/2)
C911
R915
R917
R916
D912
R918
C913
R914
C912
D911
C914
R919
C614
R713
R902
R903
Q902
C902
R906
6 11
IC682
Red
Black
・
The cleaning wiper scrapes out any dirt and dust from the filter mounted at the suction inlet up to the dust catcher, thereby
cleaning the filter.
・ The cleaner is activated only when being initialized at power-on and in either of the operation modes: "manual cleaning,"
"automatic cleaning," and "forcible cleaning."
In either of the above operation modes, control of the microcomputer (IC601) will turn on the Q902, with the 12 V component
passing the driver IC (IC911) and powering the cleaning drive motor.
・ The cleaning motor will, by using the driver IC (IC911), perform micro-step sine wave drive (excitation of W1-2). When moving
from the right to the left, the motor current will show a waveform as illustrated in the chart below.
The waveform may change slightly according to the rotation speed.
100
(%)
80
60
40
10 0 20 30 40 50 10 0 20 30 40 50
20
0
-20
-40
-60
-80
-100
Phase B
Phase A
・
The cleaning wiper moves rightward as the indoor unit is viewed from the front. Pressing the cleaning position detection
switch will return the product to its initial position. (If it is already in its initial position, it will remain there.)
The wiper will start at its initial position and move leftward. It passes by the dust catcher and, as it reaches the left end, the
cleaning drive motor will reverse and change its direction rightwards.
When the cleaning wiper presses the cleaner position detection switch mounted at the right end of the indoor unit, the
cleaning operation will be complete.
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