Hitachi RAC-25WSE, Service Manual

Page: 77 / 142

1 . Cleaning unit drive circuit
Fig. 1 -1
9
9 9 9
9
9
9
5
&1 ˬ˝ˉˎˬˉ˄
vertical
˅
Cleaning limit switch, right
(Lo, OFF; Hi, ON)
Cleaning unit position detection switch, right
5
5
5
Cleaning Id
,&
7
M
Cleaning unit driving motor
Vref setting
Clock signal
STBY signal
Forward/reverse
signal
Excitation mode
setting
&1
ˬ˝ˉːˬˉ˄ vertical ˅
9
5
28
29
85
41
42
27
Microcomputer
IC601
Ventilator power
(Lo, OFF; Hi, ON)
,&
&
5
5
5
'
5
&
5
&
'
&
&
5
&
5
5
4
&
,&
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 cleaning unit 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 (
MICON
) will turn on the Q902, with the 12 V component
passing the driver IC (IC
7
11) and powering the cleaning unit driving motor.
·
The cleaning unit driving motor will, by using the driver IC (IC
7
11), 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.
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 unit driving motor will reverse and change its direction rightwards.
When the cleaning wiper presses the cleaning unit position detection switch mounted at the right end of the indoor unit, the
cleaning operation will be complete.
R942
R946
Vcc2(5V)
15 2
Vcc2(5V)
Vcc2(5V)
4
4
77