Hitachi RAS-E08H2A - Page 60

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6-7. Outdoor DC
F
an Motor con
t
ro
l circui
t
This model uses DC Fan Motor which has a controller circuit built in the Motor
.
This DC Fan Motor will rotate b
y
control voltage apply to
V
sp input
.
(V
(Voltage range: 1.7 to 7V DC
)
Motor will output FG pulse b
y
f
ollowing this motor r
e
v
olution
.
indoor microcompute
r
.
This PWM control signal will convert to Vsp voltage by smoothing circuit. (R242 & C209)
r
otation speed
.
D
C Fan Motor circuit has to match the Fan Motor revolution with instructed revolution. Such as...
F
G feedback: Faste
r
I
nstruction: Slower ... Decrease pulse width
F
G
fe
edback
:
Slo
w
e
r
I
nst
r
uction: Fas
t
er ..
.
Increase pulse width
F
G pulse is also used
f
or Fan Motor
f
ailure detection
.
Microcompute
r
w
ill monito
r
F
G pulse
30
s
econds a
f
te
r
st
a
r
t
the
f
an mo
to
r
.
If
there is no
s
ignal detected
,
it
will
conside
r
that the
F
an Moto
r
w
a
s
mal
f
unction and
st
op the operation
.
I
n this cas
e
,
L
D
302
on main
R
107 and IC4 are used
f
or Fan Moto
r
over curren
t.
V
sp high
:
F
aster ;
V
sp low
:
s
lower ;
V
sp lower than 1.7V
V
:
st
o
p
P
.W.B. will blink
12
times.
(
Fan Motor lock detected
)
F
G pulse will feed back to Outdoor microcomputer
53
.
Outdoor microcomputer will output PWM control signal from
24
by
f
ollowing the instruction
f
rom
F
an motor will start to rotate when Vsp was proceeding over than 1.7V, and generate FG pulse b
y
1
24
53
46
45
44
HIC