Hitachi RAS-E10H2 - IPM Circuit Operation

Fig. 5-1
Microcomputer
External ROM
SCL
SDA
0V
0V
0V
5V
5V 5V
C401
IC401 or IC402 (E
2
PROM)
R404 R403
27
26
1
2
3
4
8
7
6
5
}
Voltage at point A
Waveform
T1 = Low speed
T2 = High speed
T2
T1
Voltage at point
B
Waveform
T1
Voltage at point
C
Waveform
Speed
(min
-1
)
T2
Voltage at point B (V
)
(1400)
7.
F
an Motor Drive Ci
rc
ui
t
• F
or
the
point
A
,
15.7
kHz
PWM
pulse
will
be
output
from
the
pin
24
on
the
micro
computer
as
sho
wn
in
Fig.
7
-2.
The
pulse
range
will
va
ry
w
ith
diff
erent
command
speed.
• T
he
pulse
is
con
ve
r
ted
into
the
analog
v
oltage
by
the
R751
and
C751
and
applied
to
the
f
an
motor
as
the
speed
command v
oltage
.
Fig.
7
-3
sho
ws
the
relation
betw
een
the
v
oltage
at
the
due
to the condition of the unit.)
• T
he
fa
n motor outputs the f
eedbac
n motor outputs the feedbacn motor outputs the f
k pulse of the speed,
which
is
input
into
the
pin
14
on
the
micro
compute
r.
This
pulse
is
equiv
alent
to
a
frequency
of
12/60
speed.
(Example: 1000 min
-
1
x 12/60 = 200 Hz
)
The
micro
computer
monitors
the
frequency
and
adjusts
command speed.
•
stopped temporarily as f
an loc
k error
.
After 10 seconds
, restar
t the output of the pulse
.
If
fa
n lo
ck
error
is
detected
twice
within
30
minute
s,
all
units
are
stopped
and
the
unit
will
come
in
the
f
ailure
mod
e.
(The timer lamp will b
link 10 times
.)
10 2 3 4 5
T1
T2
point B and the speed. (Some differences will occur
If the
fe
edback pulse is 100 min
-
1
or less due to a loc
ke
d fan motor or failure, the fan output will be
the output pulse range of the pin
24
so as to keep the
M
24
14
C751
0V
A
R751
C631
R631
0V
C
CN10
0V
5V
B
35V
Micro computer
Fan motor
Fig. 7-1
DC fan
motor output
DC fan motor
Speed
feedback
Fig. 7-2
Fig. 7-3
- 41
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