Hitachi RAS-E10H2 - Outdoor DC Fan Motor Control Circuit Details

Ope ra ti onmode
1→ 2→ 3→ 4→5→6→7→8 VALVE CLOSE
8→ 7→ 6→ 5→4→3→2→1 VALVE OPEN
ON
1
ON
2
OFF
3
OFF
4 5
OFF OFF
6
OFF
7
ON
OFF ON ON ON OFF OFF OFF OFF
OFF OFF OFF ON ON ON OFF OFF
OFF OFF OFF OFF OFF ON ON ON
8
④
③
②
①
④
③
②
①
Con ne ct or
Pin N o.
12V
0.9V
50ms. 75ms .
200ms.
6-6. Electric expansion valve control circuit
Fig. 6-14
Main P.W.B.
Electric
expansion
valve
Microcomputer
Valve4
Valve3
Valve2
Valve1
●
Electric expansion valve is driven by B-12V. Opening of the valve is controlled by feeding power to 1
or 2 phases of the 4-phase coil to switch the polarity of the coil.
●
The relation between the conducting phase switching direction and open/close direction is as shown
below. When the power is turned on, approx. 0.9 V is applied to CN15 pins 1 to 4 ; when no power
is supplied, approx. 12 V is applied. When the power is reset, expansion valve performs initial
operation for 5 to 10 seconds.During initial operation, measure pins 1 to 4 of CN15 using
multimeter: If no change is found around 0.9 V or 12V
, expansion valve or microcomputer is
defective.
●
Fig. 6-15 shows logic waveform during the operation of expansion valve.
Table 6-4
Fig. 6-15
CN 15
Pin No.
Lead
wire
Drive status
White
Yellow
Orange
Blue
6-7. Outdoor DC
Fa
n Motor cont
ro
l circuit
This model uses DC F
an Motor which has a controller circuit b
uilt in the Motor.
This DC F
an Motor will rotate
by
control v
oltage apply to
Vsp input.
(V
oltage range:
(Voltage range: (V
1.7 to 7V DC)
Motor will output FG pulse
by
f
ollowing this motor re
v
olution.
indoor microcomputer
.
This PWM control signal will convert to Vsp voltage by smoothing circuit (R242 & C209)
rotation speed.
DC Fan Motor circuit has to match the Fan Motor revolution with instructed revolution. Such as...
FG feedback: Faster
Instruction: Slower ... Decrease pulse width
FG
fe
edba
ck
:
Sl
ow
er
Instr
uction:
F
aster ...
Increase pulse width
FG pulse is also used f
or F
an Motor f
ailure detection.
Microcomputer
will
monitor
FG
pulse
30
seconds
after
star
t
the
fa
n
moto
r.
If
there
is
no
signal
detected,
it
will
consider
that
the
F
an
Motor
wa
s
malfunction
and
stop
the
operation.
In
this
case
,
LD302
on
main
R107 and IC4 are used f
or F
an Motor
ov
er current.
Vsp high
:
Faster ;
V
sp low
Vsp low V
:
slower ;
V
sp lower than 1.7V
Vsp lower than 1.7V V
:
stop
P.W.B. will blink 12 times
.
(Fan Motor lock detected)
FG pulse will feed back to Outdoor microcomputer
53
.
Outdoor microcomputer will output PWM control signal from
24
by following the instruction from
Fan motor will start to rotate when Vsp was proceeding over than 1.7V, and generate FG pulse by
1
24
53
46
45
44
HIC
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