Mitsubishi Electric PAC-MK34BC, Техническое и сервисное руководство

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16
OCH744
<Output pulse signal and the valve operation>
(2) Linear expansion valve operation
A
B
Open
Extra tightening (about 32 pulse)
Pulse number
500 pulse
Opening a valve
all the way
Close
Valve position (capacity)
Close
Open
The output pulse shifts in the following order.
Opening a valve: 8 → 7 → 6 → 5 → 4 → 3 → 2 → 1 → 8
Closing a valve: 1 → 2 → 3 → 4 → 5 → 6 → 7 → 8 → 1
• When linear expansion valve operation stops, all output phases
become OFF.
• When the power is turned on, 700 pulse closing valve signal will be
sent till it goes to
A
point in order to define the valve position.
(The pulse signal is being sent for about 20 seconds.)
• When the valve moves smoothly, there is no sound or vibration
occurring from the linear expansion valve: however, when the pulse
number moves from
B
to
A
or when the valve is locked, sound can
be heard.
No sound is heard when the pulse number moves from
B
to
A
in
case coil is burnt out or motor is locked by open-phase.
• Sound can be detected by placing the ear against the screw driver
handle while putting the screw driver to the linear expansion valve.
Linear expansion valve
(1) Operation summary of the linear expansion valve
• Linear expansion valve opens/closes through stepping motor after receiving the pulse signal from the branch box controller
board.
• Valve position can be changed in proportion to the number of pulse signal.
<Connection between the branch box controller board and the linear expansion valve>
1
ON
OFF
OFF
OFF
ON
ON
OFF
OFF
OFF
ON
OFF
OFF
OFF
ON
ON
OFF
ø1
Output
(Phase)
Output
ø2
ø3
ø4
2 3 4 5 6 7 8
OFF
OFF
ON
OFF
OFF
OFF
ON
ON
OFF
OFF
OFF
ON
ON
OFF
OFF
ON
(LEV) in Branch box
LEV
M
1
5
ø4
ø4
ø3
ø2
ø1
1 Red
Blue
Orange
Yellow
White
2
3
4
5
Connector LEV-A
LEV-B
LEV-C
LEV-D
LEV-E
12 VDC
branch box controller board
Drive circuit
ø3
ø2
ø1
2
1
4
3