Mitsubishi Heavy Industries 112KXE6, Service Manual, Page: 15 / 209

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(3) Compressor control
(a) 4-way valve switching safeguard
In order to switch 4-way valve completely, it makes the compressor speed increasing as follows.
(i)
This control starts to increase the compressor speed from 10Hz after the compressor pre-start control ends.
(ii) The target compressor speed is shown in following table.
(b) Compressor protection start
After the 4-way valve switching safeguard, the compressor is controlled with the following compressor protection start.
➀
Compressor protection start, normal
➁
Compressor protection start A
➂
Compressor protection start B
(i) Compressor protection start, normal
< Control contents >
Compressor maintains operation at lower limit frequency, after 4-way valve switching safeguard ends.
(During this control, compressor speed is prohibited to increase.)
After this control ends, comperssor speed is governed by the compressor speed control.
< End conditions >
When either one of the following conditions is established
a)
When it has elapsed 1 minute and 45 seconds after the start
(ii) Compressor protection start A
< Control contents >
➀
Compressor maintains operation at lower limit frequency, after 4-way valve switching safeguard ends.
If the time from starting till reaching the lower limit frequency after 4-way valve switching safeguard operation
has elapsed 1minute, the target frequency is changed to that of 1minute later from the lower limit frequency.
➁
During this control, the target frequency is increased at a rate of 5Hz/minute from the lower limit frequency.
(Note) The starting point of this control is the completion point of inverter start (10Hz).
Item
Model
4-way valve switching safeguard/Target compressor speed
Frequency (Fk) Speed (rps)
FDC224KXE6
70 50
FDC280KXE6
FDC335KXE6
71 42
Initial start remote
controller ON
error reset
Thermostat ON start
Operation mode
is changed during
thermostat OFF
Operation mode is
not changed during
thermostat OFF
Compressor ON
Initial
Less than 45 min
after power ON
Compressor
protection start B
Compressor
protection start B
Compressor
protection start B
45min. or more
after power ON
Compressor
protection start A
Compressor
protection start A
Compressor
protection start A
Compressor ON
Second & later
Less than 45 min
after stop
Compressor normal
protection start
Compressor normal
protection start
Compressor normal
protection start
45min. or more
after stop
Compressor
protection start A
Compressor
protection start A
Compressor
protection start A
10 20 30 25 40 50 60 70
Lower limit frequency
Speed control
Start
Time (second)
80 90 105 120
60
40
20
10
Compressor inverter frequency (Hz)