Mitsubishi Heavy Industries SRC25ZMP-S Technical Manual page 38

(i) Compressor overheat protection
(i) Purpose: It is designed to prevent deterioration of oil, burnout of motor coil and other trouble resulting from the com-
pressor overheat.
(ii) Detail of operation
1) Speeds are controlled with temperature detected by the sensor mounted on the discharge pipe.
(Example) Fuzzy
Notes (1) When the discharge pipe temperature is in the range of 100 to 110 ºC, the speed is reduced by 4 rps.
(2) When the discharge pipe temperature is raised and continues operation for 20 seconds without changing, then the speed is reduced again by 4 rps.
(3) If the discharge pipe temperature is in the range of 90~100ºC even when the compressor command speed is maintained for 60 second when the
temperature is in the range of 90~100ºC, the speed is raised by 1 rps and kept at that speed for 60 second. This process is repeated until the com-
mand speed is reached.
(4) Lower limit speed
Models SRK25, 35, 45
2) If the temperature of 110ºC is detected by the sensor on the discharge pipe, then the compressor will stop immediately.
When the discharge pipe temperature drops and the time delay of 3 minutes is over, the unit starts again within 1 hour
but there is no start at the third time.
(j) Current safe
(i) Purpose: Current is controlled not to exceed the upper limit of the setting operation current.
(ii) Detail of operation: Input current to the converter is monitored with the current sensor fixed on the printed circuit board
(k) Current cut
(i) Purpose: Inverter is protected from overcurrent.
(ii) Detail of operation: Output current from the converter is monitored with a shunt resistor and, if the current exceeds the
(l) Outdoor unit failure
This is a function for determining when there is trouble with the outdoor unit during air conditioning.
The compressor is stopped if any one of the following in item (i), (ii) is satisfied. Once the unit is stopped by this function, it is not
restarted.
(i) When the input current is measured at 1 A or less for 3 continuous minutes or more.
(ii) If the compressor command sends a 0 rps signal to the indoor unit 3 times or more within 20 minutes of the power being
turned on.
(m) Indoor fan motor protection
When the air conditioner is operating and the indoor fan motor is turned ON, if the indoor fan motor has operated at 300 min
or under for more than 30 seconds, the unit enters first in the stop mode and then stops the entire system.
After lapse of 60 seconds. or over
After lapse of 60 seconds. or over
After lapse of 60 seconds. or over
90
Discharge pipe temperature (˚C)
Cooling Heating
20 rps 30 rps
of the outdoor unit and, if the operation current value reaches the limiting current value, the compressor
command speed is reduced.
If the mechanism is actuated when the speed of compressor command is less than 30 rps, the
compressor is stopped immediately. Operation starts again after a delay time of 3 minutes.
setting value, the compressor is stopped immediately. Operation starts again after a delay time of
3 minutes.
-
(3)
(3)
(4)
Lower limit
(3)
100
37
-
'13 • SRK-T-140
(1)
4 rps
4 rps
0 rps
110
-1