Mitsubishi Heavy Industries FDT28KXE6A Service Manual page 19

(9) Protective control
(a) Discharge pipe temperature control (Master unit/slave unit)
(i) I f the discharge pipe temperature (detected with Tho-D1, D2) exceeds the set value, it makes the compressor capacity
control performed and the solenoid valves SV1, 2 (for cooling down the compressor) open according to the compressor
Hz in order to suppress the discharge pipe temperature rising.
1) Compressor capacity control
2) Solenoid valve (SV1, 2) control for cooling down compressor.
zone B
• zone A
SV1 : OFF
SV2 : OFF
Discharge pipe temperature (°C) [Tho-D1, D2]
< ON conditions >
① In the zone A: SV1 is turned ON when Td1 > = 115°C. SV2 is turned ON when Td2 > = 115°C.
② In the zone B: SV1 is turned ON when Td1 > = 110°C. SV2 is turned ON when Td2 > = 110°C.
< OFF conditions>
① In the zone A: SV1 is turned OFF when Td1 < = 108°C. SV2 is turned OFF when Td2 > = 108°C.
② In the zone B: SV1 is turned OFF when Td1 < = 103°C. SV2 is turned OFF when Td2 < = 103°C.
(ii) D ischarge pipe temperature control and Error display
1) When the discharger temperature exceeds 130°C or higher for 2 seconds continuously, it makes the compressor
stopped. And when the discharge pipe temperature decreases to lower than 90°C, it makes the compressor restarted
automatcally.
2) If this control [mentioned in (ii)-1)] is activates 5 times within 60 minutes, it makes the compressor anomalous
stop and displays E36, In case of anomalous stop, it cannot be operated again until the discharge pipe temperature
decreases to lower than 90°C for 60 minutes continuously.
(b) Current safe control
• Current safe control is done by both Master and Slave unit individually.
< Compressor capacity control >
1) Compressor frequency is controlled by detecting the inverter primary current (T-phase) and the inverter secondary
current.
However under the following operating status ① and ② , it does not detect the inverter current.
① Actual compressor frequency N < 20Hz
② During the period that actual compressor frequency is decreasing or during the period of 1 second after the actual
compressor frequency decreased.
Reset
Discharge pipe temperature (°C) [Tho-D1, D2]
zone A
40HZ 45HZ
(33HZ) (38HZ)
ON
108 115
Compressor capacity is
reduced at 5-second intervals
Retention
110 120
Note (1) Value in ( ) are for the models FDC615, 680KXE6 and
FDC1180~1360KXE6
• zone B
SV1 : OFF
SV2 : OFF
Discharge pipe temperature (°C) [Tho-D1, D2]
17
- -
ON
103 110