Current Cut - Mitsubishi Heavy Industries SRK20ZD-S1 Technical Manual

(g) Inspection procedures corresponding to detail of trouble
Sensor error
Is connector connection good?
YES
Is sensor resistance value good?
YES
Replace PCB.
◆ Discharge pipe sensor temperature characteristics
Temperature (˚C) Resistance (kΩ)
0
5
10
15
20
25
30
35
40
45
50
55
60
65

Current cut

Does current cut operate when
operating inverter with compressor
wire disconnected?
YES
Is output voltage applied to all 3
phases of power transistor?
YES
Is there any shortcircuit?
YES
Inspect compressor.
NO
Correct connection.
NO
Temperature (˚C) Resistance (kΩ)
164 70
127 75
99 80
78 85
62 90
50 95
40 100
32 105
26 110
21 115
17 120
14 125
12 130
10 135
NO
Defective inverter
NO
Defective inverter
NO
Secure space for suction
and blow out.
¡ Check compressor wiring visually.
¡ Check insulation resistance. (1 MΩ or over)
¡ Check coil wire resistance. (Few Ω)
Replace sensor.
◆ Sensor temperature characteristics
(Room temp., indoor unit heat exchanger
temp., outdoor unit heat exchanger
temp., outdoor air temp.)
8.7
7.3
6.2
5.3
(Broken wire)
4.5
3.9
3.3
2.9
2.5
2.2
1.9
(Shortcircuit)
1.6
1.4
1.3
If check results are normal,
compressor is locked.
47
- -
[Broken sensor wire,
connector poor connection]
30
25
20
15
10
5
–10 0 10 20 30 40
Temperature (˚C)
[Open phase on compressor output
terminal, compressor lock]
50 60 70