Trouble Criterion Of Main Parts; Thermistor - Mitsubishi Electric M Series Service Manual

12-6. Trouble criterion of main parts

MVZ-A12AA7
MVZ-A18AA7
MVZ-A24AA7
MVZ-A30AA7
MVZ-A36AA7
Part name
Room temperature

thermistor

(TH1)
Pipe temperature
thermistor/liquid
(TH2)
Condenser/evaporator
temperature thermistor
(TH5)
Wiring diagram
12-7. Thermistor
<Thermistor Characteristic graph>
Room temperature thermistor (TH1)
Thermistor for
Pipe temperature thermistor (TH2)
lower temperature
Condenser/evaporator temperature
thermistor (TH5)
Thermistor R = 15 k" ± 3%
0
Fixed number of B = 3480 k" ± 2%
1
Rt = 15exp { 3480(
273+t
0°C (32°F) 15 k"
10°C (50°F) 9.6 k"
20°C (68°F) 6.3 k"
25°C (77°F) 5.2 k"
30°C (86°F) 4.3 k"
40°C (104°F) 3.0 k"
Check method and criterion
Measure the resistance with a tester.
(Part temperature 10C (50F) ~ 30C (86F))
Normal
4.3k~9.6k
Vm (Power supply for motor)
Vcc (Power supply for control)
Regulator
Vsp (Speed command voltage)
PG (Pulse output for rotation)
GND
1
) }
273
36
Abnormal
Opened or short-circuited
Motor
Board with build-in motor
Hall IC
Power
device driver
Current detecting resistor
< Thermistor for lower temperature >
50
40
30
20
10
0
-20 -10 0 10 20 30 40 50
-4 14 32 50 68 86 104 122
Temperature
Motor winding
Pre
(˚C)
˚F
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