Service manual

T -318
2-- 9
2.3 ELECTRICAL DATA (Continued)
h. Humidity Sensor
Orange wire Power
Red wire Output
Brown wire Ground
Input voltage 5vdc
Output voltage 0to3.3vdc
Output voltage readings verses relative humidity (RH) percentage:
30% 0.99 V
50% 1.65 V
70% 2.31 V
90% 2.97 V
i. Controller Setpoint Range -30to+30C(-22to+86F)
2.4 SAFETY AND PROTECTIVE DEVICES
Unit components are protected from damage by safety and protective devices listed in the following table. These
devices monitor the unit operating conditions and open a set of electrical contacts when an unsafe condition occurs.
Table 2-1 Safety and Protective Devices
UNSAFE CONDITION
SAFETY DEVICE DEVICE SETTING
Circuit Breaker (CB-1) -- Manual Reset Tripsat29amps(460VAC)
Excessive current draw Circ uit Break er (CB-2, 50 amp) --Manual Reset
T rips at 62.5 amps (230
VAC)
Circ uit Break er (CB-2, 70 amp) --Manual Reset
T rips at 87.5 amps (230
VAC)
Excessive current draw in the
control circuit
Fuse(F3A&F3B) 7.5 amp rating
Excessive current draw by the
controller
Fuse (F1 & F2) 5 amp rating
Excessive current draw by the
emergency defrost circuit
Fuse (FED) 5 amp rating
Excessive condenser fan mo-
tor winding temperature
Internal Protector (IP-CM) -- Automatic Reset N/A
Excessive compressor motor
winding temperature
Internal Protector (IP-CP) -- Automatic Reset N/A
Excessive evaporator fan mo-
tor(s) winding temperature
Internal Protector(s) (IP-EM) -- Automatic Reset N/A
Abnormal pressures/tempera-
tures in the high refrigerant
side
FusiblePlug--UsedontheReceiver
Rupture Disc -- Used on the Water-Cooled
Condenser
99 C = (210 F)
35 kg/cm@ = (500 psig)
Abnormally high discharge
pressure
High Pressure Switch (HPS)
Opens at 25 kg/cm@
(350 psig)