3–9 T-3543.4 SAFETY AND PROTECTIVE DEVICESUnit components are protected from damage by safety and protective devices listed in the following table. Thesedevices monitor the unit operating conditions and open a set of electrical contacts when an unsafe conditionoccurs.h. Humidity SensorOrange wire PowerRed wire OutputBrown wire GroundInput voltage 5 vdcOutput voltage 0 to 3.3 vdcOutput voltage readings verses relative humidity (RH) percentage:30% 0.99 V50% 1.65 V70% 2.31 V90% 2.97 Vi. Controller Setpoint Range -30 to +30C (-22 to +86F)Table 3–3 Safety and Protective DevicesUNSAFE CONDITION SAFETY DEVICE DEVICE SETTINGExcessive current drawCircuit Breaker (CB-1) - Manual Reset Trips at 29 amps (460 VAC)Circuit Breaker (CB-2, 50 amp) - Manual Reset Trips at 62.5 amps (230 VAC)Circuit Breaker (CB-2, 70 amp) - Manual Reset Trips at 87.5 amps (230 VAC)Excessive current draw in thecontrol circuit Fuse (F3A & F3B) 7.5 amp ratingExcessive current draw by thecontroller Fuse (F1 & F2) 5 amp ratingExcessive current draw by theemergency defrost circuit Fuse (FED) 5 amp ratingExcessive condenser fanmotor winding temperature Internal Protector (IP-CM) - Automatic Reset N/AExcessive compressor motorwinding temperature Internal Protector (IP-CP) - Automatic Reset N/AExcessive evaporator fanmotor(s) winding temperature Internal Protector(s) (IP-EM) - Automatic Reset N/AAbnormal pressures /temperatures in thehigh refrigerant sideFusible Plug - Used on the Receiver 99C = (210F)Rupture Disc - Used on theWater-Cooled Condenser 35 kg/cm = (500 psig)Abnormally high dischargepressure High Pressure Switch (HPS) Opens at 25 kg/cm(350 psig)Table 3–2 Electrical Data (Continued)
