Carrier 69NT40-521 Safety and Protective Devices, Unsafe Condition Safety Device Device Setting

2.12 SAFETY AND PROTECTIVE DEVICES

Unit components are protected from damage by safety and protective devices listed in Table 2-1. These devices monitor the unit operating conditions and open a set of electrical contacts when an unsafe condition occurs.

Open safety switch contacts on either or both of devices

IP-CP or HPS will shut down the compressor.

Open safety switch contacts on device IP-CM will shut down the condenser fan motor.

The entire refrigeration unit will shut down if one of the following safety devices open: (a) Circuit Breaker(s);

(b)Fuse (F3/15A); or (c) Evaporator Fan Motor Internal Protector(s) - (IP-EM).

Table 2-1. Safety and Protective Devices

UNSAFE CONDITION	SAFETY DEVICE	DEVICE SETTING
	Circuit Breaker (CB-1) -- Manual Reset	Trips at 29 amps (460 vac)
Excessive current draw	Circuit Breaker (CB-2, 50 amp) --Manual	Trips at 62.5 amps (230 vac)
	Reset
	Circuit Breaker (CB-2, 70 amp) --Manual	Trips at 87.5 amps (230 vac)
	Reset
Excessive current draw on the	Fuse (F3)	15 amp rating
control circuit
Excessive current draw by the	Fuse (F1 & F2)	5 amp rating
Controller/DataCORDER
Excessive condenser fan	Internal Protector (IP-CM) -- Automatic	N/A
motor winding temperature	Reset
Excessive compressor motor	Internal Protector (IP-CP) -- Automatic	N/A
winding temperature	Reset
Excessive evaporator fan	Internal Protector(s) (IP-EM) -- Automatic	N/A
motor(s) winding temperature	Reset
Abnormal	Fusible Plug -- Used on the Receiver	93 _C = (200 _F)
pressures/temperatures in the	Rupture Disc -- Used on the Water-Cooled	35 kg/cm@ = (500 psig)
high refrigerant side	Condenser
Abnormally high discharge	High Pressure Switch (HPS)	Opens at 25 kg/cm@ (350 psig)
pressure

SECTION 2

2-19 T-268-07