Safety And Protective Devices; Table 2-1 Safety And Protective Devices - Carrier 69NT40-511-300 Operation And Service

i i. Humidity Sensor Humidity Sensor
j. Controller

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.
Open safety switch contacts on either or both of devices
UNSAFE CONDITION
Excessive current draw
Excessive current draw in the
control circuit
Excessive current draw by the
controller
Excessive current draw by the
emergency defrost circuit
Excessive condenser fan mo-
tor winding temperature
Excessive compressor motor
winding temperature
Excessive evaporator fan mo-
tor(s) winding temperature
Abnormal pressures/tempera-
tures in the high refrigerant
side
Abnormally high discharge
pressure
Orange wire
Red wire
Brown wire
Input voltage
Output voltage
Output voltage readings verses relative humidity (RH) percentage:
30%
50%
70%
90%
Setpoint Range

Table 2-1 Safety and Protective Devices

SAFETY DEVICE
Circuit Breaker (CB-1) -- Manual Reset
Circuit Breaker (CB-2, 50 amp) --Manual Reset
Circuit Breaker (CB-2, 70 amp) --Manual Reset
Fuse (F3)
Fuse (F1 & F2)
Fuse (FED)
Internal Protector (IP-CM) -- Automatic Reset
Internal Protector (IP-CP) -- Automatic Reset
Internal Protector(s) (IP-EM) -- Automatic Reset
Fusible Plug -- Used on the Receiver
Rupture Disc -- Used on the Water-Cooled Con-
denser
High Pressure Switch (HPS)
Ground
0 to 3.3 vdc
--30 to +30 _C (--22 to +86 _F)
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).
2-9
Power
Output
5 vdc
0.99 V
1.65 V
2.31 V
2.97 V
DEVICE SETTING
Trips at 29 amps (460 vac)
Trips at 62.5 amps (230 vac)
Trips at 87.5 amps (230 vac)
10 amp rating
5 amp rating
5 amp rating
N/A
N/A
N/A
99 _C = (210 _F)
35 kg/cm@ = (500 psig)
Opens at 25 kg/cm@
(350 psig)
T-285