Carrier 50TCQD, Installation Instructions Manual

Page: 58 / 68

58
Step 1 Step 2 Step 3
C12283
Fig. 79 -- Completing Installation of Return Air Smoke Sensor
Legend and Notes for Tables 29 and 30
LEGEND:
BRKR --- Circuit breaker
C.O. --- Convenience outlet
DISC. --- Disconnect
FLA --- Full load amps
LRA --- Locked rotor amps
MCA --- Minimum circuit amps
P.E. --- Power exhaust
Pwrd fr/ unit --- Powered from unit
PWRD C.O. --- Powered convenience outlet
UNPWR C.O. --- Unpowered convenience outlet
NOTES :
1. In compliance with NEC requirements for multimotor and combination load
equipment (refer to NEC Articles 430 and 440), the overcurrent protective device
for the unit shall be fuse or HACR breaker. Canadian units may be fuse or circuit
breaker.
2. For 208/230 v units, where one value is shown it is the same for either 208 or
230 volts.
3. Unbalanced 3-Phase Supply Voltage
Never operate a motor where a phase imbalance in supply voltage is greater
than 2%. Use the following formula to determine the percentage of voltage
imbalance.
% Voltage Imbalance = 100 x
max voltage deviation from average voltage
average voltage
Example: Supply voltage is 230-3-60
AB = 224 v
BC = 231 v
AC = 226 v
Average Voltage =
(224 + 231 + 226)
=
681
3 3
= 227
Determine maximum deviation from average voltage.
(AB) 227 – 224 = 3 v
(BC) 231 – 227 = 4 v
(AC) 227 – 226 = 1 v
Maximum deviation is 4 v.
Determine percent of voltage imbalance.
% Voltage Imbalance = 100 x
4
227
= 1.76%
This amount of phase imbalance is satisfactory as it is below the maximum
allowable 2%.
IMPORTANT : If the supply voltage phase imbalance is more than 2%, contact
your local electric utility company immediately.