Carrier 50HX Installation, Start-Up, And Operating Instructions Manual page 18

LEGEND
FLA — Full Load Amps
LRA — Locked Rotor Amps
MCA — Minimum Circuit Amps
MOCP — Maximum Overcurrent Protection
RLA — Rated Load Amps
CKT BKR — Circuit Breaker
NOTES:
1. In compliance with NEC (National Electrical Code) requirements
for multimotor and combination load equipment (refer to NEC
Articles 430 and 440), the overcurrent protective device for the
unit shall be Power Supply fuse . Canadian units may be
fuse or circuit breaker.
2. Minimum wire size is based on 60 C copper wire. If other than
60 C wire is used, or if length exceeds wire length in table,
determine size from NEC.
3. Unbalanced 3-Phase Supply Voltage
Never operate a motor where a phase imbalance in supply volt-
age is greater than 2%. Use the following formula to determine
the percentage of voltage imbalance.
% Voltage imbalance
max voltage deviation from average voltage
= 100 x
average voltage
®
C
O
R
G
Y
E
W2
THERMOSTAT UNIT CONTROL POWER
AND SUBBASE
Fig. 23—Control-Voltage Connections
18
EXAMPLE: Supply voltage is 460-3-60.
AB = 452 v
BC = 464 v
AC = 455 v
Average Voltage =
Determine maximum deviation from average voltage.
(AB) 457 452 = 5 v
(BC) 464 457 = 7 v
(AC) 457 455 = 2 v
Maximum deviation is 7 v.
Determine percent of voltage imbalance.
% Voltage Imbalance = 100 x
= 1.53%
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.
BRN
ORN
RED
GRN
YEL
WHT
SPLICE BOX
452 + 464 + 455
3
1371
=
3
= 457
7
457
C99024
C99056