Carrier 50HJQ004 Installation, Start-Up And Service Instructions Manual page 15

LEGEND
FLA --- Full Load Amps
HACR --- Heating, Air Conditioning and Refrigeration
IFM --- Indoor ---Fan Motor
LRA --- Locked Rotor Amps
MCA --- Minimum Circuit Amps
MOCP --- Maximum Overcurrent Protection
NEC --- National Electrical Code
OFM --- Outdoor ---Fan Motor
RLA --- Rated Load Amps
*Heater capacity (kW) is based on heater voltage of 208 v, 240 v, or 480 v.
If power distribution voltage to unit varies from rated heater voltage,
heater kW will vary accordingly.
†Heaters are field installed only.
**Fuse or HACR circuit breaker.
††Electrical disconnect cannot be used if electric heater is installed.
NOTES:
1. In compliance with NEC requirements for multimotor and combina-
tion load equipment (refer to NEC Articles 430 and 440), the overcur-
rent protective device for the unit shall be fuse or HACR breaker.
2. 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 percent-
age of voltage imbalance.
% Voltage Imbalance
= 100 x max voltage deviation from average voltage
average voltage
Example: Supply voltage is 460-3-60
AB = 452 v
BC = 464 v
AC = 455 v
452 + 464 + 455
Average Voltage
=
3
1371
=
3
= 457
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 maxi-
mum allowable 2%.
IMPORTANT: If the supply voltage phase imbalance is more
than 2%,contact your local electric utility company immediately.
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