Bryant DURAPAC 551B - Manual (Page 70)

70
LEGEND AND NOTES FOR ELECTRICAL DATA TABLES PAGES 65-69
LEGEND
*Heater capacity (kW) is based on heater voltage of 208 v, 240 v,
480 v, and 600 v. Heaters are rated at 240 v, 480 v, or 600 v. If power
distribution voltage to unit varies from rated heater voltage, heater kW
will vary accordingly. To determine heater capacity at actual unit volt-
age, multiply 240 v, 480 v, or 600 v capacity by multipliers found in
table on page 64.
†Used to determine minimum disconnect size per NEC.
**Heaters are field installed only.
††Fuse or HACR circuit breaker.
||Fusing in single point box provides the required branch circuit
protection.
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. The
Canadian units may be fuse or circuit 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
of voltage imbalance.
% Voltage Imbalance
Example: Supply voltage is 460-3-60.
AB = 452 v
BC = 464 v
AC = 455 v
= 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
maximum allowable 2%.
IMPORTANT: If the supply voltage phase imbalance is more than
2%, contact your local electric utility company immediately.
FLA — Full Load Amps
HACR — Heating, Air Conditioning and Refrigeration
IFM
— Indoor (Evaporator) Fan Motor
LRA — Locked Rotor Amps
MCA — Minimum Circuit Amps
MOCP— Maximum Overcurrent Protection
NEC — National Electrical Code
OFM — Outdoor (Condenser) Fan Motor
RLA
— Rated Load Amps
= 100 x
max voltage deviation from average voltage
average voltage
Average Voltage =
452 + 464 + 455
3
=
1371
3
7
457
0TF
Q
00
4-
01
2
55
8F0
36-
15
0