beautypg.com

Bryant 548F User Manual

Page 64

background image

64

ELECTRICAL DATA (cont)

LEGEND AND NOTES FOR ELECTRICAL TABLES

LEGEND

*Heaters are field installed only.

†Used to determine minimum disconnect size per NEC.

**Heater capacity (kW) is based on heater voltage of 208 v, 240 v,

480 v, and 575 v. If power distribution voltage to unit varies from rated
heater voltage, heater kW will vary accordingly.

††Fuse or HACR circuit breaker.

***Optional disconnect switch is unavailable.

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
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 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

= 100 x

max voltage deviation from average voltage

average voltage

Average Voltage =

452 + 464 + 455

3

=

1371

3

7
457

50

T

F

Q

0

04

-0

12

5

48F

036

-1

20

This manual is related to the following products: