Bryant 551A, 558F, 551B manual ELECTRICAL DATA cont, 559F180-300

ELECTRICAL DATA (cont)

	LEGEND
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

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 voltage imbalance.

NEC — National Electrical Code

% Voltage Imbalance = 100 x

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559F180-300

OFM	—	Outdoor (Condenser) Fan Motor
RLA	—	Rated Load Amps

*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 deter- mine heater capacity at actual unit voltage, multiply 240 v, 480 v, or 600 v capac- ity by multipliers found in table on page 110.

†Fuse or HACR circuit breaker.

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. 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

max voltage deviation from average voltage

= 100 x

average voltage

EXAMPLE: Supply voltage is 460-3-60.

AB = 452 v

BC = 464 v

AC = 455 v

Average Voltage = 452 + 464 + 455

3

= 1371

3

= 457

457

= 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%, con- tact your local electric utility company immediately.

3.MCA calculation for 559F180-300 units with electric heaters over 50 kW = (1.25 x IFM amps) + (1.00 x heater FLA).

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