Bryant 581A/B Heating System User Manual


 
78
ELECTRICAL DATA (cont)
LEGEND
*Used to determine minimum disconnect per NEC.
†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. 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.
= 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.
3. For units with power exhaust: If a single power source is to be used, size wire to include
power exhaust MCA and MOCP. Check MCA and MOCP when power exhaust is powered
through the unit (must be in accordance with NEC and/or local codes). Determine the new
MCA including the power exhaust using the following formula:
MCA New = MCA unit only + MCA of Power Exhaust
For example, using a 580F060 unit with MCA = 28.9 and MOCP = 35, with
CRPWREXH030A01 power exhaust.
MCA New = 28.9 amps + 1.6 amps = 30.5 amps
If the new MCA does not exceed the published MOCP, then MOCP would not change. The
MOCP in this example is 35 amps, the MCA New is below 35, therefore the MOCP is
acceptable. If “MCA New” is larger than the published MOCP, raise the MOCP to the next
larger size. For separate power, the MOCP for the power exhaust will be 15 amps per NEC.
POWER EXHAUST ELECTRICAL DATA
*Single or three phase.
UNIT SIZE
580F
NOMINAL
V-PH-Hz
IFM
TYPE
CONV
OUTLET
VOLTAGE RANGE COMPRESSOR (each) OFM (each)
IFM
FLA
COMBUSTION
FAN MOTOR
POWER SUPPLY
MINIMUM UNIT
DISCONNECT SIZE*
Min Max Qty RLA LRA Qty FLA FLA MCA MOCP† FLA LRA
150
(12
1
/
2
Ton)
208/230-3-60
STD
NO
187 254 2 23 146 2 1.4
10.6
0.6
65.2 80 68 383
YES 71.2 80 74 387
HIGH
NO
15.0
69.6 80 73 406
YES 75.6 80 79 410
460-3-60
STD
NO
414 508 2 10.4 73 2 0.7
4.8
0.3
29.6 35 31 192
YES 35.6 40 34 194
HIGH
NO
7.4
32.2 35 34 203
YES 34.9 40 37 205
575-3-60
STD
NO
518 632 2 8.3 58.4 2 0.6
2.0
0.3
23.6 30 25 154
YES 29.6 35 27 156
HIGH
NO
2.8
25.7 30 27 163
YES 31.7 35 29 165
151
(12
1
/
2
Ton)
208/230-3-60
STD
NO
187 254 2 19 156 2 1.4
10.6
0.6
56.2 70 59 359
YES 61.0 70 65 364
HIGH
NO
15.0
60.6 70 64 378
YES 65.4 80 70 383
460-3-60
STD
NO
414 508 2 9 75 2 0.7
4.8
0.3
26.5 30 28 174
YES 28.7 35 30 176
HIGH
NO
7.4
29.1 35 31 213
YES 31.3 35 33 215
575-3-60
STD
NO
518 632 2 7.4 54 2 0.6
3.3
0.3
21.6 25 23 127
YES 23.3 30 25 129
HIGH
NO 5.6 23.7 25 25 159
YES 5.6 25.4 30 27 160
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
% Voltage Imbalance = 100 x
7
457
POWER EXHAUST
PART NO.
APPLICATION
USAGE
MCA
(230 V)
MCA
(460 V)
MCA
(575 V)
MOCP
(separate
power source
only)
CRPWREXH030A01 036-073* 1.6 N/A 0.64 15
CRPWREXH021A01 036-073 N/A 0.68 N/A 15
CRPWREXH022A01 090-151* 3.4 N/A 1.32 15
CRPWREXH023A01 090-151 N/A 1.4 N/A 15
CRPWREXH028A01 ALL* 1.7 N/A 0.68 15
CRPWREXH029A01 ALL N/A 0.7 N/A 15
580F036-151