77 electrical data (cont) – Bryant 581A/B User Manual
Page 77
77
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
103
(8
1
/
2
Ton)
208/230-3-60
STD
NO
187
254
2
17.3
120.0
2
1.4
5.8
0.6
44.3
50
46
272
YES
49.1
60
52
277
HIGH
NO
10.6
49.1
60
52
316
YES
53.9
60
57
320
460-3-60
STD
NO
414
508
2
7.9
70.0
2
0.7
2.6
0.3
21.0
25
22
149
YES
23.2
30
24
151
HIGH
NO
4.8
23.2
30
24
171
YES
25.4
30
27
173
575-3-60
STD
NO
518
632
2
5.5
50.0
2
0.6
2.0
0.3
16.7
20
17
109
YES
18.4
25
19
111
HIGH
NO
2.8
18.5
25
19
126
YES
20.2
25
21
128
120
(10 Ton)
208/230-3-60
STD
NO
187
254
2
15.8
130
2
1.4
5.8
0.6
44.2
50
46
307
YES
50.2
60
52
311
ALT
NO
7.5
45.9
50
48
326
YES
51.9
60
54
330
HIGH
NO
15.0
53.4
60
57
374
YES
59.4
70
62
378
460-3-60
STD
NO
414
508
2
7.9
64
2
0.7
2.6
0.3
21.8
25
23
152
YES
27.8
30
25
154
ALT
NO
3.4
22.6
25
24
191
YES
25.3
30
26
193
HIGH
NO
7.4
26.6
30
28
185
YES
29.3
35
31
187
575-3-60
STD
NO
518
632
2
6.6
52
2
0.6
2.0
0.3
18.1
25
19
123
YES
24.1
25
21
109
ALT
NO
2.0
18.7
25
20
155
YES
24.7
25
22
141
HIGH
NO
2.8
21.9
30
23
150
YES
24.6
30
25
136
121
(10 Ton)
208/230-3-60
STD
NO
187
254
2
15.8
130
2
1.4
5.8
0.6
44.6
50
46
307
YES
49.4
60
52
312
ALT
NO
7.5
46.3
60
48
326
YES
51.1
60
54
331
HIGH
NO
15.0
53.8
60
57
374
YES
58.6
70
62
379
460-3-60
STD
NO
414
508
2
7.9
64
2
0.7
2.6
0.3
22.0
25
23
152
YES
24.2
30
25
154
ALT
NO
3.4
22.8
25
24
191
YES
25.0
30
26
193
HIGH
NO
7.4
26.8
30
28
185
YES
29.0
35
30
187
575-3-60
STD
NO
518
632
2
6.6
52
2
0.6
2.0
0.3
18.1
20
19
123
YES
19.8
25
21
125
ALT
NO
2.8
18.7
20
20
150
YES
20.4
25
22
156
HIGH
NO
3.3
21.9
25
23
155
YES
23.6
25
25
151
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
58
0
F
03
6-
15
1