Bryant LEGACY 580J User Manual
Page 45
45
Table 29 -- MCA/MOCP DETERMINATION W/ PWRD C.O. (con’t)
UN
IT
NOM.
V---Ph---Hz
IFM
TYPE
COMBUSTION
FAN MOTOR
FLA
POWER
EXHAUST
FLA
w/ PWRD C.O.
NO P.E.
w/ P.E. (pwrd fr/ unit)
MCA
MOCP
DISC. SIZE
MCA
MOCP
DISC. SIZE
FLA
LRA
FLA
LRA
580J
*28D
208/230---3---60
STD
0.52
5.9
134.0
175
140
589
145.8
175
154
609
MED
131.8
175
138
591
143.6
175
151
611
HIGH
138.4
175
145
627
150.2
175
159
647
MED---
High Eff
139.4
175
147
599
151.2
175
160
619
HIGH---
High Eff
152.1
200
161
673
163.9
200
175
693
460---3---60
STD
0.3
3.1
55.1
60
58
301
61.3
70
65
313
MED
54.1
60
57
302
60.3
70
64
314
HIGH
57.4
70
61
320
63.6
80
68
332
MED---
High Eff
57.9
70
61
306
64.1
80
68
318
HIGH---
High Eff
63.9
80
68
343
70.1
80
75
355
575---3---60
STD
0.24
2.4
42.8
50
45
246
47.6
60
50
254
MED
42.3
50
44
235
47.1
60
50
243
HIGH
45.0
50
47
261
49.8
60
53
269
MED---
High Eff
46.2
60
49
244
51.0
60
54
252
HIGH---
High Eff
46.7
60
49
271
51.5
60
55
279
LEGEND:
C.O.
--- Convenient outlet
DISC
--- Disconnect
FLA
--- Full load amps
IFM
--- Indoor fan motor
LRA
--- Locked rotor amps
MCA
--- Minimum circuit amps
MOCP
--- Maximum over current protection
P.E.
--- Power exhaust
UNPWRD CO
--- Unpowered convenient outlet
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 break-
er.
2.
Unbalanced 3-Phase Supply Voltage
Never operate a motor where a phase imbalance in supply volt-
age is greater than 2%. Use the following formula to determine
the percentage of voltage imbalance.
% Voltage Imbalance
= 100 x
max voltage deviation from average voltage
average voltage
Example: Supply voltage is 230-3-60
AB = 224 v
BC = 231 v
AC = 226 v
Average Voltage =
(224 + 231 + 226)
=
681
3
3
=
227
Determine maximum deviation from average voltage.
(AB) 227 – 224 = 3 v
(BC) 231 – 227 = 4 v
(AC) 227 – 226 = 1 v
Maximum deviation is 4 v.
Determine percent of voltage imbalance.
% Voltage Imbalance
= 100 x
4
227
= 1.76%
This amount of phase imbalance is satisfactory as it is below the maxi-
mum allowable 2%.
IMPORTANT: If the supply voltage phase imbalance is more than 2%,
contact your local electric utility company immediately.
580J