Carrier 48MA/50ME016-040 Installation, Start-Up And Service Instructions Manual page 11

Use the following formula to determine the percent volt-
age imbalance.
% Voltage Imbalance:
max voltage deviation from average voltage
= 100 ×
EXAMPLE: Supply voltage is 460-3-60.
AB = 452 v
BC = 464 v
AC = 455 v
Average Voltage =
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:
% Voltage Imbalance = 100 x
= 1.53%
This amount of phase imbalance is satisfactory as it is below
the maximum allowable 2%.
VOLTAGE
UNIT Voltage
RANGE
48MA (3 Ph, 60 Hz)
Min
208/230 187
016 460 414
575 518
208/230 187
024 460 414
575 518
208/230 187
028 460 414
575 518
208/230 187
030 460 414
575 518
208/230 187
034 460 414
575 518
208/230 187
040 460 414
575 518
LEGEND
COMP — Compressor
FLA — Full Load Amps
IFM — Indoor (Evaporator) Fan Motor
LRA — Locked Rotor Amps
MCA — Minimum Circuit Amps
average voltage
452 + 464 + 455
3
1371
=
3
= 457
7
457
Table 2 — Unit 48MA Electrical Data
COMP COMP
NO. 1 NO. 2
Max RLA LRA RLA
254 63.6 266
508 28.6 120 —
632 22.8 96
254 44.4 170 44.4
508 19.9 77 19.9
632 15.7 62 15.7
254 63.6 266 44.4
508 28.6 120 19.9
632 22.8 96 15.7
254 63.6 266 63.6
508 28.6 120 28.6
632 22.8 96 22.8
254 63.6 266 63.6
508 28.6 120 28.6
632 22.8 96 22.8
254 80.0 345 80.0
508 38.5 150 38.5
632 31.4 120 31.4
IMPORTANT: If the supply voltage phase imbalance
is more than 2%, contact your local electric utility com-
pany immediately.
Unit failure as a result of operation on improper line volt-
age or excessive phase imbalance constitutes abuse and may
cause damage to electrical components. See Tables 2-5 for
unit, electric heater, and 50ME electrical application elec-
trical data.
Each 50ME electric heat unit is fitted with a heating lock-
out circuit (if equipped with optional heat). If any zone mod-
ule is operating on mechanical cooling (compressor is op-
erating), the heating element in each zone module is locked
out and cannot be energized.
On 50ME units, cooling power supply wires and electric
heater power supply wires (if applicable) must be sized ac-
cording to the cooling MCA (Minimum Circuit Amps) val-
ues and heating MCA values shown on unit nameplate and
in Tables 3-5. These wires may be powered by a common
power supply (i.e., a pull-box junction), if desired. The com-
mon power supply wires from the main power source to the
junction must be sized according to the common MCA val-
ues shown in Table 5.
UNIT COMMON FEED MINIMUM CIRCUIT AMPS —
The unit common feed MCA is calculated on the basis of
either: the sum of the cooling MCA plus
units with 2 heating elements per zone module (or
ing MCA on units with 3 heating elements per zone module)
or the sum of the evaporator fan motor full load amps, per
NEC, plus the full heating MCA, whichever is larger. Field
wiring must conform to NEC limitations for Type T wire.
OFM
FLA
LRA No. 1 No. 2 No. 3
6.6
— 6.2 3.0 —
2.4
170 6.6
77 6.2 3.0 —
62 2.4
170 6.6
77 6.2 3.0 —
62 2.4
266 6.6
120 6.2 3.0 —
96 2.4
266 6.6 6.6
120 6.2 3.0 3.0
96 2.4 2.4
345 6.6 6.6
150 6.2 3.0 3.0
120 2.4 2.4
MOCP — Maximum Overcurrent Protection
OFM — Outdoor (Condenser) Fan Motor
RLA — Rated Load Amps
NOTES:
1. Combustion air fan is a 115-1-60 motor on all units.
2. Condenser fan motor no. 1 is a 208/230-1-60 speed control motor
on all units.
11
1 ⁄ heating MCA on
2
COMBUSTION
IFM
FAN MOTOR
FLA Hp FLA
16.2
1.8 5 6.6
5.6
24.2
1.8 7.5 11.0
9.0
30.8
1.8 10 13.0
10.5
30.8
1.8 10 13.0
10.5
15 46.2
20 61.0
15 21.0
1.8
20 26.6
15 16.0
20 21.3
15 46.2
20 61.0
15 21.0
1.8
20 27.0
15 16.0
20 21.3
⁄ heat-
2
3
POWER
SUPPLY
MCA MOCP
109.6 125
49.8 60
39.8 45
137.5 150
62.2 70
49.4 60
168.1 200
76.1 90
60.4 70
187.3 200
84.5 100
67.5 90
210.8 225
224.6 250
94.5 100
100.5 125
75.6 90
80.6 100
247.7 300
261.5 300
116.7 150
122.7 150
95 125
100 125