Carrier FAS072 Installation, Start-Up And Service Instructions Manual page 20

Legend and Notes for Tables 10-13
LEGEND
FLA — Full Load Amps
HACR — Heating, Air Conditioning, and Refrigeration
* Motors are designed for satisfactory operation within 10% of normal
voltage shown. Voltages should not exceed the limits shown in the Volt-
age Limits column.
NOTES:
1. Minimum circuit amps (MCA) and maximum overcurrent protection
(MOCP) values are calculated in accordance with The NEC. Article
440.
2. Motor FLA values are established in accordance with Underwriters'
Laboratories (UL). Standard 1995.
3. Unbalanced 3-Phase Supply Voltage
Never operate a motor where a phase imbalance in supply voltage
is greater than 2%. Use the formula in the example (see column to
the right) to determine the percentage of voltage imbalance.
4. Installation with Accessory Electric Heaters
Size the Field Power Wiring between the heater TB1 and the
FAS/FHS indoor fan motor per NEC Article 430-28 (1) or (2)
(depends on length of conduit between heater enclosure and
FAS/FHS power entry location). Install wires in field-installed
conduit.
20
Example: Supply voltage is 230-3-60
%Voltage
Imbalance:
A
MOTOR
Average Voltage
Determine maximum deviation from average voltage.
(AB) 397-393 = 4 v
(BC) 403-397 = 6 v
(AC) 397-396 = 1 v
Maximum deviation is 4 v.
Determine percent of voltage imbalance.
% Voltage Imbalance = 100x
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.
Specifications subject to change without notice.
max voltage deviation from average voltage
= 100 x
AB = 394 v
C
B
BC = 403 v
AC = 396 v
(393 + 403 + 396)
=
3
= 397
6
397
= 1.5
FAS-FHS-072-180-01SI Rev. A
average voltage
1192
=
3