Carrier SINGLE PACKAGE ROOFTOP UNITS 48PG20-28 Installation And Service Instructions Manual page 15

LEGEND
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
*Fuse or HACR circuit breaker.
NOTES:
1. In compliance with NEC requirements for multimotor and com-
bination 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 volt-
age is greater than 2%. Use the following formula to determine
the percent voltage imbalance.
% Voltage Imbalance
= 100 x max voltage deviation from average voltage
average voltage
TOP HOOD
SECTION
SEAL
STRIP
LOCATION
BOTTOM
HOOD
SECTION
FILTER
RETAINER
NOTE: Units with manual damper only use one filter.
LEGEND AND NOTES FOR TABLES 4A AND 4B
HOOD
SIDE
FILTER
GUIDE
FILTER
MANUAL
DAMPER
(IF EQUIPPED)
Fig. 18 — Outdoor-Air Hood Details
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%.
IMPORTANT: If the supply voltage phase imbalance is more
than 2%, contact the local electric utility company immediately.
3. The convenience outlet full load amps (FLA) are 5, 3, and 3 for
208/230, 460, 575-V units, respectively.
ADD
SEAL
STRIP
ADD
SEAL
STRIP
15
452 + 464 + 455
3
1371
=
3
= 457
7
457
INNER
FILTER
TRACK
ADD
SEAL
STRIP
ADD
SEAL
STRIP
FILTER
GUIDE
HOOD
SIDE
UNIT
BACK
PANEL