Carrier 38AK024-044 - Field Connections; Main Power; 24-v Control Power; Control Circuit Interlock

4. Maximum field wire sizes allowed by lugs on terminal UNBALANCED 3-PHASE SUPPLY VOLTAGE —
block are: Never operate a motor where a phase imbalance in supply
350 MCM for models 38AK028 (208/230-3-60), voltage is greater than 2%. Use the following formula to
38AK034 (208 /230-3-60, 230-3-50), and determine the % voltage imbalance:
38AK044 (208/ 230-3-60, 230-3-50)
2/0 AWG for all other models.
5. Terminals for field power supply are suitable for
copper, copper-clad aluminum or aluminum conduc-
96 Voltage Imbalance
max voltage deviation from average voltage
tors. Insulation must be rated 167 F (75 C) minimum. = НЮ average voltage
CONDENSER FANS — The fans must rotate counter- .
clockwise when viewed from above. If necessary, correct Example: Supply voltage is 240-3-60.
direction of fan rotation by interchanging any 2 power |
input
wires
at
disconnect
switch.
Affix
crankcase
һеаїег
^
B
C
AB-
243
volts
decal
(located
in
installer's
packet)
to
unit
disconnect
switch.
BC
=
236
volts
AC - 238 volts
FIELD CONNECTIONS
1. Main Power — Bring wires from the fused disconnect
switch through hole in bottom rail of unit to control Average Voltage =
box (Fig. 6, 7, 8) and connect terminals ; Г
оп line side of terminal block ТВІ (see Fig. 9).
To comply with NEC Article 440-14, the disconnect
а Ee within sight from and readily acces (AB) 243 - 239 š 4 volts
. . | (ВС) 239 - 236 = 3 volts
:2. 24-v Control Power — Units have single point power (AC) 239 - 238 = 1 volt
connections. Control circuit is directly connected inter-
nally to unit. Maximum 24-v control circuit is 3 amps.
243 + 236 + 238 = 239 volts
3
Determine maximum deviation from average voltage:
Maximum deviation is 4 volts. Determine % voltage
NOTE: For wire runs up to 50 ft. use no. 18 AWG imbalance:
insulated wire (35 C min.). For 50 to 75 ft., use no. 16
AWG insulated wire (35 C min.). For over 75 ft. use 14 » 4 _
AWG insulated wire (35 C min.). as сее
3. Control Circuit Interlock — An airflow switch may be
installed in the indoor air handler to prevent unit from
running when indoor air is not flowing. This switch (no.
HRS81JEO01) is available from Service Parts Center, or This amount of phase imbalance is satisfactory as it is
equivalentcan be field supplied. This should be electri- below the maximum allowable 2%.
cally interlocked in the control circuit, between term-
inals [ 1 | and [ 6 ] (for flow switch) on TB2. See Fig.
9 for field wiring. This is in the 1 15-v circuit. Wires must IMPORTANT: Contact your local electric utility
be run in conduit with ground wire. company immediately if the supply voltage phase
4. Transformer Connections — See unit wiring label dia- imbalance is more than 2%.
gram, notes | and 2, located behind compressor com-
partment end access door.
IMPORTANT: Ensure power to the crankcase
heater is always on (except when servicing the unit).
If circuit breakers inside unit shut down the com-
pressor and condenser fans, crankcase heater
remains on.