15
External Devices —
The 38AU control transformers provide 24--v NEC Class 2
pow er sou rces to ener gize external control devices. These
devices will include the indoor fan motor contactor (or
contro l relay). Thes e devices may also include liquid line
solenoid valve, economizer control relay, supplemental
electric heater con tactor s or contro l relays and other devices
selected by system designer .
Control transformer TRAN1 provides control power through
terminal R to C o n the field conn ectio n terminal strip TB for
supply fan motor interlock. This source may also be used to
energize economizer contro l relay and electric heater
contactors or relays. Maximum available power is 20 va.
Check con cur r ent loadin g s b y external contro l devices. If the
maximum concur ren t loading exceeds 20 va, purch as e and
inst all the access o ry T r ans f o rmer--Relay package (available
for 208/230 and 460--v units).
Table 7 – Electrical Data — 38AUZD/E08 60 Hz Units
WITH POWERE D CONVENIENCE OUTLET
UNIT V --- P h --- H z
VOLTAGE
RANGE
}
COMPRESSOR OFM (ea)
POWER
SUPPLY
DISCONNECT SIZE
MIN MAX RLA LRA QTY FLA MCA MOCP FLA LRA
38AUZD/E08
208/230--- 3--- 60 187 253 24.0 186 2 1.5 38 60 37 197
4 6 0 --- 3 --- 6 0 414 506 12.6 100 2 0.8 20 30 19 106
5 7 5 --- 3 --- 6 0 518 633 9.9 78 2 0.7 16 25 15 84
WITHOUT POWERED CONVENIENCE OUTLET
UNIT V --- P h --- H z
VOLTAGE
RANGE
}
COMPRESSOR OFM (ea)
POWER
SUPPLY
DISCONNECT SIZE
MIN MAX RLA LRA QTY FLA MCA MOCP FLA LRA
38AUZD/E08
208/230--- 3--- 60 187 253 24.0 186 2 1.5 33 50 31 192
4 6 0 --- 3 --- 6 0 414 506 12.6 100 2 0.8 18 25 16 104
5 7 5 --- 3 --- 6 0 518 633 9.9 78 2 0.6 14 20 13 82
Legend and Notes for Table 7
LEGEND:
F L A --- F u l l L o a d A m p s
LRA --- Locked Rotor Amps
MOCP --- Maximum Over Current
Protection
NEC --- National Electrical Code
RLA --- Rated Load Amps
}
Units are suitable for use on electrical systems where voltage
supplied to the unit terminals is not b elow or above the listed
limits.
NOTES:
1. The MCA and Fuse values are calculated in accordance with
The NEC. Article 440.
2. Motor RLA and LRA values are established in accordance
with Underwriters’ Laboratories (UL). Standard 1995.
3 . T h e 5 7 5 --- v u n i t s a r e U L , C a n a d a --- l i s t e d o n l y .
4. Unbalanced 3-Phase Supply Voltage
Never operate a motor where a phase imbalance in supply
voltage is greater than 2%. Use the following formula to de-
termine the percentage of voltage imbalance.
Example: Supply voltage is 230-3-60
% Voltage Imbalance = 100 x
max voltage deviation from average voltage
average voltage
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
maximum allowable 2%.
IMPORTANT: If the supp ly voltage phase imbalance is more than
2%, contact your local electric utility company immediately.
38AU
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