Carrier 50HCQ12, Руководство по установке

Страница: 16 / 48

16
NOTE: TEST LEADS — Unit may be equipped with short test
leads (pigtails) on the field line connection points on contactor C
or optional disconnect switch. These leads are for factory-run test
purposes only; remove and discard before connecting field power
wires to unit connection points. Make field power connections di -
rectly to line connection pressure lugs only.
Fig. 27 — Disconnect Switch and Unit
ALL UNITS
All field wiring must comply with NEC and all local codes.
Size wire based on MCA (Minimum Circuit Amps) on the unit in -
formative plate. See Fig. 26 and the unit label diagram for power
wiring connections to the unit power terminal blocks and equip -
ment ground. Maximum wire size is #2/0 AWG AWG (copper on -
ly) per pole.
Provide a ground fault and short circuit over-current protection de -
vice (fuse or breaker) per NEC Article 440 (or local codes). Refer
to unit informative data plate for MOCP (Maximum Over-Current
Protection) device size.
Voltage to compressor terminals during operation must be within
voltage range indicated on unit nameplate. On 3-phase units, volt -
ages between phases must be balanced within 2% and the current
within 10%. Use the formula shown in the following example to
determine the percent of voltage imbalance.
Example: Supply voltage is 230-3-60
AB = 224 v
BC = 231 v
AC = 226 v
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.
This amount of phase imbalance is satisfactory as it is below the
maximum allowable 2%.
Operation on improper line voltage or excessive phase imbalance
constitutes abuse and may cause damage to electrical components.
Such operation would invalidate any applicable Carrier warranty.
NOTE: Check all factory and field electrical connections for tight -
ness.
UNITS WITHOUT FACTORY-INSTALLED NON-FUSED
DISCONNECT
When installing units, provide a disconnect switch per NEC (Na
-
tional Electrical Code) of adequate size. Disconnect sizing data is
provided on the unit informative plate. Locate on unit cabinet or
within sight of the unit per national or local codes. Do not cover
unit informative plate if mounting the disconnect on the unit cabi -
net.
UNITS WITH FACTORY-INSTALLED NON-FUSED
DISCONNECT
The factory-installed optional disconnect switch is located in a
weatherproof enclosure located under the main control box. The
manual switch handle is accessible through an opening in the ac -
cess panel. Discard the factory test leads (see Fig. 28). The factory
disconnect is 80A disconnect.
Fig. 28 — Location of Non-Fused Disconnect
Enclosure
To field install the NFD shaft and handle (Fig. 29):
1. Remove the unit front panel (see Fig. 2).
2. Remove (3) hex screws on the NFD enclosure - (2) on the
face of the cover and (1) on the bottom.
3. Remove the front cover of the NFD enclosure.
4. Make sure the NFD shipped from the factory is at OFF
position (the arrow on the black handle knob is at OFF).
5. Insert the shaft with the cross pin on the top of the shaft in
the horizontal position.
WARNING
FIRE HAZARD
Failure to follow this warning could result in personal injury,
death, or property damage.
Do not connect aluminum wire between disconnect switch and
unit. Use only copper wire.
Average Voltage =
(224 + 231 + 226)
=
681
= 227
3 3
% Voltage Imbalance = 100 x
4
= 1.78%
227
COPPER
WIRE ONLY
ELECTRIC
DISCONNECT
SWITCH
ALUMINUM
WIRE
A B C
MOTOR
IMPORTANT: If the supply voltage phase imbalance is more
than 2%, contact your local electric utility company immedi -
ately.