Bryant 551J Series, Руководство по установке

Страница: 16 / 56

16
C12278
Fig. 18 -- Location of Non--Fused Disconnect Enclosure
To field install the NFD shaft and handle:
1. Remove the unit front panel (see Fig. 2 or Fig. 3).
2. Remove (3) hex screws on the NFD enclosure -- (2) on
the face of the cover and (1) on the left side cover. See
Fig. 19.
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.
6. Measure from the tip of the shaft to the top surface of
the black pointer; the measurement should be 3.75 to
3.88 in. (95 to 99 mm).
7. Tighten the locking screw to secure the shaft to the
NFD.
8. Turn the handle to the OFF position with red arrow
pointing at OFF.
9. Install the handle on to the painted cover horizontally
with the red arrow pointing to the left.
10. Secure the handle to the painted cover with (2) screws
and lock washers supplied.
11. Engaging the shaft into the handle socket, re--install
(3) hex screws on the NFD enclosure.
12. Re--install the unit front panel.
C12279
Fig. 20 -- Handle and Shaft Assembly for NFD
Units Without Factory--Installed
Non--Fused Disconnect —
When installing units, provide a disconnect switch per NEC
(National 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 cabinet.
All Units —
All field wiring must comply with NEC and all local codes.
Size wire based on MCA (Minimum Circuit Amps) on the
unit informative plate. See Fig. 16 and the unit label
diagram for power wiring connections to the unit power
terminal blocks and equipment ground. Maximum wire size
is #4 ga AWG (copper only) per pole on contactors and
#2ga AWG (copper only) per pole on optional non--fused
disconnect.
Provide a ground--fault and short--circuit over--current
protection device (fuse or breaker) per NEC Article 440
(or local codes). Refer to unit informative data plate for
MOCP (Maximum Over--current Protection) device size.
All field wiring must comply with the NEC and local
requirements.
All units except 208/230-v units are factory wired for the
voltage shown on the nameplate. If the 208/230-v unit is
to be connected to a 208-v power supply, the control
transformer must be rewired by moving the black wire
with the
1
/
4
-in. female spade connector from the 230--v
connection and moving it to the 208-v
1
/
4
-in. male
terminal on the primary side of the transformer. Refer to
unit label diagram for additional information.
Voltage to compressor terminals during operation must be
within voltage range indicated on unit nameplate. On
3--phase units, voltages between phases must be balanced
within 2% and the current within 10%. Use the formula
below to determine the percent of voltage imbalance.
% Voltage
Imbalance = 100 x
max voltage deviation from average voltage
average voltage
Example: Supply voltage is 230-3-60
AB = 224 v
BC = 231 v
AC = 226 v
Average Voltage =
(224 + 231 + 226)
=
681
= 227
3 3
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
= 1.76%
227
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 your local electric utility company immediately.
Operation on improper line voltage or excessive phase
imbalance constitutes abuse and may cause damage to