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WIRING
1. Select a suitable location in the bottom panel of the by-
pass box to connect field-supplied power source.
2. Before drilling any hole, be sure the hole and any field-
supplied conduit fittings will not interfere with the door
or components inside the enclosure.
3. Drill the appropriate size hole and connect the field-sup-
plied conduit to the enclosure.
4. Refer to the wiring diagram supplied with the bypass and
connect the line voltage power source to the line voltage
terminals (L1, L2, L3) as shown.
5. Refer to the factory-supplied voltage warning label and
verify that the power source is correct.
6. Connect the ground wire to the grounding lug provided
on the bottom of the bypass box.
7. Refer to the VFD Wiring section, Steps 7 and 8 (page
148), to connect VFD control wiring.
START-UP AND TEST
Before applying power to the VFD Bypass and VFD, verify that
the motor overload inside the bypass has been set to the full load
amperage (FLA or RLA) as specified on the motor nameplate.
IMPORTANT: Some bypass assemblies (208/230-60,
200/230-50, 380/400/415-50) contain a multi-tap control
transformer. The line voltage tap on the control trans-
former must be adjusted to the appropriate line voltage.
Fig. 122 — VFD Bypass Safety Shutdown Modification — Bypass with 115 Volt Control Transformer
ACTUAL CONNECTION DETERMINED BY
APPLICATION VOLTAGE
230
460
H1
XF
FUSE
START
STOP
12
11
14
14
FIELD SUPPLIED
ISOLATED NC SAFETY CONTACT
(FIRE/SMOKE, HPS, ETC.)
3A MINIMUM
NOTE: Bypasses with a 115-v control transformer can be field
modified to incorporate a normally closed safety contact. This
safety contact (in addition to the VFD shutdown wiring) wires into
the fire alarm system to shut down the unit even if the unit is run-
ning in the bypass position. See Fig. 122 and 123.
1. Set the switch on the front of the bypass to the OFF
position.
2. Verify that the fan freely rotates and remove and loose
items inside the fan section.
3. Close and secure the fan access door and the bypass and
VFD covers.
4. Apply power.
5. Set the switch to the LINE position and verify that the fan
operates.
For 3-phase motors:
Place the switch back in the OFF position and carefully
open the fan access door.
Verify that the fan wheel is rotating in the proper direc-
tion. If it is not, remove power and reverse any two of the
line voltage connections in the bypass box (L1, L2, L3).
DO NOT swap the motor leads; this will cause the fan to
rotate in the reverse direction when operating from the
VFD.
6. Make sure the bypass cover is closed then apply power.
7. Set the switch to the DRIVE position and verify that the
VFD operates.
8. Press the Hand button and verify that the fan operates.
0
208
H2
H3
H4
X2
120
M
13
A1
A2
96
13
M
LEGEND
155
L2
L1
OL
95
Factory Wiring
Field Wiring
a39-3995
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