FRICK
®
QUANTUM
™
LX/HD RETROFIT
INSTALLATION INSTRUCTIONS
090.040-I (MAR 2012)
Page 9
generated between the VFD output and the motor, relative
to a conventional starter. If these grounds are left coupled
by a common back-plate in the starter/drive, this noise can
be direct coupled to the control power, analog device, and
communications grounding and may cause unexplained
behavior and possible damage to components.
To install correctly, run a separate, properly sized (typically 10
or 8 AWG) insulated wire to ground along with the 3-phase
ground to the 3-phase supply transformer (plant). This will
require that the 3-phase ground and the control power
ground be electrically isolated except for the connection at
the plant supply transformer.
This style of grounding should steer the noise (EMI/RFI)
to earth ground, reducing the potential for it to affect the
sensitive equipment, which could occur if the grounds
were left coupled.
NOTE: If all other recommendations
for grounding are followed, this process should not be
necessary.
CONDUIT
All national and local codes must be followed for conduit
with regard to materials, spacing and grounding. In addition,
Johnson Controls-Frick requirements must be followed
where they exceed or match national or local codes.
Conversely, there is no allowance for any practices that are
substandard to what is required by national or local codes.
Johnson Controls-Frick conduit requirements:
•
For
variable frequency drives
(VFDs) of any type, threaded
metallic or threaded PVC-coated metallic is required
for both the power feed (line side) from the source and
between the VFD output and the motor (load side).
•
Regardless of horsepower, both the incoming 3-phase
power to the drive input terminals and the outgoing PWM
(pulse width modulated) power from the output terminals
of the drive to the motor will be run in separate conduits
that will be grounded.
•
Under no circumstances regardless of horsepower, will the
incoming 3-phase power to the drive be mixed or ran in
the same conduit, wire duct or any other style of enclosure
with the outgoing PWM power from the drive output to
the motor.
•
PVC conduit is acceptable
only
when
VFD rated cable
of
the proper conductor size and ground is used. This applies
to both the line side and load side of the drive. When VFD
rated cable is not used, threaded metallic or threaded
PVC-coated metallic must be used.
•
When threaded metallic or threaded PVC-coated metallic
is used, it must be grounded at both ends.
•
When not required to be in metal or other material by
national or local codes, conduits for the power feed
(3-phase) of constant speed starters may be PVC.
•
When not required to be in metal or other material by
national or local codes, conduits between a constant speed
starter and the motor (3-phase) may be PVC.
•
Any unshielded control voltage, signal, analog, or
communication wiring that does not maintain 12 inches
of separation from any 3-phase conductors for every 33
feet (10 meters) of parallel run must be in metal conduit
which will be grounded.
Separation: (0-33 feet, 0-10 meters – 12 inches, .3 meters),
(33-66 feet, 10-20 meters – 24 inches, .6 meters)
•
Since PVC conduit does absolutely nothing to protect lower
voltage lines from the magnetic field effects of higher
voltage conductors, running either the lower or the higher
voltage lines in PVC, does not reduce these requirements
on separation. Only running in metal conduit can relieve
these requirements.
•
Due to the level of EMI that can be induced onto lower
voltage lines when running multiple feeders in a trench,
control power, communications, analog, or signal wiring
cannot be run in trenches that house multiple conduits/
electrical ducts carrying 3-phase power to starters/vfd or
motors.
•
Control power, communications, analog, or signal wiring
should be run overhead (preferred) or in a separate trench.
If these lines are not in threaded metallic or threaded PVC-
coated metallic, abiding by the separation requirements
noted above is necessary.
•
Though not recommended, if cable trays are used,
metallic
dividers must be used for separation of conductors of
unlike voltages and types (AC or DC).
NOTE: When in doubt contact the factory or use threaded
metallic or threaded PVC coated metallic conduit.
WIRING PRACTICES
Do not mix wires of different voltages in the same conduit.
An example of this would be the installation of a screw
compressor package where the motor voltage is 480 volts
and the electronic control panel power is 120 volts. The 480
volt circuit must be run from the motor starter to the motor
in its own conduit. The 120 volt circuit must be run from the
motor starter control transformer to the electronic control
panel in its own separate conduit. If the two circuits are run
in the same conduit, transients on the 480 volt circuit will be
induced onto the 120 volt circuit causing functional problems
with the electronic control panel. Metallic dividers must be
used in wire way systems (conduit trays) to separate unlike
voltages. The same rule applies for 120 volt wires and 220
volt wires. Also, never run low voltage wires for DC analog
devices or serial communications in the same conduit with
any AC wiring including 120 volt wires. See Figure 4.
Figure 4
