Vfd Installation Recommendations - Emerson Vilter PLC Operation Manual

Section 1 • General Information

VFD Installation Recommendations

• All wiring to and from the Variable Frequency Drive
(VFD) starter shall conform to the National Fire
Protetcion Association 70 (NFPA-70), local codes and
the manufacturer's guidelines and specifi cations.
• Thoroughly read the manufacturer's VFD installation
and instruction manuals.
• In the event of a code and manufacturer recom-
mendation confl ict, always use the more stringent
standard.
• Only use an inverter duty rated motor built to NEMA
MG1 PART 30 & 31.
• Always used copper conductors to feed the VFD
starter and motor. Use cable with thermoset insula-
tion such as XLPE or XHHW-2 from the VFD to motor.
• It is preferred to use VFD cable, service wire company
or equal, between the VFD and the motor per manu-
facturer's instructions.
• It is preferred to use continuous metal conduit to the
VFD starter to the motor.
• If non-metallic conduit is used, VFD cable must be
used.
• If using VFD cable in metal conduit, the metal con-
duit must be insulated at the motor, so that the metal
conduit is not a continuous run.
• Always use fl exible metallic liquid-tight conduit to
feed the motor from metallic conduit.
• Grounding conductor must run from the VFD ground
terminals directly to the motor conduit box. Always
use proper grounding techniques (Star Method) and
sized according to the NFPA 70 NEC.
• Always use bonding bushings on all conduit ends,
• Always use bonding bushings on all conduit ends,
with proper size braided copper cable bonded to the
starter panel.
• All grounding and bonding conductors and lugs must
terminate on bare metal and not to painted surfaces.
• Always use a minimum of 3% impedance line reactor
such as MTE or equal.
• Where the cables to the motor are longer than 50',
always use a load reactor (customer must provide
Vilter with cable lengths from feeder to starter and
from starter to motor).
• Where the cables to the motor are longer than 500',
always use a DV/DT load fi lter (customer must pro-
vide Vilter with cable lengths from feeder to starter
and from starter to motor).
Blower Package PLC Operation Manual •Vilter/Emerson • 35391BLP
• Where the cables to the motor are longer than 1000',
always use a sine fi lter (customer must provide Vilter
with cable lengths from feeder to starter and from
starter to motor).
• Line and load conductors must be separated, as
much as the starter cabinet will allow, and cannot be
in the same conduit or cable chase.
• By no means shall power and control cables run in
parallel - cables must be separated, as much as the
starter cabinet will allow, and cannot be in the same
conduit or cable chase.
• For analog signals, use twisted shielded control cable
rated for 600V.
• When a generator is feeding a VFD starter, use a 5%
line reactor.
• Some countries require RFI/EMI fi lters -- please con-
sult country codes and standards.
• As an insurance policy against motor shaft currents,
use a split ring bearing protection ring on the motor
shaft with the non-load bearing insulated.
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