
100.210-IOM (FEB 2015)
Page 24
VYPER
™
VARIABLE SPEED DRIVE
INSTALLATION
GROUNDING
Grounding.is.the.most.important.factor.for.successful.opera-
tion.and.is.typically.the.most.overlooked...The.NEC.states.that.
control.equipment.may.be.grounded.by.using.the.rigid.conduit.
as.a.conductor..This.worked.for.the.earlier.relay.systems,.but.
it.is.in.no.way.acceptable.for.electronic.control.equipment..
Conduit.is.made.of.steel.and.is.a.poor.conductor.relative.
to.an.insulated.stranded.copper.wire..Electronic.equipment.
reacts.to.very.small.currents.and.must.have.a.proper.ground.
in. order. to. operate. properly;. therefore,. stranded. copper.
grounds.are.required.for.proper.operation..
For.proper.operation,.the.control.power.ground.circuit.must.
be.a.single.continuous.circuit.of.the.proper.sized.insulated.
stranded.conductor,.from.the.electronic.control.panel.to.the.
plant.supply.transformer.(Figure.2)..Driving.a.ground.stake.
at.the.electronic.control.may.also.cause.additional.problems.
since.other.equipment.in.the.plant.on.the.same.circuits.may.
ground.themselves.to.the.ground.stake.causing.large.ground.
flow.at.the.electronic.control.panel..Also,.running.multiple.
ground. conductors. into. the. electronic. control. panel. from.
various.locations.can.create.multiple.potentials.resulting.in.
ground.loop.currents..A.single.ground.wire.(10.AWG.or.8.
AWG).from.the.electronic.control.panel,.that.is.bonded.to.the.
control.power.neutral.at.the.secondary.side.of.the.control.
power.transformer.in.the.starter.and.then.to.the.3-phase.
ground.point,.will.yield.the.best.results.
Figure 14 - Control Power ground Circuit
NOTICE
Structural grounding can also result in multiple ground
potentials and is also a relatively poor conductor.
Therefore, this is not an acceptable method for proper
operation of electronic equipment.
There.must.be.a.ground.for.the.three-phase.power.wiring..
This.must.be.sized.in.accordance.to.the.NEC.and.any.local.
codes.relative.to.the.highest.rated.circuit.overload.protec-
tion.provided.in.the.circuit..The.manufacturer.may.require.a.
larger.ground.conductor.than.what.is.required.by.the.NEC.for.
proper.steering.of.EMI.from.sensitive.circuits..This.conduc-
tor.must.also.be.insulated.to.avoid.inadvertent.contact.at.
multiple.points.to.ground,.which.could.create.Ground.Loops..
In.many.installations.that.are.having.electronic.control.prob-
lems,.this.essential.wire.is.usually.missing,.is.not.insulated,.
or.improperly.sized..
NEC.size.ratings.are.for.safety.purposes.and.not.necessarily.
for.adequate.relaying.of.noise.(EMI).to.earth.ground.to.avoid.
possible. interference. with. sensitive. equipment.. Therefore.
sizing.this.conductor.1.–.2.sizes.larger.than.required.by.code.
will.provide.better.transfer.of.this.noise..
Johnson.Controls-Frick
®
.requires.that.the.ground.conductor.
meet.the.following::.
•
. Stranded.Copper
•
. Insulated
•
. One.size.larger.than.NEC.requirements.for.conventional.
starters
•
. Two.sizes.larger.than.NEC.requirements.for.VFD.starters
•
. Conduit.must.be.grounded.at.each.end
•
. This. circuit. must. be. complete. from. the. motor. to. the.
starter.continuing.in.a.seamless.manner.back.to.the.plant.
supply.transformer.(power.source)..
For.Direct.Coupled,.Package.Mounted.Starters,.the.ground.
between.the.motor.and.the.starter.may.need.to.be.made.
externally. (Figure. 3).. The. connection. on. the. starter. end.
must. be. on. the. starter. side. of. the. vibration. isolators.. Be.
certain.the.connection.is.metal.to.metal..Paint.may.need.to.
be.removed.to.ensure.a.proper.conductive.circuit..The.use.
of.counter-sunk.star.washers.at.the.point.of.connection.at.
each.end.will.maximize.metal.to.metal.contact.
Figure 15 - motor And Starter grounding
VFD APPLICATIONS
The.primary.ground.conductor.that.accompanies.the.three-
phase.supply.must.be.stranded.copper,.insulated.and.two.
sizes.larger.than.the.minimum.required.by.the.NEC.or.any.
other.applicable.codes..This.is.necessary.due.to.the.increased.
generation.of.EMI.which.is.a.characteristic.of.a.VFD.output.
to.the.motor.when.compared.to.a.conventional.starter..
For.VFD.applications,.isolation.of.the.control.power,.analog.
devices,. and. communications. ground. from. the. 3-phase.
ground.within.the.starter.and.the.electronic.control.panel.may.
be.necessary..This.is.due.to.the.higher.noise.(RFI/EMI).levels.
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.
Содержание Frick 572
Страница 16: ...100 210 IOM FEB 2015 Page 16 VYPER VARIABLE SPEED DRIVE INSTALLATION OPERATION MAINTENANCE Notes ...
Страница 18: ...100 210 IOM FEB 2015 Page 18 VYPER VARIABLE SPEED DRIVE INSTALLATION Figure 7 Vyper Cabinet and Stand ...
Страница 40: ...100 210 IOM FEB 2015 Page 40 VYPER VARIABLE SPEED DRIVE INSTALLATION OPERATION MAINTENANCE Notes ...
Страница 60: ...100 210 IOM FEB 2015 Page 60 VYPER VARIABLE SPEED DRIVE INSTALLATION OPERATION MAINTENANCE Notes ...