electricity.pdf

Table of Contents

Introduction...............................................................................2

Electron.Theory..........................................................................4

Conductors,.Insulators.and.Semiconductors.............................5

Electric.Charges........................................................................7

Current......................................................................................9

Voltage....................................................................................

Resistance............................................................................... 3

Simple.Electric.Circuit............................................................. 5

Ohm’s.Law.............................................................................. 6

DC.Series.Circuit..................................................................... 8

DC.Parallel.Circuit....................................................................23

Series-Parallel.Circuits.............................................................30

Power......................................................................................34

Magnetism..............................................................................37

Electromagnetism...................................................................39

Introduction.to.AC...................................................................42

AC.Generators.........................................................................44

Frequency................................................................................47

Voltage.and.Current.................................................................48

Inductance...............................................................................5

Capacitance.............................................................................56

Inductive.and.Capacitive.Reactance........................................6

Series.R-L-C.Circuit..................................................................67

Parallel.R-L-C.Circuit.................................................................69

Power.and.Power.Factor.in.an.AC.Circuit................................ 7

Transformers...........................................................................75

Three-Phase.Transformers.......................................................80

Review.Answers.....................................................................83

Final.Exam...............................................................................84

quickSTEP.Online.Courses......................................................88

Introduction

Welcome.to.the.first.course.in.the.STEP.series,.

S iemens. T echnical. E ducation. P rogram.designed.to.prepare.

our.distributors.to.sell.Siemens.Energy.&.Automation.products.

more.effectively..This.course.covers.Basics.of.Electricity.and.is.

designed.to.prepare.you.for.subsequent.courses.on.Siemens.

Energy.&.Automation.products.

Upon.completion.of.Basics.of.Electricity.you.will.be.able.to:

•. Explain.the.difference.between.conductors.and.insulators

•. Use.Ohm’s.Law.to.calculate.current,.voltage,.and.

resistance

•. Calculate.equivalent.resistance.for.series,.parallel,.or.

series-parallel.circuits

•. Calculate.voltage.drop.across.a.resistor

•. Calculate.power.given.other.basic.values

•. Identify.factors.that.determine.the.strength.and.polarity.of.

a.current-carrying.coil’s.magnetic.field

•. Determine.peak,.instantaneous,.and.effective.values.of.an.

AC.sine.wave

•. Identify.factors.that.effect.inductive.reactance.and.

capacitive.reactance.in.an.AC.circuit

•. Calculate.total.impedance.of.an.AC.circuit

•. Explain.the.difference.between.real.power.and.apparent.

power.in.an.AC.circuit

•. Calculate.primary.and.secondary.voltages.of.single-phase.

and.three-phase.transformers

•. Calculate.kVA.of.a.transformer

The.objectives.listed.above.may.sound.strange.to.you..You.may.

also.wonder.why.you.would.need.to.know.these.things.to.sell.

Siemens.Energy.&.Automation.products..Developing.a.basic.

knowledge.of.electrical.concepts,.however,.will.help.you.to.

better.understand.customer.applications..In.addition,.you.will.be.

better.able.to.describe.products.to.customers.and.determine.

important.differences.between.products.

If.you.are.an.employee.of.a.Siemens.Energy.&.Automation.

authorized.distributor,.fill.out.the.final.exam.tear-out.card.and.

mail.in.the.card..We.will.mail.you.a.certificate.of.completion.if.

you.score.a.passing.grade..Good.luck.with.your.efforts.

Electron Theory

Elements of an Atom .

All.matter.is.composed.of.molecules.which.are.made.up.of.a.

combination.of. atoms ..Atoms.have.a.nucleus.with.electrons.

orbiting.around.it..The.nucleus.is.composed.of.protons.and.

neutrons.(not.shown)..Most.atoms.have.an.equal.number.of.

electrons.and.protons.. Electrons .have.a.negative.charge.(-)..

Protons .have.a.positive.charge.(+).. Neutrons .are.neutral..The.

negative.charge.of.the.electrons.is.balanced.by.the.positive.

charge.of.the.protons..Electrons.are.bound.in.their.orbit.by.

the.attraction.of.the.protons..These.are.referred.to.as.bound.

electrons.

Electron

Proton

Nucleus

Free Electrons .

Electrons.in.the.outer.band.can.become.free.of.their.orbit.

by.the.application.of.some.external.force.such.as.movement.

through.a.magnetic.field,.friction,.or.chemical.action..These.

are.referred.to.as. free electrons ..A.free.electron.leaves.a.void.

which.can.be.filled.by.an.electron.forced.out.of.orbit.from.

another.atom..As.free.electrons.move.from.one.atom.to.the.

next.an.electron.flow.is.produced..This.is.the.basis.of.electricity.

Conductors, Insulators and Semiconductors

Conductors .

An. electric current .is.produced.when.free.electrons.move.

from.one.atom.to.the.next..Materials.that.permit.many.

electrons.to.move.freely.are.called.conductors..Copper,.

silver,.aluminum,.zinc,.brass,.and.iron.are.considered.good.

conductors ..Copper.is.the.most.common.material.used.for.

conductors.and.is.relatively.inexpensive..

Insulators .

Materials.that.allow.few.free.electrons.are.called. insulators ..

Materials.such.as.plastic,.rubber,.glass,.mica,.and.ceramic.are.

good.insulators.

An.electric.cable.is.one.example.of.how.conductors.and.

insulators.are.used..Electrons.flow.along.a.copper.conductor.to.

provide.energy.to.an.electric.device.such.as.a.radio,.lamp,.or.a.

motor..An.insulator.around.the.outside.of.the.copper.conductor.

is.provided.to.keep.electrons.in.the.conductor.

Rubber Insulator

Copper Conductor

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