Ac motors.pdf

Table of Contents

Introduction...............................................................................2 AC.Motors.................................................................................4 Force.and.Motion......................................................................6 AC.Motor.Construction............................................................ 2Magnetism.............................................................................. 7 Electromagnetism................................................................... 9 Developing.a.Rotating.Magnetic.Field.....................................24 . Rotor.Rotation.........................................................................29 . Motor.Specifications...............................................................34 . NEMA.Motor.Characteristics. .................................................37 Derating.Factors......................................................................43 . AC.Motors.and.AC.Drives. ......................................................45 Matching.Motors.to.the.Load..................................................49Motor.Enclosures....................................................................53 Mounting.................................................................................56 . Siemens.AC.Induction.Motors. ...............................................6 Review.Answers......................................................................70 Final.Exam............................................................................... 7quickSTEP.Online.Courses...................................................... 76



Introduction

Welcome.to.another.course.in.the.STEP.series,.Siemens. Technical.Education.Program,.designed.to.prepare.our. distributors.to.sell.Siemens.Energy.&.Automation.products. more.effectively..This.course.covers.Basics of AC Motors.and. related.products.. Upon.completion.of.Basics of ACMotors.you.should.be.able. to:

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Explain.the.concepts.of.force,.inertia,.speed,.and.torque Explain.the.difference.between.work.and.power Describe.the.construction.of.a.squirrel.cage.AC.motor Describe.the.operation.of.a.rotating.magnetic.field Calculate.synchronous.speed,.slip,.and.rotor.speed Plot.starting.torque,.accelerating.torque,.breakdown.torque,.and.full-load.torque.on.a.NEMA.torque.curve Apply.derating.factors.as.required.by.an.application Describe.the.relationship.between.V/Hz,.torque,.and. horsepower Match.an.AC.motor.to.an.application.and.its.load Identify.NEMA.enclosures.and.mounting.configurations Describe.Siemens.NEMA.and.IEC.motors Describe.torque.characteristics.and.enclosures.of.Siemens. above.NEMA.motors

2This.knowledge.will.help.you.better.understand.customer. applications..In.addition,.you.will.be.better.able.to.describe. products.to.customers.and.determine.important.differences. between.products..You.should.complete.Basics of Electricity before.attempting.Basics of AC Motors..An.understanding.of. many.of.the.concepts.covered.in.Basics.of.Electricity.is.required. for.Basic.of.AC.Motors..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. Siemens.is.a.trademark.of.Siemens.AG..Product.names. mentioned.may.be.trademarks.or.registered.trademarks.of.their. respective.companies..Specifications.subject.to.change.without.notice. National.Electrical.Code®.and.NEC®.are.registered.trademarks. of.the.National.Fire.Protection.Association,.Quincy,.MA.0269747.. NEMA®.is.a.registered.trademark.and.service.mark.of.the. National.Electrical.Manufacturers.Association,.Rosslyn,.VA. 22209. Underwriters.Laboratories.Inc.®.and.UL®.are.registered. trademarks.of.Underwriters.Laboratories.Inc.,.Northbrook,.IL. 60062-2096....