bex – basic electricity – unit 13
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BEX – Basic Electricity – Unit 13. Magnetic Motors REF: Delmar’s Standard Textbook of Electricity , Unit 13. Magnetic Motors. Lesson Objectives: To understand the principles of magnetism as it applies to magnetic motors To identify the different types of motors - PowerPoint PPT PresentationTRANSCRIPT
BEX – Basic Electricity – Unit 13
Magnetic MotorsREF: Delmar’s Standard Textbook of Electricity, Unit 13
Magnetic Motors
Lesson Objectives:To understand the principles of magnetism as it applies to magnetic motorsTo identify the different types of motorsTo identify the various components of an electromagnetic motor
Magnetic MotorsMagnetic properties
Unlike poles attractLike poles repelThe basis for the operation for a motor
Magnetic MotorsMagnetic properties
Current flow through a conductor creates a weak magnetic fieldWrapping a conductor increases the magnetic field
Magnetic Motors
Magnetic PropertiesWhen a current carrying conductor is placed inside of a magnetic field, the conductor moves towards the weaker magnetic field on the outside of the magnet
Magnetic Motors
Components
Magnetic MotorsA Simple Electromagnetic Motor
Armature windingsField windingsPole shoesBrushesCommutatorPower source
Magnetic Motors
Field Coils & Pole Shoes:Heavy copper wire wrapped in a coilSurrounding an iron coreForms an electromagnet
Magnetic Motors
The Armature:Rotates within stationary field coilsConsists of heavy loops of insulated copper wireWraps around (and insulated from) a laminated iron core
Magnetic Motors
The Commutator:A series of split ring copper segment barsForms a sliding contact area for brushes
Magnetic Motors
The Brushes:Made of a mixture of carbon and copperUsed to conduct high amperage through armature windings
Magnetic Motors
Conductor/Field Coil Interaction:Magnetic fields react by moving the conductor towards the weaker magnetic fieldArmature rotates energizing the next contact on the commutator
Magnetic Motors
Counter Electromotive Force (CEMF):Produced by electromagnetic induction in the windingsTends to act against the supply voltageIncreases with motor speedReduces current/torque of motor
Magnetic Motors
Types of motors
Magnetic MotorsSeries Wound:Current flows through the field windingsThen through the armature windingsReturns to groundMaximum torque is developed during initial start upCEMF increases with motor speed
Magnetic Motors
Parallel Wound:Current flows in parallel to the field windings, positive brushes and commutator, armature, and grounding brushesA low torque motorSpins at lower speedsCEMF does not increase with motor speed
Magnetic MotorsCompound Wound:Most of the field coils are in series to the armatureOne field coil is connected to groundCombines the best properties of the series and the parallel wound motorsMotor has good initial torque and speed
Magnetic MotorsPermanent Magnet Motor:Electromagnetic field coils are replaced with permanent magnetsReduces the size and weight of motorUses less current
REVIEW…..
HOW DOES A MOTOR USE MAGNETISM?HOW IS ELECTRICAL ENERGY CONVERTED INTO MECHANICAL ENERGY?
WHAT IS THE MOVEABLE, INTERNAL FIELD CALLED?WHAT IS THE STATIONARY OUTSIDE FIELD CALLED?NAME THREE WAYS OF CONNECTING THE 2 FIELDS ELECTRICALLY.
REVIEW….
WHAT IS COUNTER ELECTROMOTIVE FORCE?HOW DOES THE INTERNAL FIELD GETS IT’S POWER AND GROUND?HOW IS A TYPICAL STARTER MOTOR GROUNDED?
HOW IS A PERMANENT MAGNET STARTER DIFFERENT FROM ELECTROMAGNET STARTER?WHAT EFFECT DO THE POLE SHOES HAVE?
Elizabethtown Technical CollegeElizabethtown Technical CollegeBasic Electricity BEXS100/101Basic Electricity BEXS100/101Text: Text: Delmar’s Standard Textbook of ElectricityDelmar’s Standard Textbook of ElectricityMagnetic MotorsMagnetic Motors