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by Russell Krick

Publisher

The Goodheart-Willcox Co., Inc. Tinley Park, Illinois Š Goodheart-Willcox Co., Inc.


Š Goodheart-Willcox Co., Inc.


Magnetic Field Action  Made up of invisible lines of force  Since like charges (fields) repel each other and unlike charges (fields) attract each other, magnetic fields can produce motion

© Goodheart-Willcox Co., Inc.


Magnetism and Induction Electromagnets The strength of an electromagnetic coil is affected by The amount of current The # of windings The size, length, and type of core The direction and angle that the lines of force are cut

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Magnetic Field Action

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Simple Electric Motor If a current-carrying winding is placed inside a magnetic field, the winding rotates away from the pole shoes

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Commutator and Brushes Commutator reverses the electrical connection when the loop rotates around

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Armature and Field Windings

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Starter Motor  The starter motor has a drive assembly that engages the ring gear and rotates the engine.  A – Starter Drive  B – Flywheel Ring Gear  C – Pinion Gear

9 © Goodheart-Willcox Co., Inc.


Starter Motor

 The pinion gear meshes with the ring gear before the motor turns  The teeth on the pinion gear are tapered to ensure smooth engagement  The drive assembly includes an overrunning clutch. 10 © Goodheart-Willcox Co., Inc.


Starter Solenoid Plunger movement pulls the disc into contact with two battery terminals to activate the starter

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Movable Pole Shoe Starting Motor Uses a yoke lever to move the pinion gear into contact with the flywheel

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Starter-Mounted Solenoid Solenoid plunger moves a shift lever to engage the pinion gear

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Starter-Mounted Solenoid Solenoid completes the battery-to-starter circuit

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Reduction Starter Extra gears further increase torque

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Neutral Safety Switch Wired in series with the starter solenoid

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Starting System Circuit

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Starting System Service

 Voltage drop test

 Where do I connect the meter to do a voltage drop test of this terminal?

18 © Goodheart-Willcox Co., Inc.


Starting System Service  Voltage drop test  Where do I connect the meter to do a voltage drop test of the positive starter cable?

19 © Goodheart-Willcox Co., Inc.


Starting System Service  Voltage test  Where do I connect the meter to check for voltage to the “S” terminal while cranking?

20 © Goodheart-Willcox Co., Inc.


Starting System Service

 Shimming Starter Motors

 Pry gear into engaged position, then check clearance with wire gauge.

21 © Goodheart-Willcox Co., Inc.


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 Recharges battery after cranking  Supplies the car’s electricity when the engine is running  Provides output voltage slightly higher than battery voltage  Changes output to meet varying loads © Goodheart-Willcox Co., Inc.


 Two types:  AC Generator (alternator)  DC Generator

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Generator versus Alternator

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Alternator Operation

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Generator Operation  Generator Operation  Voltage is induced when a magnetic field moves across a conductor  A bar magnet, with its magnetic field, rotates inside a conductive loop of wire  The rotating magnet is the rotor, and the stationary conductor is 27 the stator © Goodheart-Willcox Co., Inc.


Generator Operation  Electromagnets • The strength of an electromagnetic field is affected by  The amount of current  The # of windings  The size, length, and type of core  The direction and angle that the lines of force are cut © Goodheart-Willcox Co., Inc.

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Generator Operation

 Rotor

 Rotating electromagnet  Regulate the power output of the generator by increasing or decreasing the strength of the electromagnetic field 29

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Generator Operation 11Phase Phase

33Phases Phases

30 © Goodheart-Willcox Co., Inc.

 Stator  3 windings to create 3 phase power

22Phases Phases


AC Output  Alternating current flows one way, then the other  As the rotor turns into one stator winding, current is induced  When the same rotor pole moves into the other stator winding, current reverses direction

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Rectified AC Current  Automobile’s electrical system requires direct current (DC) which flows one way  Alternator output must be rectified (changed) from AC to DC  Diode allows current flow in only one direction  Several are connected into a rectifier bridge © Goodheart-Willcox Co., Inc.


Diode Acts as a one way electrical check valve

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Diode Operation

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Generator Components This rectifier uses 2 heat sinks to support 3 diodes each for a total of six diodes.  3 Positive diodes.  3 Negative diodes.  One side of diode attaches to the heat sink.  Other side of diode attaches to the straps in the center. 35 © Goodheart-Willcox Co., Inc.


Generator Components  Rectifier  At least 6 diodes  Changes AC to DC  Some Generators may have Capacitors to help smooth current. 36 © Goodheart-Willcox Co., Inc.


 Stator

Generator Components

 Insulated with varnish  3 separate windings  Arranged in specific order  Highly permeable laminations concentrate lines of flux

37 © Goodheart-Willcox Co., Inc.


Rotor Operation As the rotor spins, alternating polarity produces alternating current

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Brushes and Slip Rings

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Stator and Rectifier Rectifier consists of six diodes, connected to the stator windings

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Alternator Fan  Mounted on the front of the rotor shaft  Draws air through and over the alternator  Cools the windings and diodes

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Pulley and Belt Crankshaft turns the alternator belt

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Voltage Regulator  Controls alternator output voltage  Changes the amount of current flowing through the rotor windings  Engine control module (ECM or PCM) can serve as the voltage regulator

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Internally Regulated Alternator

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Generator Components  Voltage Regulator  3 Types:  Internally mounted  Externally mounted  Remote mounted

 Controls current sent through the rotor 45 © Goodheart-Willcox Co., Inc.


Voltage Regulators

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Voltmeter Indicator  Battery has 12.6 volts when fully charged  Alternator output must be higher:  13–15 volts

 Voltmeter shows voltage

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External Components  Indicator Lamp  Alerts the driver  Many shapes, may say “Batt”, “Charge”, or be a symbol as shown  On/Off, does not indicate amount of performance. 48 © Goodheart-Willcox Co., Inc.


External Components  Voltmeter  Indicates to the driver the level of performance of the system  Safer than Ammeters

49 © Goodheart-Willcox Co., Inc.


31 Starting Charging systems II