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Starting System Principles

Uses battery power

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AUTOMOTIVE STARTING SYSTEMS

Starter Circuit Electric DC Motor

(starter motor) Solenoid or Relay Gear Drive Switches

& Controls Wiring Testing Removing Starter

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STARTING SYSTEM PARTS Battery Ignition switch Solenoid Starting motor

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STARTER CIRCUIT

Battery / Cables Magnetic

Switches Solenoids

• Pull in Windings

• Hold in Windings

• Pinion Gear

Starter Relay

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Starter Circuit Simplified

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Starter Solenoid Functions * Close battery to

starter connection * Push pinion gear

into fly wheel * Bypass the

resistance wire of ignition circuit

Move the starter drive into mesh w. flywheel

Complete the starter circuit

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Starting System Action

Energizes solenoid

Current flows to Solenoid

Turn key

Connects current to starter motor

Motor turns flywheel Turns crankshaft

Moves pistons up and down

1

Turns starter

Moves pinion forward

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Starter System Action cont.

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Starter Motor Fundamentals

Converts Electrical Energy From Battery Into

Mechanical Energy

TORQUE

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DC MOTOR Basic Components

Housings and End Frames

Pole Shoes (magnets)

Field Coils • (windings) x 3 or 4

Armature (spins) Commutator Brushes x4

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MOTOR OPERATION

Magnetic Field Action• made of invisible lines of force (flux)

• flow through wire

• flow around wire

• alike charges repel

• Dissimilar Charges attract(spinning action)

• Used to produce motion

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DRIVE MECHANISM

Positive engagement• Movable pole shoe

Solenoid-actuated• Gear reduction drive

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Simple Electric Motors

Wire loop field Set up between

poles POLE SHOES

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Changing Electricity Into Motion

Place windings inside pole shoes Current through loop Fields act upon each other

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Commutators and Brushes

Used to keep motor spinning• by controlling current passing through windings

commutator Sliding electrical connection

• Between motor windings and brushes

• Many segments

• Insulated from each other Motor brushes

• Ride on comutator

• (slide on commutator)

• Carry current to spinning windings

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Commutators and Brushes

Increasing Motor Power• several windings

• wires

Commutator • several segments

• constant smooth motion

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Armatures

Must produce HIGH torque• turning power

• relatively high speed

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Starter Armature parts shaft supports windings/armature inside housing Core (holds windings in place)

• made of iron (Fe) increases magnetic field strength Commutator

• for brush contact• Windings

• wires

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Field Windings stationary insulated wires wrapped in circular shape creates strong magnetic field around motor armature 5-10 x stronger than perminate magnets field in pole shoes acts against field in

armature = motor spins

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Pinion gear mechanism

Pinion gear Clutch Housing

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Starter Pinion Gears

Small gear on armature shaft Engages to flywheel Meshes

Fly Wheel Turns Engine

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Overrunning Clutch

Locks pinion gear in one direction Releases it in other direction Spiral grooves in shaft Allows starter motor to crank the

engine Protects the starter from damage if the

starter is cranked while the engine is running

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Starter Solenoid

High current relay Makes electrical connection between

• Battery & starter

Electromagnetic switch Handle VERY HIGH currents

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Starter Solenoid Operation

Key turned (start position) Current flows through solenoids windings Produces magnetic field Pulls plunger and disc into coil windings Causes disc to touch both high current

terminals Completes circuit battery to starter Current of 150-200A

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Solenoid

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Key Released

Current disconnected Magnetic field collapses Plunger slides back Starter shuts off

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Increasing Motor Power

Several windings Wires Comutator Several segments Constant smooth motion

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RELATED MOTOR TERMINOLOGY

Left hand or right hand rule Torque Current Draw

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STARTER DRIVE END Connects the armature

shaft to the flywheel. Usually shifted out by the

solenoid. Contains an over- running

clutch for protection. Pinion gear meshes with

the flywheel ring gear. Returned to the rest

position by a spring.

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SOLENOID

A linear motor Contains two windings a

pull-in and a hold-in winding.

Pushes the starter drive(pinion) into mesh with the flywheel ring gear.

Completes the circuit to the motor.

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CONTROL CIRCUIT

Starting Safety Switch

Neutral Safety Switch• On

transmission

• On Clutch

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Starting Motor Types

classified by: kind of pinion gear engagement moveable pole shoe solenoid Movable pole shoe uses a yoke “Y” moves pinion gear hinged shoe on starter

frame yoke links pole shoe & pinion gear

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Internal Motor Circuits

3 common internal connections

Series• maximum torque

• torque decreases throughout cranking

Shunt• Less torque

• More constant torque

Compound• series/shunt

• good toque

• constant speed

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Neutral Safety Switch

prevents cranking unless in P or N Ford - brake on LOCATION Connected in series with the ignition

switch and solenoid• shifter or transmission

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Starter Relay Uses small current to

control • a

LARGER current

• Computer controls circuit (mV)

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Starter Types

Starter Mounted Solenoids plunger moves shift lever

• GM/Chrysler

Permanent Magnet Starter Use high strength permanent magnets NOT CONVENTIONAL WINDINGS = MORE torque

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Starter Motor Torque

Must turn engine all components Can Not Stall Reduction starter

• extra set of gears

• increase rotating force

• higher speeds

• higher torque

• more constant cranking speeds

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STARTER TESTING

Preliminary Tests Safety Precautions Troubleshooting

Procedures Battery Load Test Cranking Voltage Test Cranking Current Test Insulated Resistance

Test

Starter Relay By-pass Test

Ground Circuit Resistance Test

Voltage Drop to Control Unit

Test Components

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Problems

Starter relay or solenoid clicks• low battery charge

Whining• Plunger stuck

Grinding• Poor engagement

Slow turn• Low battery

• Internal short

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Battery Load Test

VAT 40 All Accessories on ½ CCA

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Test

Cranking Voltage • DVOM across battery

Cranking Current Test• Inductive Pick Up

• Current draw

• 150-200 AMPS

Voltage Drop Test

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Tests Test Relay Ground Circuit

Resistance Test Starter Relay Bypass

Test Ground test Bench test

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Starter Motor Disassembly