Presentation 1 English

7/30/2019 Presentation 1 English

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BASICS OF AN LECTRONICAL


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Electron theory the electrical phenomenon is produced

by a flow of electrons from one area to

another.


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The flow of electrons is caused by

having an excess number in one area,shortage in another

surplus negative

short supply positive

Flow of electrons


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Matter

Anything that takes up space and hasmass: solid, liquid or gas


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Molecule

Smallest portion of matter and retain all

original properties of the original matter,

it is made up of atoms


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Atoms

100 + different types

One molecule of water, is made up of

one atom of oxygen, two atoms of

hydrogen H20


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Atom make up

PROTON - positive charge +

ELECTRON - negative charge -

NEUTRON - no charge (neutral)


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Bound

electronsAre in the inner

orbits, Bound

electrons are verydifficult to remove

from their orbit.

Outer orbits only,

one, two or three

electrons, are easily

knocked out of their

orbit


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Conductors Have 1-3 electrons in outer

orbit, (Free electrons)easily

knocked out of orbit.

Materials such as silver,

copper, aluminum, gold

make good conductors.

4 electronsin outer orbit

Not a good conductor

Not a good insulator

Semi-

Conductors


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Non conductors Insulators, 5 or more electrons

in outer orbit, glass, ceramics,

plastics, rubber, fiber, porcelain,

paper and wood are commonInsulators. Hard to knock the

electrons out of orbit if they have

a strong magnetic pull to the

protons in the nucleus of theatom.


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Current

Movement of free electrons through a

conductor current flow is measured in

amperes(Amps). Must have shortage of

electrons at one end, surplus at other oneelectron does not go the whole distance

moves and bumps others.


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Voltage

Pressure differential causes current to

flow, this pressure is known as voltage

Voltage is a measure in volts with

voltmeter.

(electromotive force, EMF)


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Resistance

n Caused by electrons

bumping into other

atoms, a poor conductor

has greater resistance

than a good conductor.

Poor conductors will

heat up (like a heater).


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Circuits

Must have a power source.A load (something to operate such as a light

bulb or motor)

Wiring for path of electron flow (Conductor) Switch

Circuit protection


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Series circuit, only one

path for current to flow

Series Circuit

Parallel circuit, more than one

path for current to flow, current

flows through all units at once.


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Circuit Problems

Open circuit, Wire is broken

Short to ground, Wire is touching ground

Short to voltage, wire is touching a hotwire. Load device is on even though

switch is off.

High resistance, current is being slowedby corrosion or a poor connection


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Car frame

n Acts as a ground wire, some cars like acorvette have to run ground wiresbecause of fiberglass body

n Ground symbol:


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Ohms law

n Amperes = I - Intensity

n Volts = E - Electromotive force

n Ohms = R - Resistance

n to find E = I x R

I = E / RR = E / I

I X R

E


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Ohms laws For Auto Techs

n Some Auto Techs will use the following

n Amperes = A - Amps

n Volts = V - Volts

n Ohms = R - Resistance

n to find V = A x R

A = V / R

R = V / AA X R

V


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Magnetism

Materials that have this are called Magnets

Some are Natural

Some are made


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Lines of Force

Leave north pole, enter south

Unlike poles attract

Like poles repel

Left hand rule, know which way current

flows, fingers point in direction magnetic

field is moving

Magnetic fields surround any conductor

carrying an electrical current


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Lines of Force


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Solenoid

can be used to push or pull iron core if

off set will be drawn into the middle


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Battery Electro Chemical Device

4 functions1. provides electrical energy to start car.

2. provides electrical energy to ignition system

3. provides electrical energy to accessories whendemands exceed alternators output

4. voltage stabilizer absorbs abnormal voltages

created by electrical components


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Top post Side post


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side and

top post

A side and top post is becoming verycommon today because it will fit so

many cars.


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Battery Construction

Elements consist of two groups of

plates

one more negative than positive plateswith insulated separators in between

usually 9, 11, or 13 plates. 54, 66, or 78

total.case is made of hard rubber (rough

service) or plastic (light service)


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one element in each cell, connected tothe adjoining element, connected in

series, each cell produces about 2.1

volts

case is divided into 6 cells (12.6 volts)

case is divided into 3 cells (6.3 volts)


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Electrolyte

64% water 36% Sulfuric acid

H20-water 64% specific gravity 1.00H2S04-sulfuric acid 36% specific gravity

1.835 - caution

electrolyte 100% specific gravity 1.270


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Charged

positive plate negative plateelectrolyte

H2S04

pb02 pblead peroxide lead


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Discharge

oxygen and hydrogen form water, lead

and sulfate form lead sulfate

pbso4 H20 pbSo4


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Charging send electrons through

opposite way reversing the cycle

Sulfated plates refer to plates hardenwith lead sulfate

Slow long charge to correct sulfated

plates sometimes can't


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Little brown particles floating around

can short out battery (flakes off of the

sulfated plates )

Batteries can freeze if discharged H2O

is water

Charging battery emits oxygen and

hydrogen gas - can explode

To replace add distilled water


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Battery types

WET CHARGE shipped with electrolyte

must charged during storage

DRY CHARGE shipped empty

manufacture gives forming charge dries

the cell elements and seals it. If you

keep moisture out it will remain fully

charged for long time. When neededjust add electrolyte


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Group size

Batteries come in many different groupsizes. A battery's group size simply

determines it's length, width, height, and

terminal configurationWill have a number like group 75,78 or

24 or 24F, 26, 34


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Battery capacity

1) Plate size, the case same size, plates

are different size Larger plates more

amps

2) Number of plates

3) Amount of acid in electrolyte and

battery additives increase the sulfuricacid content of battery


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Battery capacity rating

Cold Cranking Amperes CCA most commonNumber of amperes load of battery will

maintain at 0 degrees Fahrenheit for 30

seconds without battery voltage falling below7.2 volts (1.2 volts per cell)

Size of engine should be smaller than cold

cranking ampere


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Do not be misled by CA thats just

cranking amps. It will give you a higher

reading but it misleads you because it istested at a higher temperature.

Cranking amps are the numbers ofamperes a lead-acid battery at 32

degrees F (0 degrees C) can deliver for

30 seconds and maintain at least 1.2volts per cell (7.2 volts for a 12 volt

battery).


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Recommended Minimum

battery size

4-cylinder 400 CCA

6-cylinder 500 CCA

8-cylinder 575 CCA


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Battery checking visual

Inspection


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Battery checking visual

Inspection

Cracked or leaking case

liquid level, add water use distilled water

preferred (No minerals) or ice meltedout of a freezer

Voltage can discharge across top from

post to postClean battery top and post and cables,

battery hold downs

visual Inspection


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visual Inspection


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Mix baking soda and water to clean

batteries

Clean post and cable with a terminalbrush or post cutter

Coat all connections with grease or use

a spray like NOCO NCP-2 Batterycorrosion spray

Cleaning The Battery


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Battery leakage test

Voltmeter lead at negative post

Voltmeter + lead drag across battery

No voltage should be present anywhere if it

is clean the battery.


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Battery Open Circuit Voltage TestMeasure what the voltage is with the key off

Find out its state of charge. It is a good

starting point, should be at least 12.66 volts

12.66 = fully charged

12.4 = 3/4 charged

12.2 = 1/2 charged

12.0 = 1/4 charged


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Battery Terminals & Bolts

Post or top terminalSide terminal

L terminal used on import

Marine


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Terminal Test

This is the first step.Take a voltmeter

DVOM (Digital volt ohm

meter)Turn to DC Volts

Hook up like picture on

next page.


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Terminal Test

This is just a voltage drop test done onthe battery terminals. You must disable

the ignition and crank over the engine.

Should be under .2 volts.Make sure you do both

terminals Positive &

Negative


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Battery Drain test

Battery Drain Key off

Hook up a ammeter in series reading

should not exceed the following77 older cars .01 amps, 10 ma (milliamps)

78-85 .02 amps-.025 amps, 20-25 ma

1986 & newer .05 amps, 50 ma


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Testing specific gravity

Hydrometer check before adding water

fully charged battery should read 1.270

should not vary more than 50 pointsbetween cells if it does recharge and

check again

Maintenance free batteries are sealed,cannot get into some. No way to add

water or check specific gravity.


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Charging batteries

Clean up first

Unhook cables - check liquid level

Don't charge over 16 volts if plates aresulfated or if battery has been

discharged for some time

Slow charge for a long period 24 hoursdon't allow temperature to exceed 100

Never fast charge batteries


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Most batteries in cars are 12 volt with

negative ground.

6 volt older cars and 18 wheelers may

have positive ground


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SAFETY: do not allowbattery acid to contact eyes

skin or fabrics if you do flushwith lots of water, and get

teacher or medical help flush

eyes for 15 minutes


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Jump starting cars

positive to positive

negative to negative

Hook up negative cable last on car withdead battery on a good ground. Not on

the battery. If sparks occur no

Hydrogen to blow up

b tt d t t


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battery date tags


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Did You Know Batteries Lose Power

While Sitting on the Shelf?

A battery can permanently lose some of its capacity when it's

stored in a partly or fully discharged state. Periodic charging

during storage can minimize the deterioration, but not all

battery distributors and dealers do the necessary charging.That's why you may want to know how to read the date codes,

which show when the product was manufactured, on a new

product, to help you make sure you're really buying a fresh

battery.

So, how do you read a date code?


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Most Brands of Batteries

JOHNSON CONTROLS, INC. - INTERSTATE BATTERIES,

Motorcraft, East penn - Deka, GNB -Champion, Stowaway:

The letters and numbers are on a sticker affixed to the battery or hot-stamped

into the case cover along the top edges of the battery. The ship date codes

begin with a letter: A stands for January, B for February and so on (some

shipping codes skip the letter I, so it cannot be confused with the number 1.

In those cases, J would represent September, K - October, L - November and

M - December). The next digit is a number which represents the year the

battery was shipped. Therefore, an A6 would mean the battery was shipped in

January of 1996.


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Exceptions DELCO - Freedom, Voyager, and some Sears brands:

The code dates are stamped on the cover, usually near the posts.

The first character represents the year (0-9) and the second shows

the month (A-M, skipping I). For example, 4CN1 would stand for

1994, March.

EXIDE - Napa Legend, Edge, Power-Tron and Titan:

The fourth or fifth character may be a letter code for the

month and the following character a number code for

the year (i.e. RO8F3B stands for June 1993)

Last 3 pages 2000 Interstate Battery System of America, Inc.


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Always Disconnect the ground cable

first. (Negative Cable on cars)

Always hook up the ground cable last

If you disconnect the positive first

and touch ground you will havesparks.

Removing Batteries


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Hooking batteries in series

Voltage goes up


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Hooking batteries in parallel

Voltage stays the sameamperage goes up


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Generator

Electromagnetic device, produces

electricity to run accessories and charge

battery


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If wire is passed through magnetic field

voltage is generated

If passed in the opposite directioncurrent flow reversed


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To increase volts and amps

1. increase strength of magnetic field

2. increase the speed wire moves

through the magnetic field


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Basic AC operation current

flows positive, negative


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Basic DC operation

Current flows one way,

accomplished by split ring


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Charging Indicators

ammeter

indicator light

VoltageMonitor


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Alternator


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Alternators

More efficient at lower speeds

Lighter - aluminum construction

Requires only 2 or 3 amps passingthrough slip rings compared to high

amperage in D.C. generator

Governs its own maximum currentoutput


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Alternator

Generators - moving conductor throughstationary field to induce voltage

Alternator - a permanent magnet is rotatedinside a stationary conductor

maximum voltage occurs when conductor

cuts heaviest lines of force


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Parts of a Alternator


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