Tti basic electricity level 1

Introduction to Electricity – Level I
Basic Electricity

ELECTRICAL
The aim of this course is to introduce and familiarise trainees with the basics of Basic Electricity as a
foundation for understanding theoretical and practical electronics.
We recommend that you participate continually in the Training Programmes offered by TTi in order to keep
your theoretical and practical knowledge of each vehicle up-to-date and to broaden it.

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Contents
ELECTRICAL.................................................................................................................................................2
Contents.........................................................................................................................................................3
INTRODUCTION TO ELECTRICITY.............................................................................................................5
DEFINITION OF SEVERAL TERMS .........................................................................................................5
ELECTRICAL CHARGE ................................................................................................................................6
ELECTRICAL MAGNITUDES........................................................................................................................7
DIFFERENCE IN POTENTIAL ......................................................................................................................7
UNIT OF MEASUREMENT OF ELECTRICAL VOLTAGE .......................................................................8
ELECTRICAL CURRENT..............................................................................................................................9
UNIT OF MEASUREMENT OF CURRENT ..............................................................................................9
DIRECT CURRENT AND CONSTANT VOLTAGE...................................................................................9
ALTERNATING CURRENT AND VOLTAGE ..........................................................................................10
SYMBOLS................................................................................................................................................11
ELECTRICAL RESISTANCE.......................................................................................................................12
UNIT OF MEASUREMENT OF ELECTRICAL RESISTANCE ...............................................................12
ELECTRICAL RESISTANCY.......................................................................................................................13
INFLUENCE OF TEMPERATURE ON RESISTANCE ...........................................................................13
CIRCUIT PROTECTION..............................................................................................................................14
Concept of the short-circuit......................................................................................................................14
APPLICATION OF OHM'S LAW..............................................................................................................15
OHM'S SECOND LAW ............................................................................................................................15
SERIES AND PARALLEL CIRCUITS .....................................................................................................16
SERIES CIRCUIT ....................................................................................................................................16
PARALLEL CIRCUIT ...............................................................................................................................16
CONCEPTS OF MAGNETISM AND ELECTROMAGNETISM...................................................................16
MAGNETS ...............................................................................................................................................17
MAGNETIC FIELD...................................................................................................................................17
ELECTRO-MAGNETISM.........................................................................................................................18
COIL AND MAGNETIC FIELD.................................................................................................................18
DID YOU KNOW THAT: ..........................................................................................................................18
ELECTROMAGNET APPLICATION: RELAYS .......................................................................................19
MEASURING INSTRUMENT ......................................................................................................................20
ELECTRONIC MULTIMETER .....................................................................................................................21
MEASUREMENT USING A MULTIMETER ............................................................................................21
BATTERY.................................................................................................................................................21
APPLICATION SPECIFICATIONS..........................................................................................................22
APPLICATION AS A FUNCTION OF REGIME FOR USE .....................................................................22

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BATTERY CONSTRUCTION ..................................................................................................................22
COMPOSITIONS AND CHEMICAL REACTIONS ..................................................................................24
ACTIVE MASS.........................................................................................................................................25
SPACER...................................................................................................................................................25
CONNECTION OF THE PLATES ...........................................................................................................25
CHARGE INDICATOR.............................................................................................................................25
SAFETY INFORMATION.........................................................................................................................26
STORAGE................................................................................................................................................27
RECHARGING YOUR BATTERIES........................................................................................................27
CURRENT DRAIN TEST.........................................................................................................................28
BASIC STRUCTURE OF THE ALTERNATOR.......................................................................................28
ALTERNATORS WITH CLAW-POLE TYPE ROTOR AND SLIP RINGS ..............................................29
VOLTAGE REGULATOR ........................................................................................................................30
..................................................................................................................................................................30
ELECTRONIC REGULATORS................................................................................................................30
Z DIODE (ZENER DIODE) ......................................................................................................................30
ADJUSTMENT OF TRANSISTORISED VOLTAGE ...............................................................................31
ELIMINATION OF FAULTS .....................................................................................................................32
STARTER MOTOR..................................................................................................................................33
ELECTRIC STARTER MOTOR...............................................................................................................33
SOLENOID...............................................................................................................................................34
COUPLING SYSTEM ..............................................................................................................................35
GEAR WHEEL.........................................................................................................................................35
GEAR MECHANISM................................................................................................................................35
FREE-RUNNING GEAR ..........................................................................................................................35
ROLLER FREE-RUNNING GEAR ..........................................................................................................36
ELIMINATION OF FAULTS .....................................................................................................................36
EXERCISES.............................................................................................................................................37

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INTRODUCTION TOELECTRICITY
DEFINITION OF SEVERAL TERMS
Matter - The study of matter and its composition is essential for understanding electronic theory. Matter, in
simple terms, is everything in solid, liquid or gaseous form, which has mass and occupies space. Matter
may also be referred to as body.
Events - The things with which we have contact and which do not occupy space, are referred to in this
manner and are not considered to be matter. Examples of events are sound, heat and electricity. If we
divide matter down to its smallest component part, we end up with the molecule.
Molecule - retains the characteristic of the original matter. If we divide this part of matter further, we end up
with the atom.
Atom - Elements composed of other particles, and which when combined form various substances.
Atomic particles are referred to as:
Electrons: Elements with a negative charge which circulate freely orbiting the nucleus of the atom, also
referred to as electrosphere.
Protons: Have a positive charge and are concentrated to comprise the nucleus of the atoms.
Neutrons: Have no charge, but comprise part of the atom nucleus.

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An atom has three classifications according to the number of electrons and protons.
These are:
Neutron:Has the same number
of protons and electrons.
Positively-charged atom or
Cation: Has less electrons than
protons.
Atom with negative charge or
Anion: Has more electrons than
protons.
ELECTRICAL CHARGE
As some atoms are forced to yield electrons and others to receive electrons, it is possible to transfer
electrons from one body to another.
When this occurs, there must be an equal distribution of positive and negative charges in each atom.
Therefore, a body shall contain excess electrons and its charge shall have a negative (-) polarity.
The other body, in turn, shall contain an excess of protons and its charge shall have a positive (+) polarity.
When a pair of bodies have the same charge, that is, both positive (+) or both negative (-), they are said to
have equal charge.
When a pair of bodies have different charges, i.e.: one body is positive (+) and the other is negative (-),
they are said to have unequal or opposite charges.
The level of electrical charge that a body has is defined by the difference between the number of protons
and the number of electrons contained in the body.

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ELECTRICAL MAGNITUDES
Electricity is part of our everyday life, whether in the form of lightning or the simple act of switching on a
light. Electrical charges flow around us, producing light, sound and heat. In order to understand how such
effects are obtained, it is essential first of all to understand the movement of electrical charges and their
specifics.
The units of measurement of magnitudes are named after the people who discovered them:
Unit Magnitude Origin of Name Profession
Volt Voltage Alessandro Volta Italian physicist
Watt Output James Watt Scottish mathematician
Ampere Current André Marie Ampère French mathematician
Ohm Resistance Georg Somon Ohm German physicist
DIFFERENCE IN POTENTIAL
When the work carried out by two energised bodies is compared, it is automatically their electrical potential
that is being compared. The difference between the work directly defines the difference in electrical
potential between the two bodies.
The difference in potential exists between bodies energised with different charges or with the same type of
charge.
The difference in electrical potential between two energised bodies is also referred to as electrical voltage.
The symbol used to represent the intensity of the electrical voltage is the letter U.

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UNIT OF MEASUREMENT OF ELECTRICAL VOLTAGE
The voltage (or potential difference) across two points can be measured using instruments. The unit of
measurement of voltage is the volt, which is represented by the symbol V.
As with any other unit of measurement, the unit of measurement of voltage (volt) also has multiples and
sub-multiples to suit any situation. Refer to the table below:
DESIGNATION SYMBOL NAME AND VALUE
Multiples
Megavolt MV 1MV or 1,000,000 V
Kilovolt kV 1 kV or 1000 V
Units Volt V _
Sub-multiples
Millivolt mV 1 mV or 0.001 V
Microvolt uV 1 µV or 0.000001 V
For electricity, the volt and the kilovolt are used most frequently as units of measurement, whereas in
electronics the units of measurement used most frequently are the volt, the millivolt and the microvolt.

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ELECTRICAL CURRENT
Electrical current consists in the directed movement of charges, caused by electrical imbalance (difference
in electrical potential) between two points.
In order for there to be electrical current, there must be a difference in electrical potential and the circuit
must be closed.
Then, we can say that there is voltage without current, but there can never be current without voltage.
This is because voltage directs electrical charge.
The symbol used to represent the intensity of the electrical current is the letter I.
UNIT OF MEASUREMENT OF CURRENT
Current is an electrical magnitude which, like all magnitudes, can have its intensity measured using
instruments. The unit of measurement of the intensity of current is the Ampere, which is represented by the
symbol A.
As with any other unit of measurement, the unit of measurement of current has multiples and sub-multiples
to suit any situation as shown in the table below:
Multiples Kiloampere kA 1 kA or 1000 A
Units Ampere A _
Sub-multiples
Milliamp mA 1 mA or 0.001 A
Microamp µA 1 µA or 0.000001 A
Nanoamp nA 1 nA or 0.000000001 A
In the field of electronics, the terms ampere (A), milliampere (mA) and microampere (µA) are used more
often.
DIRECT CURRENT AND CONSTANT VOLTAGE
If the voltage remains constant, there will be a current which will always flow in the same direction, which is
known as direct current. This voltage that generates a direct current is known as constant voltage. Direct
current is abbreviated to DC, the abbreviation used to indicate constant voltage and DC voltage.

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Power cells and accumulator batteries supply direct
current. Certain types of electrical generators are used
to supply constant voltage The terminals of a constant
voltage source are marked with "+" (positive) and "-"
(negative) markings indicating the direction in which the
circuit current flows.
In the conventional direction current flows from the "+"
terminal via the "-" terminal and in real or electronic
terms circulates from the "-" terminal via the "+"
terminal
Current direction
ALTERNATING CURRENT AND VOLTAGE
A voltage source that changes the polarity at regular intervals (cycles) generates a current which changes
direction constantly, this is referred to as alternating current (AC).
AC has some very useful characteristics It can easily be transformed into higher or lower values. This
characteristic makes it possible to transmit AC economically over long distances. As a result, AC generator
stations can be constructed as remote hydraulic power sources and supply the electricity to remote
consumers.
It is even possible to transform AC into DC for the rectification process.
This is the variation in alternating current, which is, it
first increases from zero to the maximum positive
peak, then decreases to zero and increases in
sequence to the maximum negative and back to zero.
The number of cycles that occur per second is
referred to as the frequency. The unit of measurement
of frequency is the Hertz (Hz). The normal frequency
of the domestic power mains supply (50 to 60 Hz)
means that there are 50 to 60 cycles repeated per
second.
Cycle

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SYMBOLS
STANDARD ELECTRICAL MAGNITUDES
Meaning
Direct current
Alternating current
AC/DC current
Example of 60 Hz single-phase alternating current
Example of dual-conductor direct current, 220v
OUTPUT
Power output is the necessary quantity of energy used or supplied by a body to perform work in a
determined time frame. It may also be defined as the work performed by the electrical current in a
determined time interval.
We use a wattmeter to measure the power
output of a device or we could calculate it
using the following formula:
P = U x I.
Whereby,
P = power output value in Watts
U = voltage value in Volts
I = current value in Amperes
Knowing the power output that a device consumes, the current that it is consuming can be calculated by
means of the following formula: I = P ÷ U. The power output can be measured in various ways depending
on the analysis requirements. We shall use the example of audio equipment.
RMS power output (Root Mean Square): is the average or actual power output that the device reproduces
continually.

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PMPO power output (Peak Music Power Output): is the power output that the device reproduces at
specific moments with the musical peak. This reflects only instantaneous values.
Meanwhile, we cannot compare them since they are measurements for different scenarios. What we should
do is compare values of the same type of measurement.
DESIGNATION SYMBOL
Unit Watt W
Multiple
Decawatt daW
Hectowatt hW
Kilowatt kW
Megawatt MW
ELECTRICAL RESISTANCE
Electrical resistance is the opposing force from matter to the flow of electric current. All electrical and
electronic devices have a certain resistance to the flow of electric current.
When the atoms of matter release free electrons
amongst themselves easily, the electric current
flows easily through the matter. In this scenario, the
electrical resistance of this matter is low.
On the other hand, in matter whose atoms do not
release free electrons amongst themselves with
ease, the electric current flows with difficulty,
because the electrical resistance of the matter is
high.
Therefore, the electrical resistance of a matter is a function of the ease or difficulty with which the matter
releases charge for circulation. Examples of the use of electrical resistance: heating in the water heater of
a shower, an iron, a soldering iron, a hair-dryer and illumination of light bulbs.
UNIT OF MEASUREMENT OF ELECTRICAL RESISTANCE

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The unit of measurement of electrical resistance is the Ohm, represented by the Greek letter Ω
(pronounced omega). The table below lists the multiples of the Ohm, which are the commonly-used values.
Multiple
Megaohm MΩ 1 MΩ or 1,000,000 Ω
Kiloohm kΩ 1 kΩ or 1000 Ω
Unit Ohm Ω _
The symbol used to represent the intensity of the electrical resistance is the letter R.
To convert the values, the same procedure used for other units of measurement is used.
ELECTRICAL RESISTANCY
Electrical resistancy is the specific electrical resistance of a particular conductor, with a length of 1 m, 1
mm² cross-section surface area, measured in a constant ambient temperature of 20°C.
The unit of measurement of resistancy is the ρ mm²/m, represented by the Greek letter ρ (pronounced
"Ro").
The table below lists some matter with its respective resistancy values.
MATERIALS Ro (ρ mm²/m A 20ºC)
Silver 0.016
Copper 0.0173
Gold 0.023
Aluminium 0.0265
Zinc 0.06
Nickel 0.095
Tin 0.114
Iron 0.122
INFLUENCE OF TEMPERATURE ON RESISTANCE
For the majority of matter, the increase in temperature means better electrical resistance.

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This is because with an increase in temperature, there is an increase in the agitation of the particles
comprising the matter, increasing the collisions between particles and the free electrons inside the
conductor.
CIRCUIT PROTECTION
Concept of the short-circuit
When the initial path of the current is deviated by a circuit whose resistance is virtually zero, it is referred to
as a short-circuit.
USE OF FUSES
The fuse protects circuits from high-intensity currents.
When a fuse blows, it is important to identify the cause
of the excessive current and resolve it. The rating of the
replacement fuse must be identical to that of the
original fuse.
OHM'S LAW
Ohm’s Law establishes a relationship between the
electrical magnitudes: voltage (U), current (I) and
resistance (R) in a circuit.
We now have the following formula:
U=R x A, i.e.: voltage is equal to resistance multiplied
by current.
EXAMPLE OF THE USE OF OHM'S LAW
Calculate the resistance of a component supplied with a 2A current and a voltage of 12 V at the terminals.
Result: given that resistance R is equal to voltage U divided by current A, resistance is 6 (12 V ÷ 2 A).

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APPLICATION OF OHM'S LAW
We shall use Ohm's Law to determine the values of the voltage (U), current (I) or resistance (R) on a circuit.
To obtain the unknown value on a circuit, we need to know two of the values in the Ohm's Law equation: U
and I, I and R or U and R.
OHM'S SECOND LAW
The research of Georg Simon Ohm also concluded that the electrical resistance of a conductor essentially
depends on four factors, which are:
1. The material from which the conductor is fabricated (ρ),
2. Length (l) of the conductor,
3. Cross-section surface area (la),
4. Temperature inside the conductor (t).
In order to be able to analyse the influence of each of these factors on electrical resistance, various
experiments were carried out, varying just one of the factors and maintaining the other three as constants.
It was thus discovered that:
"Electrical resistance is directly proportional to the length of the conductor".
"The electrical resistance of a conductor is inverselyproportional to its cross-section surface area".
U
R A
U = R x I
V = Ω x A
R = U / I
Ω = V / A
I = U / R
A = V / Ω

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SERIES AND PARALLEL CIRCUITS
In electrical applications, there are two types of main circuit: series circuits and parallel circuits.
SERIES CIRCUIT
The current follows a single path and flow through
the components one after another. The current is
identical at any point in the circuit.
The total voltage at the terminals of the consumers
is equal to the sum of the voltages at the terminals
of each consumer.
The corresponding total resistance is equal to the
sum of the individual resistances.
PARALLEL CIRCUIT
The current is divided so that it flows through the
components located in different branches. The
voltage is identical on each of the branches. The
total current is the sum of the current flowing in all of
the branches. The equivalent total resistance is
lower than the smaller individual resistance.
CONCEPTS OF MAGNETISM AND ELECTROMAGNETISM
Series circuit
Parallel circuit
R=p . I/a
"l" (length)
"a"(cross-section
area) "ρ" (material)

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MAGNETS
The properties of magnetic bodies are widely used
in electrical applications, in motors and generators
and in electronics in metrology instruments and
signal transmission.
There are two types of magnet:
The properties of magnetic bodies are widely used
in electrical applications, in motors and generators
and in electronics in metrology instruments and
signal transmission.
There are two types of magnet:
Natural magnets - Some naturally-occurring materials have natural magnetic properties. Magnetite, for
example, is an example of a natural magnet.
Artificial magnets - Comprised of bars of ferrous materials magnetised by man via artificial processes.
MAGNETIC FIELD
The area around the magnet in which the magnetic
forces are active is known as the magnetic field.
The effects of attraction and repulsion between two
magnets or attraction of one magnet to ferrous
materials owe their existence to this magnetic field.
In the diagram, we can see the lines of magnetic force, also referred to as induction lines.
Note that the largest concentration of filings is located in the region of the magnet poles. This is due to
the greater magnetic intensity at the polar regions, since the lines of force are concentrated here.

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ELECTRO-MAGNETISM
Electricity and magnetism are related phenomena.
Furthermore, the flow of an electric current through a
cable coiled around a wire core produces a magnet.
When the current is disconnected, the magnetic field
disappears. This magnet is known as an
electromagnet.
Electro-magnetism
COIL AND MAGNETIC FIELD
To obtain magnetic fields with a greater intensity from an electric current, simply roll the conductor in the
form of windings, one next to the other and spaced apart equally to form a coil or solenoid.
The table below shows a coil and its respective symbols.
COIL, COILED OR
INDUCTOR
SYMBOL
(PREFERRED FORM)
SYMBOL
(OTHER FORM)
Coils increase the magnetic effects generated at
each of the windings. The figure below shows a coil
comprised of various windings, illustrating the effect
resulting from the combination of the individual
effects.
DID YOU KNOW THAT:
The magnetic poles formed by the magnetic field of a coil have characteristics identical to those of
the poles of a natural magnet? And that the intensity of the magnetic field inside a coil depends
directly on the intensity of current and the number of windings?

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The core is the central part of a coil. The
arrangement of ferrous material inside the coil is a
means used to obtain improved intensity of the
magnetic field of said coil. In this scenario, the
combination of iron-core coils is known as an
electromagnet.
ELECTROMAGNET APPLICATION: RELAYS
A relay is an electromagnet application. It comprises a coil supplied by a control circuit and a contactor
opened by a spring. When the control circuit contactor is closed, the current flows through the coil. The coil
becomes an electromagnet and attracts the contactor to close it.
Relay application
The use of a low current inside the relay coil controls the flow of a high current in the power circuit. On a
vehicle, a relay reduces the length and circular cross-section requirements for harness cables, reducing the
current at the contactors and in the harness.

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MEASURING INSTRUMENT
To measure the load on a circuit, we use a commonly-used measuring device; the digital multimeter and
the electronic multimeter. Let's take a look at them:
DIGITAL MULTIMETER – Measurement of current (amperage) and tension (voltage). Used only for making
small checks on the electrical system.
ELECTRONICMULTIMETER – The electronic multimeter comprises a more complex circuit, providing a
greater accuracy of measurement, with analog or digital display
MULTIMETER
It is also known as a Multitest or Meter. In electronics, the measurement of different electrical magnitudes
at various points in a circuit is very common. Here, there is a need for a versatile instrument capable of
performing such measurements.
The multimeter is an electronic measurement instrument, using electrical contact, with analog or digital
scales of measurement. It is an instrument capable of measuring the main magnitudes, such as voltage,
current and resistance.

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ELECTRONIC MULTIMETER
The electronic multimeter comprises a more complex circuit, providing a greater accuracy of measurement,
with analog or digital display.
MEASUREMENT USING A MULTIMETER
In electro-electronics, calibrations and circuit maintenance are performed, for which the correct use of the
multimeter is essential for accurate measurements and maintenance of the instrument. Measurement using
a multimeter is the process by which measurements of the main electrical magnitudes are obtained, such
as voltage, current and resistance.
Let's take a look at the magnitudes we can measure:
 Alternating electrical voltage (volts AC)
 Constant electrical voltage (volts DC)
 Alternating electrical current (AC current)
 Direct electrical current (DC current)
 Electrical frequency (Hz)
 Pulse width (ms)
 Duty cycle as a % (duty cycle %)
 Engine rotation speed (rpm)
 Temperature (ºC)
 Dwell angle
 Semiconductors (diodes)
 Electrical resistance (Ohms)
 Electrical continuity (sound or beep test).
BATTERY
Batteries are devices which accumulate electrical energy by means of lead-acid chemical reactions that,
despite dating back over 200 years and being rediscovered by Alessandro Volta in 1800 AD, continue to be
unparalleled in their practicality and cost/energy production ratio.
Comprising six blocks of lead plates (positive and negative), immersed in a solution of sulphuric acid,
arranged inside a plastic case (polypropylene), the purpose of the battery is to accumulate electrical energy
which itself is generated across the terminals.

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APPLICATION SPECIFICATIONS
Batteries are classified according to three categories:
Automotive: uses high current in a short interval.
Stationary: uses low current over a long interval.
Traction: uses electrical current in a varied manner over a long period.
The incorrect use of batteries for the application may result in the loss of efficiency and a reduction in
service life.
APPLICATION AS A FUNCTION OF REGIME FOR USE
Normally, starting a car consumes a large amount of current; hundreds of Amperes, over a time period of
no longer then ten seconds. In this scenario, to do this, the battery being used must have a high discharge
of start-up current.
When its use entails a more constant discharge, for audio applications for example, which consume low
current but over a long time period, a battery with good deep-cycle performance is required.
BATTERY CONSTRUCTION
Here, we are going to learn about the construction of batteries, how they work and the types available on
the market.
COVER
The battery cover plate keeps the cells sealed, preventing electrolyte from escaping from inside the battery
to the external environment and prevents the ingress of foreign bodies.
CONVENTIONAL COVER PLATE – has a gas vent
tube connected directly across the cells, which
results in a greater evaporation of electrolyte due to
the flow of gas
Maximum
Minimum

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SEALED COVER PLATE – this cover plate has the
gas exhaust interconnected by means of a labyrinth
system, which promotes the condensation of gas
and the reduction of the increased evaporation of
gas, recovering in the form of water.
FLAME-RETARDANT COVER
Its purpose is to prevent sparks or flames from entering the battery, which would thus cause it to explode
PLATE COMPONENTS
1. Positive plate
2. Negative plate
3. Separator
4. Plate connector
5. Plates connected in series
6. Charge indicator
Grid - Made from lead alloy, its purpose is to conduct electrical current and act as a support for the mass.
Its rounded corners avoid the need for drilling the isolator.
Mass - Active substance of the battery, whose function is to accumulate chemical energy to transform it
into electrical energy. The greater the quantity of mass, the greater the capacity to accumulate
energy inside the battery (Ah).
Plates - Assembly formed from the grid plus the active mass from the positive and negative plates. Its
function is to generate 2.10 V, regardless of the quantity contained in each cell.

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As the number of plates inside the plate block increases, the current supply capacity at the moment the
vehicle is started, known as the start-up current, also increases, and is measured by the CCA test (to be
discussed later).
Comprising six blocks connected in series, the battery has a total voltage of 12.60 V when fully-charged.
The increase in CCA of a battery is associated with the increase in the face-to-face contact the plates have
between them, i.e.: the contact area of the acid with the numberless plates arranged inside the blocks.
The greater the face-to-face contact of the plates, the greater the ionic exchange, which results in greater
electrical current supply potential.
Note 1: The CCA number (cold cranking amperage) of a battery is its capacity to supply a specific start-up
current to the vehicle, at a determined temperature, in compliance with the final voltage in normalised
condition.
CCA test: this is regulated by the international SAE J537 standard and determines the electrical current to
be supplied by the battery for 30 seconds, maintaining the final voltage at 7.2 Volts or higher, at a
temperature of -18°C (Celsius) or 0°F (Fahrenheit).
Note 2: The CA number (cranking amperage) is another battery specification and is also a test without a
regulated standard, which calculates the battery current at a temperature of 25°C.
Note 3: The CA cannot be compared against the CCA.
Lead alloys - Grids are fabricated from lead alloy, which has other chemical elements mixed into its
composition. The purpose of the elements added to the lead is to provide protection against the corrosive
action caused by the acidic solution.
The main lead alloys are:
 Lead-Antimony (PbSb)
 Lead-Silver Calcium (PbCaAg)
COMPOSITIONS AND CHEMICAL REACTIONS
Composed of 35% sulphuric acid and 65% distilled water. This solution is essential for the chemical
reactions to occur.

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ACTIVE MASS
Material responsible for storing the energy in the battery. The greater the quantity of mass, the greater the
quantity of energy the battery can store. The active material of the positive plate is lead oxide (PbO2) and
for the negative plate it is pure sponge lead (Pb).
A chemical compound is mixed in with the mass, known as an additive, which increases durability and
reduces battery recharging time.
It improves the battery charge acceptance specification, standardising the positive plate surface area
known as the "layer of corrosion".
The best acceptance of charge favours the least depth in the battery cycle.
SPACER
Insulated material, fabricated from microporous polyethylene. Prevents contact between the positive and
negative plates. The meshes allow greater movement of acid around the positive plates thus ensuring
greater ion exchange.
The mechanical resistance of this material is greater, ensuring that it is not ripped or perforated easily by
friction from the plates.
CONNECTION OF THE PLATES
This piece joins the plates for forming the block
plates and interconnects all other blocks across the
cells, providing electrical continuity across the
battery terminals. With high mechanical resistance,
the connections are welded by melting the lead
(electric discharge), eliminating failures in the joining
of parts and increasing the electrical conductivity.
CHARGE INDICATOR
The Charge Indicator (charge eye) is recessed in the cover and, as its name suggests, is simply a device to
indicate the charge status of the battery. It must not be used as a fault indication tool.
Its operation is based on the principle of measuring the density of the acid solution, such as a densimeter.
A sphere fluctuates when the solution is very acidic, appearing in green in the viewfinder. When the
solution is less acidic, the sphere disappears from the field of vision, showing as black in colour. And when
the solution level is below the minimum level, the viewfinder shows as clear in colour.

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When the battery shows as clear in colour in the viewfinder, do not recharge or test it. By being fault-
specific, it may result in the battery exploding if subjected to electrical currents.
SAFETY INFORMATION
The use of safety goggles is recommended.
Read and complete all of the warranty certificate.
Keep out of the reach of children.
Caution: corrosive liquid.
Avoid sparks and flames in the proximity of the product.
Risk of explosion.
Recyclable product - return to the point of sale when replacing.
Do not dispose of in domestic waste. Contains toxic substances (lead).
Green - charge status greater than 65%.
Black - battery discharged.
Clear - battery electrolyte level below the
minimum level.

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STORAGE
Check the voltage periodically: Batteries with a voltage below 12.30 V (or dark viewfinder) must be
recharged.
 Maximum stacking (to avoid damaging the first battery in the stack):
 Up to five batteries in the lightweight line (up to 90 Ah);
 Up to three batteries in the heavyweight line (above 90 Ah).
 Storage on wooden pallets preserves the battery boxes;
 Never store tilted at an angle of more than 45° to avoid acid filtration.
 Dry and covered location, protected from sunlight and rain;
 Temperature between 10°C and 35°C.
 FIFO (First in first out): the first battery to be put into storage must be the first out. Prevents
recharging costs and ageing batteries.
RECHARGING YOUR BATTERIES
General care during recharging:
 Monitor the entire recharging process carefully,
 Never recharge batteries with a clear test indicator,
 Monitor the battery temperature; this should never exceed 50°C. Should this occur, stop
recharging until the battery has cooled and resume charging with a reduced charge rate,
 It is not recommended to recharge overnight without monitoring,
 Never disconnect the connection cables with the charger connected.
Care when preparing the circuit;
 Maintain a minimum gap of 2 cm between batteries,
 Place on the same circuit only batteries of the same capacity and state of charge (voltage) - for
connections in series,
 Never connect the positive terminal to the negative terminal on the same battery or series
connection,
 Before plugging in the charger, check that the connections (leads) are in contact correctly ,
 Also check that the charger is in good working order.

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CURRENT DRAIN TEST
This test consists in determining the quantity of energy lost from the battery when the vehicle engine is
switched off; many electronic devices need to remain switched on, however, in order not to lose their
configuration. Known as current drain, the energy consumed by this function is limited, which in some
cases may be much higher than the value set by the installers and could discharge the battery rapidly thus
reducing its service life. Here is how to perform the test:
 Switch off the engine and all vehicle electrical accessories.
 Connect a multimeter set to the current scale (Amperes), setting it to the highest range, in series
with the battery negative cable (respect the polarity);
 Setting the range to obtain a reading requires the current drain value; check the vehicle service
manual to determine the maximum current drain value;
 High current drain values may discharge the battery.
BASIC STRUCTURE OF THE ALTERNATOR
An alternator comprises the following basic components:
a three-phase winding in the stator, as immobile part of
the conductors, a rotor, around whose axis are located
the magnetic poles with the exciter winding, thus with
(on most types) two slip rings, two bearings, six power
output diodes and three exciter diodes and finally, two
brushes attached to the slip rings through which flows
the excitation current from the stator coil to the exciter
coil, in a rotational motion. Terminals are used to form
the electrical connection between the alternator and the
vehicle power supply system.
Basic illustration ofan alternator
Exciter diodes
Power output
diodes
Brushes
Exciter winding
Stator
winding
Slip rings

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Claw pole
half-piece
Exciter
windings
Claw pole
half-piece
Rotor shaft
Stator
winding
Drive pulley
Fan
Claw-pole
rotor
Housing
Brush
Bearing
Slip ring
Diode
Cooling
brace
ALTERNATORS WITH CLAW-POLE TYPE ROTOR AND SLIP RINGS
The name comes from the alternator arrangement, which consists of two halves, between which the
annular exciter winding is located. Each half has three claw poles which engage alternately resulting in a
total of 12 poles (6 north poles and 6 south poles),
From one pole to the other a field of force lines is formed, that during the rotary motion of the
rotor cuts off the three force lines from the stator winding, resulting in 12 pole switches in one rotation
(360°) of the rotor. Each pole pass generates a semi-cycle of electrical current alternately in a positive and
negative direction.
As a result, 12 x 3 = 36 voltage semi-cycles are induced in the three stator phases.
The diagram below shows in more detail the parts of a K1 claw-pole alternator.

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VOLTAGE REGULATOR
To maintain a constant alternator voltage, we use voltage
regulators.
The voltage produced in the generator is relatively equal to the
product of the rotation and of the excitation current. The principle
of voltage adjustment consists in controlling the excitation current
so that the terminal voltage of the alternator is kept constant up to
the maximum current, with variable load and rotation.
When the voltage exceeds the maximum indicated value, the
voltage regulator reduces or switches off the excitation current
completely. Excitation of the alternator is reduced and with it the
voltage generated by the alternator.
This occurs so quickly, that the alternator voltage is practically set
to the desired constant value, not having any visible light
scintillation.
ELECTRONIC REGULATORS
For medium and high-power alternators, electronic controllers are used, with which it is possible to control
the high excitation currents of the alternators in complete safety; in addition to this, they are highly-durable
(wear-free operation). Electronic regulators have transistors and Z diodes (Zener diodes) as semi-
conductor elements. Inside the alternator, the main transistor of the voltage regulator switches the
excitation field on and off alternately, in a rapid sequence.
Z DIODE (ZENER DIODE)
Another semi-conductor component, also very important in
the electronic regulator, is the Z diode, formerly referred to
as the Zener diode, after its inventor. This diode operates
only within the scope of locking, being that, with a certain
voltage (Zener voltage), locked current suddenly increases.
Therefore, the Z diode is quite suitable for issuing
measurement values. It is used in the transistorised
regulator to control another transistor once the
measurement voltage is reached.

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ADJUSTMENT OF TRANSISTORISED VOLTAGE
The transistorised regulator, in simple terms, operated in the following manner:
Starting from terminal D-, an electrical current flows through R3, T1 main transistor base, transmitter "E" of
the same and reaches terminal D+ (resistor "R3" protects against short-circuits between D- and D+). With
this, length C-E becomes a conductor, the excitation current now flows from D-, exciter winding, DF
connections, C-E section and reaches D+. The alternator now reaches total excitation and the voltage
increases.
The alternator voltage will also have the voltage splitter "R1-R2", which, in turn, provides the Zener voltage.
When the voltage reaches approximately 28 volts, the voltage in resistor R2 will be equal to the Zener
voltage and the Z diode will become a conductor.
The Z diode connects the "T2" control transistor. The base of main transistor "T1" will remain connected to
terminal D+ via transistor T2. There will be no more base current step. Therefore, main transistor "T1" will
open the excitation current circuit.
The alternator will then stop being excited. The voltage will drop to less than the theoretical value and the Z
diode will interrupt the base current of transistor "T2". With this, the base of the main transistor "T1" will be
connected via resistor "R3" to terminal "D+". The main transistor "T1" will connect the excitation current.
This is repeated in rapid sequences, generating a very accurate regulated voltage.

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ELIMINATION OF FAULTS
In the event of faults on the current generating equipment, it should be taken into consideration that it is not
always the alternator or the voltage regulator that are at fault. It could be the battery or conductors, etc. that
are at fault.
For any breakdowns that may occur, see further the possible causes and the respective means of
correcting them.
FAULT POSSIBLE CAUSES
Current less than the charge current  Defective voltage regulator.
The warning light illuminates when the ignition key
is turned to the OFF position (engine stopped).
 Fault on the voltage regulator.
 Short between the spirals or the earth in the
stator winding.
 Diodes in short-circuit.
The warning light illuminates (faint) when the engine
is accelerated.
 One or more burned out positive rectifier
diodes (in short-circuit).
The warning light does not illuminate when the
engine is stopped.
 Check the connections: engine earth strap to
the bodywork, battery leads.
 Exciter diodes open.
 Positive diodes open.
The warning light does not illuminate when the
engine is stopped.
 Bulb blown or disconnected.
 Voltage regulator disconnected.
 Battery completely discharged or damaged.
 Rotor winding broken.
The warning light illuminates faintly and does not
alter.
 Alternator field circuit broken.
 DF terminals disconnected.
 Brushes with poor contact.
 Detached slip ring.
The warning light lights up constantly with
unchanging brightness (bright).
 Terminal D+ in short-circuit to earth (as a
result the excitation diodes burn out).
 Terminal DF in short-circuit to earth.
 Short-circuit to earth or across the spirals of
the rotor winding.

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STARTER MOTOR
Internal combustion engines do not have the power to
start themselves; a drive device is required for
starting them, i.e.: a starter motor.
When starting, there is great resistance due to
compression and the friction of the piston, connecting
rod, crankshaft and bearings. The colder the engine
the greater the friction resistance.
The purpose of the starter motor is to rotate the
engine at a minimum number of rotations between 40
and 80 RPM for petrol engines and 100 to 200 ROM
for diesel engines. This is to achieve the ideal air-fuel
mixture, and for diesel engines the necessary
temperature inside the combustion chamber.
Starter motors are made up of the following components:
 Electric starter motor (some types have reduction gear).
 Solenoid with electrical connections (some types have an additional control relay).
 Mechanical pinion gear system.
ELECTRIC STARTER MOTOR
Electrical current is used in the electric starter
motor to generate rotational movement.
Electrical energy is converted into mechanical
energy. This is due to the fact that a conductor
with electrical current flowing through it exerts
a force in a magnetic field.
For better understanding, in the schematic
diagram below the conductor is represented by
a spiral which can rotate freely in the magnetic
field.
If an electrical current flows through this spiral, it is aligned perpendicularly to the magnetic field and is held
in this position by magnetic force. But if the direction of the current in the spiral is reversed during this
deadlock, its immobilisation can be prevented.
Brushes
Magnet
Spiral
Commutator

Basic Electricity
Page 34 of 42
The torque is then always in the same direction of rotation and allows for continuous rotation of spiral. This
current inversion is carried out in a collector which in this case comprises two semicircular segments
isolated from each other, to which the two ends of the spiral are connected. Two carbon brushes are
connected to the voltage source and thus electrical current flows through the individual spirals.
To obtain even torque, the number of spirals is increased. Their individual torques combined generate a
much higher and more uniform total level of torque.
SOLENOID
The basic function of the solenoid is to generate high currents from relatively low electrical currents.
On many types of solenoid, the coil comprises two windings: one for attraction and one for retention. The
diagrams below show the construction of a solenoid.
The advantage of this type of solenoid is a greater heat resistance.
Under the action of the magnetic field, the mobile core is attracted to the inside of the coil: the terminal
bridge contact is closed. There is a perfect contact thanks to the spring between the locking ring on the

Basic Electricity
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mobile core shaft and the bridge. The recoil spring makes the contacts open after the key is deactivated. In
solenoids for starter motors, the course of movement is also used to move the pinion in the axial direction.
COUPLING SYSTEM
The starter motor side bearing has a coupling system, with a pinion, free-running gear, gear member and
engagement spring.
On these starter motors, the forward movement of the pinion generated by the solenoid and the rotational
movement of the starter motor are sufficiently combined and transmitted to the pinion.
GEAR WHEEL
The starter motor engages a small gear - known as a pinion - on the engine flywheel ring gear. The high
transmission ratio (normally between 10:1 and 15:1) enables the engine resistance to be overcome. It is
therefore possible to keep the dimensions of the starter motor very small and its weight very low.
When the engine starts to run, the pinion should be disengaged automatically to protect the starter motor.
GEAR MECHANISM
The gear mechanism should be such that the forward movement of the pinion generated by the solenoid
and the rotational movement of the starter motor can act in conjunction with all possible gearing situations,
nevertheless independently. The various sizes of starter motor can be differentiated between, including
through the technical execution of the gearing mechanism. The differences are highlighted in the naming of
the type of starter motor.
FREE-RUNNING GEAR
On all types of starter motor, the rotational movement is transmitted via a free-running gear. The free-
running gear acts so that, with the armature shaft actuated, the pinion is also moved forward and that, with
the pinion rotating more quickly (internal combustion engine "overtaking" the speed of the pinion), the
engagement of the pinion and the armature shaft is released.
The free-running gear or clutch is arranged between the starter motor and the pinion and prevents the
starter motor armature from reaching very high rotational speeds due to acceleration of the internal
combustion engine.

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ROLLER FREE-RUNNING GEAR
You will see in the diagram below that when the
armature shaft is actuated, the rollers are
engaged in the smallest space, thus establishing
a solid mechanical connection.
At the moment that the force is reversed due to
the acceleration of the internal combustion
engine, the rollers are withdrawn and are pushed
- against the force of the springs - to the area
with more space. This is how the mechanical
connection between the armature and the starter
motor pinion is disengaged.
When in rotation, the armature shaft acts so that the rollers are engaged in the smaller space.
When the internal combustion engine starts to run, the starter motor pinion is actuated with more rotational
speed than that of the starter motor armature under no load; this makes the rollers of the free-running gear
unlock and - against the force of the springs - move to the widest part of the roller sliding curve. Thus the
mechanical connection between the pinion and the armature is disengaged.
The great advantage of this free-running gear is that only small masses with a fairly low weight need to be
accelerated and that the starting torque of the combustion engine is relatively small.
ELIMINATION OF FAULTS
Many faults attributed to the starter motor, battery, relays, wiring, contacts or earthing connection may be
caused by the ignition system or fuel supply, etc.
The guidance for eliminating defects that we are going to step through covers only the starter installation.
DISADVANTAGES CAUSES
Roller sliding curve
Spring
Roller
ring
Coupling ring
Pinion shaft
Pinion
Direction of
coupling

Basic Electricity
Page 37 of 42
Solenoid is not actuated.
 Damaged solenoid.
 Connections between the starter key and the
solenoid are interrupted.
 Damaged solenoid.
The armature rotates, but the pinion does not
engage (makes a noise).
 Pinion shaft is seized.
 Pinion or ring gear has damaged or burred
teeth.
The pinion engages, the armature rotates but the
flywheel does not.
 The pinion sprag (free-running gear) is
slipping.
The starter motor continues to turn over after the
starter key has been released.
 The starter key is not disconnected.
 Solenoid in short-circuit.
Pinion does not disengage after starting.
 Recoil spring weak or broken.
 Pinion seized.
Starter motor operates normally but makes a
noise when disengaging.
 Pinion free-running gear stiff.
EXERCISES

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Page 38 of 42
1) Convert the given unit of measurement into the required unit:
1. 3.75 V = _ _ _ _ _ mV
2. 0.6 V = _ _ _ _ _ mV
3. 200 mV = _ _ _ _ _ _V
4. 0.05 V = _ _ _ _ _ _ mV
5. 1.2 A = _ _ _ _ _ _mA
2) Let us suppose that a light uses a 12 V power supply and has a resistance of 100 Ω. What is the value
the current circulating at the light when it is switched on?
U = 12 V
R = 100 Ω
I = ?
3) Let us also suppose that the motor of a toy race car reaches a maximum speed of rotation from being
supplied with a 9 V power source. In this scenario, the motor current is 230 mA. What is the resistance
of the motor
U = 9 V
I = 230 mA (or 0.23 A)
R=?
4) Let us also suppose that a 22 kΩ resistor was connected to a power source with an unknown output
voltage. A milliammeter connected in series in the circuit indicates a current of 0.75 mA. What is the
power source voltage output?
I = 0.75 mA ( or 0.00075 A)
R = 22 KΩ (or 22,000 Ω)
U = ?
5) Draw a single circuit using a bulb.

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6) Draw a single circuit using two bulbs.
7) Draw a parallel circuit using two bulbs.
8) Measure the resistance of the ignition wires.

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9) Measure the battery voltage.
10) Measure the battery amperage.
11) Draw two batteries in series and measure the voltage and the amperage.

Basic Electricity
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12) Draw two batteries in parallel and measure the voltage and the amperage.
13) Describe the procedure for measuring a current drain.
14) Describe the procedure for testing the battery during engine start-up.

Basic Electricity
Page 42 of 42
15) Dismantle and check the starter motor.
16) Dismantle and check the starter motor.

Tti basic electricity level 1

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