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8/3/2019 Basci Electrical

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CONDUCTORS

A CONDUCTOR is any material that easily allows electrons

(electricity) to flow.

A CONDUCTOR has 1 to 3 free electrons in the outer ring.

Because atoms with 1 to 3 electrons in the outer ring are held

(bound) loosely to the atom, they can easily move to another

atom or make room for more electrons.

Conductor material includes copper and gold.

INSULATORS

An INSULATOR is any material that inhibits (stops) the flow

of electrons (electricity).

An insulator is any material with 5 to 8 free electrons in theouter ring. Because, atoms with 5 to 8 electrons in the outer

ring are held (bound) tightly to the atom, they CANNOT be

easily moved to another atom nor make room for more

electrons.

Insulator material includes glass, rubber, and plastic.


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SEMICONDUCTORS

Any material with exactly 4 free electrons in the outer orbit are

called SEMICONDUCTORS.

A semiconductor is neither a conductor or insulator.

semiconductor material includes carbon, silicon, and germanium.

These materials are be used in the manufacturer of diodes,

transistors, and integrated circuit chips.


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The second Current Flow theory is:-

CONVENTIONAL THEORY

Conventional theory, also known as HOLE THEORY, states that current flows from POSITIVEto NEGATIVE. Protons or the lack of electrons (the holes) move towards the negative. (Current

flow direction in Hole Theory is the opposite of that in Electron Theory.)


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VOLTAGE

Voltage is the electrical force that moves electrons through a conductor. Voltage is electrical

pressure also known as EMF (Electro Motive Force) that pushes electrons.

The greater the difference in electrical potential push (difference between positive and

negative), the greater the voltage force potential.


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CURRENT (AMPERES)

CURRENT is the quantity or flow rate of electrons moving past a point within one second.

Current flow is also known as amperage, or amps for short.

Higher voltage will produce higher current flow, and lower voltage will produce lower current

flow.

Current flow is measured in units called Amperes or AMPS.


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AFFECTS OF CURRENT FLOW

Two common effects of current flow are Heat Generation and Electromagnetism.

HEAT: When current flows, heat will be generated. The higher the current flow the greater the heat

generated. An example would be a light bulb. If enough current flows across the filament, it will glow

white hot and illuminate to produce light.

ELECTROMAGNETISM: When current flows, a small magnetic field is created. The higher the

current flow, the stronger the magnetic field. An example: Electromagnetism principles are used in

alternators, ignition systems, and other electronic devices.


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RESISTANCE

Resistance is the force that reduces or stops the flow of electrons. It opposes voltage.

Higher resistance will decrease the flow of electrons and lower resistance will allow more electronsto flow.

Resistance is measured in units called OHMS.


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TYPES OF ELECTRICITY

Two basic types of Electricity classifications:-

STATIC ELECTRICITY is electricity that is standing still. Voltage potential with NO electron flow.

DYNAMIC ELECTRICITY is electricity that is in motion. Voltage potential WITH electron flow.

Two types of Dynamic electricity exist:-

1. Direct Current (DC) Electron Flow is in only one direction.

2. Alternating Current (AC) Electron flow alternates and flows in both directions

(back and forth).


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STATIC ELECTRICITY

Voltage potential with NO electron flow.

Example: By rubbing a silk cloth on a glass rod, you physically remove electrons from the glass rod and

place them on the cloth. The cloth now has a surplus of electrons (negatively charged), and the rod now

has a deficiency of electrons (positively charged).

Another example: Rub your shoes on a rug and then touch a metal table or chair .... Zap!! The shock

you felt was the static electricity dissipating through your body.


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DYNAMIC ELECTRICITY

is electricity in motion, meaning you have electrons flowing, in other words voltage

potential WITH electron flow.

Two types of dynamic electricity exists:-

DIRECT CURRENT (DC)

Electricity with electrons flowing in only one direction is called Direct Current or DC.

DC electrical systems are used in cars.


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SOURCES OF ELECTRICITY

Electricity can be created by several means: Friction, Heat, Light, Pressure, Chemical Action, or Magnetic

Action.

Only a few of these sources of energy are used in the automobile. The battery produces electricity throughchemical action, and the alternator produces electricity through magnetic action.

1. Friction creates static electricity.

2. Heat can act upon a device called a thermo couple to create DC.

3. Light applied to photoelectric materials will produce DC electricity.

4. Pressure applied to a piezoelectric material will produce DC electricity.

5. Chemical Action of certain chemicals will create electricity.


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MEASURING INSTRUMENT

A VOLTMETER measures the voltage potential across or parallel to the circuit.

The Voltmeter measures the amount of electrical pressure difference between two points being

measured.

Voltage can exist between two points without electron flow. Voltage is measured in units called

VOLTS.

Caution- An Voltmeter should not connected in series.


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An AMMETER measures the quantity of current flow. Ammeters are placed in series

(inline) to count the electrons passing through it. Current flow is measured in units called

Amperes or AMPS.

Caution- An Ammeter should not connected in parallel, if so then heavy current

flow through ammeter and it will get damaged.

AMMETER


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MEASUREMENT

An OHMMETER measures the resistance of an electrical circuit or component. No

voltage can be applied while the ohmmeter is connected, or damage to the meter willoccur.

OHMMETER


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MEGGER

It is a portable instrument used for testing the insulation resistance of circuit and for

measuring resistance of the order ofmega ohms.

Its range of voltage are- 500V, 1000V, 2500V, 5000V

There are two types of megger is a hand driven and electrical.

Minimum megger value of any equipment should not be less then one mega ohms

Hand driven megger Electrical megger


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CLAMP METER

A current transformer with a single conductor is used in combination with abridgerectifier & D.C ammeter (digital) to produce a very useful service meter called clamp

meter. The core can be split with the help of hinge therefore the core can be clamped

around life conductor to measure the current. Thus this arrangement avoids the necessity

of breaking the circuit in order that a current measuring device be inserting in series with

it to measure the value of current flowing.. By changing shunt resistance different range

of current can be measured.


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Different type of power supply system

1. Star connected 3 phase 4 wire system

2. Star connected 3 phase 3 wire system


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3. Delta connected 3 phase 3 wire system


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ELECTRICAL EQUIPMENTS

During the 1950s, the role of women was generally considered to be that of the'homemaker'. Bright television and magazine advertisements encouraged women to stay

at home and create a domestic haven for their families using the new appliances on offer.

These devices promised to raise standards of living and release housewives from the

shackles of household chores.

Electrical home appliances:-


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Electrical equipments in plant

An electric motor converts electrical energy into

mechanical energy. Most electric motors operate through

the interaction of magnetic fields and current-carrying

conductors to generate force. The reverse process,

producing electrical energy from mechanical energy, is

done by generators such as an alternator

Motor:-

Transformer:-

A transformer is a device that transfers electrical

energy from one circuit to another with out

electrically connected.


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Home Electrical Safety at home

Electricity is all around us especially in-doors. There are many things to remember in order

to be safe around electricity:-

Do not play with power points or appliances.

Do not play with power points. Power points can shock, give a zap that will hurt, burn or kill.Power points need to be protected where there are babies or small children.

Lots of electrical cords in one socket are dangerous.

Putting many plugs in one socket is dangerous. It is called "piggy-backing". Instead of

using a socket with many plugs, use a power board.


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Tell a responsible adult about broken electrical plugs or cords.

Always get an electrician to fix broken or damaged electrical equipment. To try to fix

electrical equipment yourself is dangerous.

Water and electricity do not mix. Together they are a very dangerous combination.

Never touch electrical appliances or switches with wet hands.

In the bathroom, make sure electrical appliances like hairdryers or shavers can not fall into

the bath or basin.

Keep extension cords, or portable appliances (like electric radios or televisions) away from

the bath or pool.


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BOILER OPERATION SYSTEM

I.D FAN

E.S.P

CHEMINY

RAPER

BOILER

CONVEYERTURBINE

Gener

ator

INLETSTEAM

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