TRANSFORMER

Contents:•History

•What is a Transformer•How it is USED•Who invented•Principle

•Type of Transformer•Equation of Transformer

HistoryA varying current in the first or primary winding creates a varying magnetic flux in the transformer's core and thus a varying magnetic field through the secondary winding.

HistoryThis varying magnetic field induces a varying electromotive force (EMF), or "voltage", in the secondary winding. This effect is called inductive coupling.

WHAT IS A TRANSFORMER?A transformer is a device that transfers electrical energy from one circuit to another through inductively coupled conductors—the transformer's coils.

How it is used?A transformer is used to bring voltage up or down in an AC electrical circuit. A transformer can be used to convert AC power to DC power. 

There are transformers all over every house, they are inside the black plastic case which you plug into the wall to recharge your cell phone or other devices. 

Responsible for the

Development of

TRANSFORMER

William Stanley, Jr. (USA)•He contributed to the development of an alternating current induction motor. 

Lucien Gaulard (France)(1850 - November 26, 1888) invented devices for the transmission of alternating current electrical energy.

Sebastian Ziani de Ferranti (England)

 who promoted the installation of large electrical generating stations and alternating-current distribution networks in England.

TRANSFORMERPower converter that transfer electrical energy from one circuit to another through inductively.

Principle transformer is based on two

principles: (1) that an electric current can

produce a magnetic field ( electromagnetism)

(2) that a changing magnetic field within a coil of coil induces a voltage across the ends of the coil

( electromagnetic induction)

TYPES OF TRANSFORMER

Step Up Transformer

Step Down Transformer

Step Up TransformerThis type of transformer converts low voltage of high voltage at low current.

PrimaryThe primary coil is made of thick copper wire while the secondary coil is made of thin wire.

SecondaryThe number of turns in the secondary coil is greater than the number of turns in the primary coil.

Step Down TransformerIf we assume there is no loss of power,Out put power = Input powerEsIs = EpIp = K

If a load is connected to the secondary winding, current will flow in this winding, and electrical energy will be transferred from the primary circuit through the transformer to the load. In an ideal transformer, the induced voltage in the secondary winding (Vs) is in proportion to the primary voltage (Vp) and is given by the ratio of the number of turns in the secondary (Ns) to the number of turns in the primary (Np) as follows:

The transformer equation:  

N1 = V1

N2 = V1

N1 = Number of turns on coil 1N2 = Number of turns on coil 2V1 = Voltage on coil 1V2 = Voltage on coil 2

Advantage of Alternative Current

Electric power distribution primarily used direct current at the same voltage used by motors and lights.

Changing direct current voltage level required rotating machinery which was costly to purchased and install.

Advantage of Alternative Current

BASIC TRANSFORMER

The basic transformer is an electrical device that transfers alternating-current energy from one circuit to another circuit by magnetic coupling of the primary and secondary windings of the transformer.

The voltage applied to the primary winding causes current to flow in the primary.

This current generates a magnetic field, generating a counter emf (cemf) which has the opposite phase to that of the applied voltage. The magnetic field generated by the current in the primary also cuts the secondary winding and induces a voltage in this winding.

TRANSFORMER CONSTRUCTION

A TRANSFORMER consists of two coils of insulated wire wound on a core. The primary winding is usually wound onto a form, then wrapped with an insulating material such as paper or cloth.

TRANSFORMER CONSTRUCTION

Transformer Consructions

The most common types of transformers are the shell-core and the hollow-core types. The type and shape of the core is dependent on the intended use of the transformer and the voltage applied to the current in the primary winding.

Exciting Current

When voltage is applied to the primary of a transformer, exciting current flows in the primary.

The current causes a magnetic field to be set up around both the primary and the secondary windings. The moving flux causes a voltage to be induced into the secondary winding, countering the effects of the counter emf in the primary.

Power of Transformer

A transformer with two or more windings wound on a laminated iron core. The transformer is used to supply stepped up and stepped down values of voltage to the various circuits in electrical equipment.

Power of Transformer

Application The major application of transformer is to increase voltage before transmitting electrical energy over long distances through the wire.

Also used extensively in electronic products to step down the supply voltage to a level suitable for the low voltage circuits they contain.

Activity Time

Question…..

If this is a step–up transformer, which side would be the secondary?A. RightB. Left

Correct AnswerIs (b.) LeftA step-up transformer raises voltage.The secondary would have more voltage and more coils: the left side.

Which side has the most CURRENT?A. Bottom

B.Top

A. Bottom because Power in must =

Power out, the side with the least

voltage must have the most current.

What type of currentmust be use

in transformer??A. AcB. Dc

Answer : A. AC A transformer transfers voltage by transferring magnetic flux. Magnetic flux occurs with changing

magnetism and changing current: Alternating Current.

Problem Solving1.A transformer has 100 turns on coil 1 and 200 turns on coil 2.*What will the voltage on coil 2 be

if the voltage on coil 1 isi. 10 volts?

ii. 200 volts?iii. 1000 volts?

Created By:Mallillin, Khate A.•IV-2•Fernandez, Mariel•IV-2•Aguilar, Marry Grace•IV-2•

References:

• http://www.physicstutorials.org/home/magnetism/transformers

• http://www.worsleyschool.net/science/files/transformers/page.html

• http://www.tpub.com/neets/book2/5k.htm

• *http://edisontechcenter.org/Transformers.html

Google