Factors That Affect the Efficiency Transformers

7/31/2019 Factors That Affect the Efficiency Transformers

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Factors that affect the efficiency of transformers

The heating effect of current in a coil.Power is lost as heat I2R whereby I is the current flowing through the coil and R is the

resistance of the coil

Methods to increase the efficiency

Use thick copper wires of low resistance. Use coolant to decrease the temperature of thetransformer.

Heating effect of induced eddy currentsIn the iron core. When the magnetic field in the iron core fluctuates, eddy currents are

generated in the iron core.


Use a laminated iron core whereby each layer is insulated with enamel paint to prevent theflow of eddy currents. The high resistance between layers of the iron core decrease the

prevalence of eddy currents and heat.

Magnetization of the iron core.The energy used in the magnetization and de-magnetization of the iron core each time

current changes its direction is known as hysterisis. This energy is lost as heat which

subsequently heats up the iron core.


Use a soft iron core that is easily magnetized and de-magnetized.

Flux leakage.Some of the induced magnetic flux from the primary coil is not transmitted to the

secondary coil, therefore the e.m.f in the secondary coil is decreased.

The secondary coil(windings) are intertwined tightly with the primary coils. The iron core

should form a closed loop.


The secondary coil (windings) is intertwined tightly with the primary coils. The iron core


Transformer

Posted by Electromagnetism | 8:25 PM | efficiency, transformer| 0 comments
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[This image is original released underGNU Free Documentation license]

What is transformer?Transformer is a device that is used to raise or lower down the potential difference of an

alternating current.

Function:The function of a transformer is to increase or decrease the potential difference of analternating current supply.

Structure and Technical Terms1. A transformer consist of 3 parts, namely

1. The primary circuit

2. The core3. The secondary Circuit
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[This image is released under the GNU Free Documentation License.]

Primary Circuit:

The primary circuit is the circuit that connected to the input energy source. The current,

potential difference and coil (winding) in the primary circuit are called the primary current

(Ip), primary potential difference (Vp) and primary coil respectively.

Core:

The core is the ferromagnetic metal wound by the primary and secondary coil. The

function of the core is to transfer the changing magnetic flux from the primary coil to the

secondary coil.

Secondary Circuit:

The secondary circuit is the circuit that connected to the output of the transformer. The

current, potential difference and coil (winding) in the secondary circuit are called the

secondary current (Is), secondary potential difference (Vs) and secondary coil respectively.
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Working Principle of A Transformer

1. A transformer consists of a primary coil and a secondary coil wound on a soft ironcore.

2. When an alternating current flows in the primary coil, a changing magnetic flux is

generated around the primary coil.3. The changing magnetic flux is transferred to the secondary coil through the iron

core.

4. The changing magnetic flux is cut by the secondary coil, hence induces an e.m.f. inthe secondary coil.

5. The magnitude of the output voltage can be controlled by the ratio of the number of

primary coil and secondary coil.

Types of Current in A TransformerThe current in the primary circuit must be alternating current because alternating current

can produce changing magnetic flux. A changing magnetic flux is needed to induce e.m.f.in secondary coil.

The induced current in secondary is also an alternating current. The frequency of the

alternating current in secondary coil is same as the frequency of the primary current.

The alternating in the secondary circuit can be converted into direct current by using a pair

of diode.

Symbol of A Transformer

The figure on the left shows the symbol of a transformer.

The 2 lines in between the coil denote the core.
http://bp1.blogger.com/_PyvjcvYfRLk/SGBkX3vIIcI/AAAAAAAAAGY/SwOQdh1kf94/s1600-h/Transformer_symbol.png


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Types of Transformer

Step-up transformer

A step-up transformer is one where the e.m.f. in the secondary coil is greater than the e.m.f.in the primary coil. It is used to increases the potential difference. The number of windings

in the secondary winding is greater than the number of windings in the primary coil. The

current in the primary coil is greater than the current in the secondary coil.

Step-down transformer

Conversely, a step-down transformer is one where the e.m.f. in the secondary coil is less

than the e.m.f. in the primary coil. It is used to reduce the potential difference. The number

of windings in the primary winding is greater than the number of windings in the secondary

coil. The current in the primary coil is lesser than the current in the secondary coil.

Calculation of Potential Difference Change

Vp = input (primary) potential difference

Vs = output (secondary) potential differenceIp = input (primary) current

Is = output (secondary) current

Calculation of Current ChangeIdeal Transformer

Non-ideal transformer

Vp = input (primary) potential differenceVs = output (secondary) potential difference

Ip = input (primary) current

Is = output (secondary) current

Physics AnimationAppletTransformer - Molecular Expression

Transformer - ngsir.netfirms.com

Electromagnetic Oscillating Cirecuit - Walter Fendt
http://micro.magnet.fsu.edu/electromag/java/transformer/index.htmlhttp://www.ngsir.netfirms.com/englishhtm/Transformer.htmhttp://www.walter-fendt.de/ph14e/osccirc.htmhttp://micro.magnet.fsu.edu/electromag/java/transformer/index.htmlhttp://www.ngsir.netfirms.com/englishhtm/Transformer.htmhttp://www.walter-fendt.de/ph14e/osccirc.htm


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actors that affect the efficiency

The heating effect of current in a coil.Power is lost as heat I2R whereby I is the current flowing through the coil and R is the

resistance of the coil

Methods to increase the efficiencyUse thick copper wires of low resistance. Use coolant to decrease the temperature of the

transformer.

Heating effect of induced eddy currentsIn the iron core. When the magnetic field in the iron core fluctuates, eddy currents are

generated in the iron core.


Use a laminated iron core whereby each layer is insulated with enamel paint to prevent the

flow of eddy currents. The high resistance between layers of the iron core decrease the

prevalence of eddy currents and heat.

Magnetization of the iron core.The energy used in the magnetization and de-magnetization of the iron core each timecurrent changes its direction is known as hysterisis. This energy is lost as heat which

subsequently heats up the iron core.


Use a soft iron core that is easily magnetized and de-magnetized.

Flux leakage.Some of the induced magnetic flux from the primary coil is not transmitted to thesecondary coil, therefore the e.m.f in the secondary coil is decreased.

The secondary coil(windings) are intertwined tightly with the primary coils. The iron core



The secondary coil (windings) is intertwined tightly with the primary coils. The iron coreshould form a closed loop.

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Factors That Affect the Efficiency Transformers