Transformer facts for kids

Transformer

A transformer is a device that transfers electrical energy from one electrical circuit to another through mutual (electromagnetic induction) and without change in frequency. Transformers are an important part of electrical systems.

Transformers are made in many different sizes, from a very small coupling transformer inside a stage microphone to big units that carry hundreds of MVA used in power grids.

The main reason to use a transformer is to make power of one voltage level into power of another voltage level. High voltage is easier to send a long distance, but less voltage is easier and safer to use in the office or home. Transformers are used to increase or decrease alternating current (AC) voltage in circuits. The transformer is usually built with two coils around the same core. The primary coil or input coil is connected to supply side while secondary coil supplies power to load. The second one is called the output coil. Energy is transferred from the primary to the secondary by electromagnetism. In power grids many transformers are used. These are networks for delivering electricity from the generator and to the user.

The transformers in your neighborhood, on electricity poles, or the ones connected to underground wires, usually transform high voltage of 7,200 volts to 220-240 volts of electricity to power lights and appliances such as refrigerators in homes and businesses. Some countries, such as America use different voltages in homes, such as 120 volts. Transformers cannot increase power, so if the voltage is raised, the current is proportionally lowered. If the voltage is lowered, the current is proportionally increased.

Transformers inside electronics equipment provide the kinds of electricity the various parts need.

There are several basic types of transformers:

• Step-up transformer: the voltage output is greater than the voltage input.
• Step-down transformer: the voltage input is greater than the voltage output.
• Some transformers have the same output voltage as input voltage and are used to electrically isolate two electrical circuits.

Gallery

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  Utility pole transformers

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  Transformer in Melbourne, Australia

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  Distribution transformer in Taiwan

Images for kids

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  Pole-mounted distribution transformer with center-tapped secondary winding used to provide "split-phase" power for residential and light commercial service, which in North America is typically rated 120/240 V.

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  Instrument transformer, with polarity dot and X1 markings on LV side terminal

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  Power transformer overexcitation condition caused by decreased frequency; flux (green), iron core's magnetic characteristics (red) and magnetizing current (blue).

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  Interleaved E-I transformer laminations showing air gap and flux paths

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  Substation transformer undergoing testing.

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  An electrical substation in Melbourne, [[Australia

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  Camouflaged Transformer in Langley City

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  Transformer at the Limestone Generating Station in Manitoba, Canada

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  "E" shaped plates for transformer cores developed by Westinghouse

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  Real transformer equivalent circuit

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  Laminated core transformer showing edge of laminations at top of photo

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  Small toroidal core transformer

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  Windings are usually arranged concentrically to minimize flux leakage.

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  Cutaway view of liquid-immersed transformer. The conservator (reservoir) at top provides liquid-to-atmosphere isolation as coolant level and temperature changes. The walls and fins provide required heat dissipation.

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  Faraday's experiment with induction between coils of wire

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  Induction coil, 1900, Bremerhaven, Germany

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  Faraday's ring transformer

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  Shell form transformer. Sketch used by Uppenborn to describe ZBD engineers' 1885 patents and earliest articles.

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  The ZBD team consisted of Károly Zipernowsky, Ottó Bláthy and Miksa Déri

See also

In Spanish: Transformador para niños