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Step down Transformers
Even at the outset, please understand that a transformer is a device for stepping-up or stepping-down the voltage of an alternating electric signal. Without transformers, the transmission and distribution of AC electric power over long distances would not be feasible.
The basic purpose of step down transformers, as the very name indicates, is to reduce electrical voltage. This kind of transformer steps down the voltage as applied to by the user. For instance, a step down transformer becomes necessary when you wish to use a product needing 110v where the main supply is 220v. As a rule, a step-down transformer is a transformer whose secondary voltage is less than its primary voltage.
In other words, a step down transformer converts electrical voltage from a higher level or phase configuration to a lower level. They include many features such as electrical isolation, power distribution, and control and instrumentation applications.Step down transformers are designed on the principle of magnetic induction between coils to convert voltage and/or current levels.
The step down transformer is designed to reduce the voltage from the primary winding to the secondary winding. Likewise, a transformer designed to increase the voltage from the primary windings to the secondary windings is a step up transformer. This kind of transformer steps up the voltage to a higher voltage. A transformer in which the secondary voltage is higher than the primary is called a step-up transformer and if the secondary voltage is less than the primary, the device is known as a step-down transformer.
Step down transformers are usually made from two or more coils of insulated wire wound around a core which is of iron. When voltage is applied to one coil (frequently called the primary or input) it magnetizes the iron core, which induces a voltage in the secondary coil. Step down transformers often range in voltage sizes from 0.5 kva to 500 kva.
It is essential that electric transformers must be efficient and should dissipate as little power as possible in the form of heat during the transformation process. Increasing transformer efficiency and reducing heat is best achieved if you choose copper windings rather than aluminum or any other winding metals. Transformers with copper windings may certainly cost more initially, but saving on operational cost over time will compensate for the initial higher cost.
As a rule, power transformers are installed within sealed containers that have oil or another substance circulating through the windings to transfer the heat to external radiator-like surfaces.
A step down transformer finds application in many areas. The larger units are used in electric power systems, and the small ones in electronic devices. Industrial and residential power transformers that operate at the line frequency may be single phase or three-phase and are designed to handle high voltages and currents.
Power distribution requires high voltages and thus step up and step down transformers. Thus, power transmission requires a step-up transformer at the power-generating station to raise the voltages. At the supply point, step-down transformers are used to reduce the voltage and increase the current as will be required by the residential or industrial user.