They can be. The benefit of an auto transformer is it can be made smaller than a traditional transformer and have the same power rating - this is because some of the power in an auto is transferred via conduction, while in a traditional transformer all power is transferred via induction.
If the voltage ratio between High / low voltage is much above ~3, this size savings is lost. The highest ratio I've seen in an auto is 3.33. Many distribution Transformers convert voltage from 30-70kV to 2.4-13.8kV, so for many cases you will end up with a ratio in the 4-10 range, although I have seen some as low as 2.5.
Another Answer
Autotransformers are not used in the secondarydistribution system -i.e. they are not used to step down a high-voltage distribution voltage to a low-voltage distribution voltage- for two reasons.
Firstly, they do not provide electrical isolation between the high- and low-voltage systems. This is essential, for reasons of safety.
Secondly, should a break occur in the low-voltage part of the winding, the whole of the primary voltage will be applied to the load.
For this reason, autotransformers are restricted to transmission and (in some cases) primary distribution systems -i.e. they are used as power transformers, rather than as distribution transformers.
"Auto" refers to the single winding used an auto transformer.
in isolation transformer earthing is not provide on secondary side but in ordinary transformer neutral of secondary side is earthedAnswerAn isolation transformer is a 1:1 ratio transformer; its function is to electrically isolate the secondary side from the primary side without changing the voltage. An example of an isolation transformer is the one used in a shaver socket.A distribution transformer is a step-down transformer, used within the electricity network's distribution system. An example of distribution transformer is a pole-mounted transformer, supplying low voltage to residences.(Of course, all mutual transformers provide electrical isolation between primary and secondary.)
A '33-kV transformer' is a three-phase primary-distribution transformer, used in the UK's electricity system to step down the 33-kV primary-distribution voltage to the 11-kV secondary-distribution voltage -the lowest voltage used in the high-voltage distribution system. These transformers are categorised as 'power transformers', and are located in what are termed 'primary substations'.
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Dy1 means the vector group that is being used at a distribution system.
A distribution transformer IS the term used to describe the utility transformer which supplies a residence.
because autotransformer used for both purpose step up and step down but dustrubution need step down in case of this autotransformer not used for dustrubtion purpouseAnswerBecause an autotransformer (not 'auto transformer') does not provide electrical isolation between the secondary and primary.
auto transformer is a one winding transformer which is are used for step up and step down voltage without chang its power and friquncy
It's called a 'distribution transformer', as opposed to a 'power transformer' which is used in the transmission and primary-distribution electrical systems.
"Auto" refers to the single winding used an auto transformer.
Power transformers are step-up or step-down transformers used in the electricity transmission system, whereas distribution transformers are step-down transformers used in the electricity distribution system.
in isolation transformer earthing is not provide on secondary side but in ordinary transformer neutral of secondary side is earthedAnswerAn isolation transformer is a 1:1 ratio transformer; its function is to electrically isolate the secondary side from the primary side without changing the voltage. An example of an isolation transformer is the one used in a shaver socket.A distribution transformer is a step-down transformer, used within the electricity network's distribution system. An example of distribution transformer is a pole-mounted transformer, supplying low voltage to residences.(Of course, all mutual transformers provide electrical isolation between primary and secondary.)
the auto transformer is the one winding transformer. it ismaily used in practical purpose.
A transmission transformer steps the voltage up to a very high value so electricity can travel long distances on transmission lines from the power plant to a city or area with low loss. A distribution transformer steps the high voltage back down to a level that can be used for local distribution and use by businesses and homes.
yes we can place auto transformer in place of original transformer
A '33-kV transformer' is a three-phase primary-distribution transformer, used in the UK's electricity system to step down the 33-kV primary-distribution voltage to the 11-kV secondary-distribution voltage -the lowest voltage used in the high-voltage distribution system. These transformers are categorised as 'power transformers', and are located in what are termed 'primary substations'.
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