Transformer Construction A single-phase transformer has two electrical coils as, again, the primary and secondary winding. The primary winding is where the power supply is connected, while the secondary winding is where electricity is induced.
The primary and secondary windings of a transformer can be connected in different configuration as shown to meet practically any requirement. In the case of three phase transformer windings, three forms of connection are possible: “star” (wye), “delta” (mesh) and “interconnected-star” (zig-zag).
Use. Distribution transformers are normally located at a service drop, where wires run from a utility pole or underground power lines to a customers premises. They are often used for the power supply of facilities outside settlements, such as isolated houses, farmyards or pumping stations at voltages below 30 kV.
The delta–wye connection is the most commonly used three-phase transformer connection. The wye-connected secondary allows single-phase load to be distributed among the three phases to neutral instead of being placed all on one winding as with a four-wire delta secondary.
If the primary of a transformer is connected to the DC supply, the primary will draw a steady current and hence produce a constant flux. Consequently, no back EMF will be produced. Care must be taken not to the connect the primary of a transformer across the DC Supply.
In normal operation, electricity flows into the transformer on the high-voltage side where it goes into a coil of wire, usually wound around an iron core. As the electricity flows through this coil, it creates a magnetic field that “induces” a voltage in the other coil. Each coil has a different number of turns.
The main disadvantage of an autotransformer is that it does not have the primary to secondary winding isolation of a conventional double wound transformer. Then an autotransformer can not safely be used for stepping down higher voltages to much lower voltages suitable for smaller loads.
As the two windings are connected in series, the same amount of current flows through each winding, then the secondary current is the same at 2.5 Amps. So for a series connected secondary, the output in our example above is rated at 24 Volts, 2.5 Amps. Consider the parallel connected transformer below.
Applications of Step Down TransformerIt is used in the main adapters and chargers for cell phones, CD players and stereos.It can be used to step down the voltage level in transmission line.In welding machines it is used in reducing voltage and increasing current.More items
Explanatory Answer: DC voltage applied to the primary of a transformer sets up a constant magnetic flux in its core. This high current causes huge heat loss, causing the transformer core to burn and hence, DC power is never applied to transformer.
In direct current supply, the change in frequency with respect to time is null, which means the dc supply cant produce a dynamic magnetic field; hence mutual induction cant possible on direct current supply since the primary winding of the transformer has a very low value of resistance so it cant oppose the