The document discusses the transformer, including its basic principles, construction, and types. A transformer transfers electrical energy from one AC circuit to another by means of a changing magnetic field produced by an input current in its primary winding. This changing magnetic field induces a voltage in a secondary winding. The voltage can be increased or decreased depending on the relative number of turns in the primary and secondary windings. Transformers allow efficient transmission of power over long distances and stepping voltages up or down for use in homes and industry.

1. Persented by-vishal sahu
BPT=1semester
Jaipur national university
TRANSFORMER

2. Introduction
■ The transformer is a static device which is used to transfer electrical
energy from one ac circuit to another ac circuit.
■ Input to a transformer and output from a transformer both are
alternating quantities (AC).
■ Electrical energy is generated and transmitted at an extremely high
voltages. The voltage is to be then reduced to a lower value for its
domestic and industrial use.
■ This is done by using a transformer.

3. ■ The power transmission system using transformers is
shown in figure.
■ When the transformer changes the voltage level, it
changes the current level also.

4. Basic Principle

5. ■ The primary winding is connected to the single-phase ac
supply, an current starts flowing through it.
■ The ac primary current produces an alternating flux (Ф) in the core.
■ Most of this changing flux gets linked with the secondary winding
through the core.

6. ■ The varying flux will induce voltage into the secondary
winding according to the faraday’s laws of electromagnetic
induction.
■ Voltage level change but frequency i.e. time period remains
same.
■ There is no electrical contact between the two winding, an
electrical energy gets transferred from primary to the
secondary.

7. ■ A simple transformer consists of two electrical
conductors called the primary winding and the
secondary winding.
■ Energy is coupled between the windings by the
time varying magnetic flux that passes through(
links) both primary and secondary windings.

8. Construction
■ For the simple construction of a transformer, you must need two coils
having mutual inductance and a laminated steel core.
■ The two coils are insulated from each other and from the steel core.
■ The device will also need some suitable container for the assembled core
and windings, a medium with which the core and its windings from its
container can be insulated.

9. ■ In order to insulate and to bring out the terminals of the winding
from the tank, apt bushings that are made from either porcelain or
capacitor type must be used.
■ In all transformers that are used commercially, the core is made out
of transformer sheet steel laminations assembled to provide a
continuous magnetic path with minimum of air-gap included.

10. ■ The steel should have high permeability and low hysteresis
loss.
■ For this to happen, the steel should be made of high silicon
content and must also be heat treated.
■ By effectively laminating the core, the eddy-current losses
can be reduced.

11. ■ The lamination can be done with the help of a light coat of
core plate varnish or lay an oxide layer on the surface.
■ For a frequency of 50 Hertz, the thickness of the
lamination varies from 0.35mm to 0.5mm for a frequency
of 25 Hertz.

12. Types of transformer
■ 2 types
• 1. Core- Type Transformer
• 2. Shell-Type Transformer
■ 1.Core-type Transformer
• the windings are given to a considerable part of the core.
• The coils used for this transformer are form-wound and are
of cylindrical type.

13. • The general arrangement of the core-type transformer
with respect to the core is shown below.
• Both low-voltage (LV) and high voltage (HV) windings
are shown.
• The low voltage windings are placed nearer to the core
as it is the asiest to insulate.
• The effective core area of the transformer can be
reduced with the use of laminations and insulation.

14. ■ 2. Shell-Type Transformer
• In shell-type transformers, the core surrounds a considerable portion
of the . windings.
• The comparison is shown in the figure below.
• The coils are form-wound but are multi layer disc type usually wound
in the form of pancakes.
• Paper is used to insulate the different layers of the multi-layer discs.
• The whole winding consists of discs stacked with insulation spaces
between the coils.

15. ■ Applications of a transformer
■ Transformers are used in most electronic circuits. A transformer
has only 3 applications;
■ To step up voltage and current.
■ To Step down voltage and current
■ To prevent DC – transformers can pass only Alternating
Currents so they totally prevent DC from passing to the next
circuit.

16. Uses of transformer

17. ■ The most important uses and application of Transformer are:
■ It can rise or lower the level of level of Voltage or Current
( when voltage increases, current decreases and vice virsa
because P =V x I, and Power is same ) in an AC Circuit.
■ It can increase or decrease the value of capacitor, an inductor
or resistance in an AC circuit. It can thus act as an impedance
transferring device.
■ It can be used to prevent DC from passing from one circuit
to the other.
■ it can isolate two circuits electrically.

18. Article....
Faradic current
■ ABSTRACT
■ Here we report a facile approach to synthesize a novel nanostructured
thin film comprising Cu nanoparticles (NPs) and reduced graphene
oxide (rGO) on a glassy carbon electrode (GCE) via the direct
electrochemical reduction of a mixture of cupper and graphene oxide
(GO) precursors.
■ The effect of the applied potential on the electrochemical reduction of
CO2 was investigated using linear sweep voltammetric (LSV) and
chronoampero- metric (CA) techniques.
■ Carbon monoxide and formate were found as the main products based
on our GC and HPLC analysis.

19. Results and discussion
■ As seen from the FE-SEM images, a graphene-like thin film was
formed following the electrochemical reduction of graphene oxide
(Fig. 1a), while a crystal-like cluster structure of Cu NPs appeared
subsequent to the electrochemical reduction of the CuSO4
precursor (Fig. 1b).
■ The simultaneous formation of the Cu/rGO thin film was achieved
following the electrochemical reduction of the mixed GO and CuSO4
precursor (Fig. 1c), where Cu NPs with ~20 nm were uniformly
distributed on the rGO sheets.

20. Conclusions
■ A novel nanostructured Cu/rGO thin film was directly formed on the
GCE surface via a facile one-step electrochemical reduction of their
precursor mixture.
■ The SEM images showed that Cu nanoparticles were uniformly
distributed on the rGO nanosheets.
■ LSV and CA were em-ployed to study the effect of the applied
potential on the electro-chemical reduction of CO2 and to determine
the instant and the steady- state current efficiency of the Cu/rGO
thin film, demonstrating that the Cu/rGO thin film was highly
efficient for CO2 reduction.