3. INTRODUCTION
• A transformer is a static device. The
word 'transformer' comes form the
word 'transform’.
• Transformer is not an energy
conversion device, but it is device
that changes electrical power at one
voltage level into electrical power at
another voltage level through the
action of magnetic field but with a
proportional increase or decrease in
the current ratings., without a
change in frequency.
• It can be either to step-
up or step down.
6. STEP UP
TRANSFORMER:
• A transformer in which voltage
across secondary is greater than
primary voltage is called a step-up
transformer (shown in figure).
• In this type of transformer, Number
of turns in secondary coil is greater
than that in Primary coil, so this
creates greater voltage across
secondary coil to get more output
voltage than given
through primary coil.
7. • A transformer in which voltage
across secondary is lesser than
primary voltage is called a step-
down transformer (shown in figure)
• In this type of transformer, Number
of turns in secondary coil is lesser
than that in Primary coil, so this
creates lesser voltage across
secondary coil, so we get low output
voltage than given
through primary coil.
STEP DOWN
TRANSFORMER:
8. WORKING PRINCIPLE
• The transformer works on the principle
of Faraday’s law of electromagnetic
induction and mutual induction.
“According to Faraday’s rule of
electromagnetic induction, this alternating
flux links the transformer primary and
secondary windings magnetically and
generates EMFs E1 in the primary winding
and E2 in the secondary winding. The
(E1) is referred to as the primary EMF,
while the EMF (E2) is the secondary
------(i) ------(ii)
Dividing (i) and (ii),
9. • There are usually two coils – primary coil and
secondary coil – on the transformer core. The
core laminations are joined in the form of strips.
The two coils have high mutual inductance.
When an alternating current passes through the
primary coil, it creates a varying magnetic flux.
As per Faraday’s law of electromagnetic
induction, this change in magnetic flux induces
an EMF (electromotive force) in the secondary
coil, which is linked to the core having a
primary coil. This is mutual induction.
• Overall, a transformer carries out the following
operations:
1.Transfer of electrical energy from one circuit to
another
2.Transfer of electrical power through
electromagnetic induction
3.Electric power transfer without any change in
frequency
4.Two circuits are linked with mutual induction
12. SINGLE-PHASE
TRANSFORMER
• A type of transformer which consists of
only one pair of the transformer coils or
windings, i.e., one primary winding and
one secondary winding, and is used for
transforming the single-phase alternating
voltage to the desired value, is known
as single-phase transformer.
• The single-phase transformers are
commonly used in different applications
such as for supplying electric power to
domestic loads in rural areas where the
demand and cost is less.
13. THREE-PHASE
TRANSFORMER
• A transformer which consists of three-
pairs of transformer windings placed in a
three-section iron core, where each
section contains a pair of a primary
winding and a secondary winding and is
used to step-up or step-down the three-
phase alternating voltage is known as a
three-phase transformer.
• The three-phase transformers are widely
used in electric power system for
transmission and distribution of electric
power. As a single 3-phase transformer
can supply three single-phase circuits,
hence it is economical than a single-
phase transformer.
15. CORE TYPE
TRANSFORMER
• In the core type transformer, the
magnetic circuit of the transformer
consists of two sections namely two
vertical section called limbs and two
horizontal sections called yokes. The
half of each winding (primary and
secondary windings) is placed on each
limb of the core, so that the leakage flux
can be minimized.
• The major advantage of a core type
transformer is that it is easier to
dismantle for repair and maintenance.
• The core type transformers are mainly
used in high voltage applications such as
distribution and power transformers.
16. SHELL TYPE
TRANSFORMER
• In the core type transformer, the
magnetic circuit of the transformer
consists of two sections namely two
vertical section called limbs and two
horizontal sections called yokes. The
half of each winding (primary and
secondary windings) is placed on each
limb of the core, so that the leakage flux
can be minimized.
• The major advantage of a core type
transformer is that it is easier to
dismantle for repair and maintenance.
• The core type transformers are mainly
used in high voltage applications such as
distribution and power transformers.
18. 1. SELF-COOLEDTRANSFORMERS:
• Self-cooled transformers are designed to dissipate heat generated during operation
through natural convection. They rely on the surrounding air for cooling without the use
of any additional cooling medium such as oil or fans.
• These transformers typically have a corrugated or finned exterior surface to increase the
heat dissipation area and promote airflow.
2. AIR-COOLEDTRANSFORMERS:
• Air-cooled transformers, as the name suggests, use air as the primary cooling medium.
They employ fans or blowers to increase the airflow and enhance heat dissipation. The
fans can be mounted on the transformer itself or placed separately in the cooling system.
• Air-cooled transformers are often used in applications where the ambient temperature is
relatively low, and the heat dissipation requirements are moderate.
19. 3. OIL-COOLEDTRANSFORMERS:
• Oil-cooled transformers use a dielectric oil as the cooling and insulating medium. The oil
circulates within the transformer, carrying away heat generated by the core and windings.
• The oil transfers the heat to the transformer tank, which provides a larger surface area for
heat dissipation into the surrounding air. The tank is often equipped with cooling fins or
radiators to increase the cooling efficiency. In some cases, oil-cooled transformers also
incorporate fans or pumps to enhance the circulation of oil and improve cooling.
• Oil-cooled transformers are commonly used in applications where high-power levels or
continuous operation demand efficient heat dissipation. They are particularly suitable for
locations with high ambient temperatures or environments with heavy electrical loads.
21. 1. CORELOSSES:
Core losses occur in the transformer's magnetic core and are primarily caused by two
factors: hysteresis and eddy currents.
• Hysteresis Loss: Hysteresis loss occurs due to the reversal of magnetization in the
transformer core with each alternating current (AC) cycle. This loss is caused by energy
dissipation within the core material and is dependent on the magnetic properties of the
core material.
• Eddy Current Loss: Eddy currents are induced within the laminated core of the
transformer due to the changing magnetic field. These currents circulate within the core
and cause power loss due to resistive heating. Eddy current losses can be reduced by
using laminated or insulated core materials.
22. 2. COPPERLOSSES:
• Copper losses, also known as I²R losses, occur due to the resistance of the transformer's
winding conductors.
• When current flows through the windings, it encounters resistance, resulting in power loss
in the form of heat.
• Copper losses can be further divided into two components:
a. Winding Resistance Loss: This loss occurs in the primary and secondary
windings of the transformer.
b. Leakage Reactance Loss: This loss is caused by the leakage reactance, which is
the magnetic field generated by the winding current not perfectly linking with
the adjacent windings.
23. 3. STRAYLOSSES:
• Stray losses in transformers refer to the energy losses that occur due to various factors
other than the intended energy transfer between the primary and secondary windings.
These losses include leakage flux losses.
• Transformers rely on magnetic fields to transfer energy between windings. However, not
all of the magnetic flux generated by the primary winding effectively links with the
secondary winding.
• Some portion of the magnetic flux "leaks" or passes through the air or surrounding
structures, resulting in leakage flux losses.
• Leakage flux losses increase with higher operating currents and frequencies, as well as
with larger air gaps between the windings.
24. 4. DIELECTRICLOSSES:
• Dielectric losses occur in the insulating materials used within the transformer, such as
between windings and between windings and the core.
• Insulating materials have dielectric properties that cause energy dissipation in the form of
heat due to the formation of capacitance.
• When an alternating voltage is applied across insulating materials, the capacitance
between conductive elements results in the flow of displacement currents, causing energy
losses.
• Dielectric losses depend on the quality and properties of the insulation materials used in
the transformer.
25. TRANSFORMER
EFFICIENCY
• Transformers form the most
important link between supply
systems and load. Transformer’s
efficiency directly affects its
performance and aging.
• The Efficiency of the transformer is
defined as the ratio of useful output
power to the input power. The input
and output power are measured in
the same unit. Its unit is either in
Watts (W) or KW. Transformer
efficiency is denoted by Ƞ.
where,
•V2 – Secondary terminal voltage
•I2 – Full load secondary current
•Cosϕ2 – power factor of the load
•Pi – Iron losses = hysteresis losses + eddy current losses
•Pc – Full load copper losses = I2
2Res
26. APPLICATIONS AND
USES OF
TRANSFORMERS
• Power generation: Transformers are used in
power plants to increase the voltage of the
electricity generated by the plant before it is sent
to the grid.
• Transmission and distribution: Transformers
are used in the transmission and distribution of
electricity to increase or decrease the voltage of
electricity as it is sent from power plants to
homes and businesses.
• Lighting: Transformers are used in lighting
systems to decrease the voltage of electricity
before it is sent to light bulbs.
• Audio systems: Transformers are used in audio
systems to increase or decrease the voltage of
electricity before it is sent to speakers.
• Electronic equipment: Transformers are used in
a variety of electronic devices, including
computers, TVs, radios, and cell phones.
27. CONCLUSION:
• In conclusion, transformers are vital components in electrical systems, playing a crucial role in
power generation, transmission, distribution, and various other applications. They facilitate
efficient energy transfer by stepping up or stepping down voltage levels as needed. By utilizing
the principles of electromagnetic induction, transformers enable the transmission of electrical
energy over long distances while minimizing power losses.
• Transformers come in different types, such as power transformers, distribution transformers,
and instrument transformers, each designed for specific applications. They consist of core,
windings, and insulation, and their efficiency is influenced by factors like core losses, copper
losses, and stray losses.
• Efficiency is a significant consideration in transformer design, as it impacts energy
consumption, operating costs, and environmental sustainability. Manufacturers continuously
work towards optimizing transformer designs to minimize losses and enhance overall
efficiency.
• Transformers find applications in power generation plants, electrical power transmission and
distribution networks, industrial settings, renewable energy systems, railways, transportation,
and electronic devices. Their versatility and adaptability make them indispensable in modern
electrical infrastructure.
• Understanding the functioning, types, and applications of transformers is crucial for engineers,
technicians, and individuals working with electrical systems. By utilizing transformers
effectively, we can ensure efficient energy utilization, reliable power supply, and sustainable
electricity infrastructure.
