Table of contents | |
Introduction | |
Important Tasks Performed by Transformers | |
Transformer Construction | |
Ideal Transformer | |
Lenz's Law |
There are two general types of transformers, the core, type, and the shell type, which differ from each other by the manner in which the windings are wound around the magnetic cores.
In this type of transformer, the L.V. and H.V. windings are wound over the central limb and are inter-leaved or sandwiched. It performs better for low voltage, low power levels, whereas core type construction is used for high voltage, high power transformers.
Remember:
- Lower power transformers are air-cooled whereas large power transformers are immersed in oil for better cooling.
- The magnetic core is a stack of thin silicon-steel laminations about 0.35mm thick for 50 Hz transformers.
- In order to reduce the eddy current losses, these laminations are insulated from one another by thin layers of varnish.
- For reducing the core losses, transformers have their magnetic core made from cold-rolled grain-oriented sheet steel (CRGO). This material when magnetized in the rolling direction has low core loss and high permeability.
An ideal transformer possesses certain essential features.
The direction of induced emf is such that if it allows to cause a current then the current so produced, oppose the cause.
∴
or
e1 = E1max Sin(ωt + 900)
Note:
As we have assumed infinite permeability core this means zero magnetizing current is required for stabilizing the core flux.
23 videos|89 docs|42 tests
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1. What are the important tasks performed by transformers? |
2. How are transformers constructed? |
3. What is an ideal transformer? |
4. What is Lenz's Law and how does it relate to transformers? |
5. How do transformers help in reducing energy losses in power transmission? |
23 videos|89 docs|42 tests
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