11-05-2013, 03:28 PM
PRESENTATION ON TRANSFORMER
TRANSFORMER.pptx (Size: 1.77 MB / Downloads: 41)
INTRODUCTION:-
TRANSFORMER: A static device-
Utilized for raising or lowering the voltages.
Transfers electrical energy from one circuit to other through inductive coupling.
No change in frequency of the supply.
Very efficient device.
CONSISTS OF :-
The a.c. supply, load.
Laminated magnetic core with insulation.
Two windings- i.e., the primary coil and the secondary coil windings.
WORKING OPERATION:
A varying current in the first or primary winding
creates a varying magnetic flux in the transfor-
-mer's core and thus a varying magnetic field
through the secondary winding. This varying
magnetic field induces a varying Electromot-
-ive force (EMF), or "voltage", in the secondary
winding. This effect is called inductive coupling.
Points:
Magnetizing current produced megnetomotive force magnetic flux.
Both self + mutual inductance takes place.
So, voltage energized or de-energized from one coil to other.
Purpose achieved.
Instead, some losses occur.
Efficiency decrease a bit but can be minimized.
APPLICATIONS:-
Before the development
of the transformer, electric
power distribution prima-
-rily used direct current.
It was difficult for a DC
Utility-power generation
station to be more than a
few kilometres from the user.
It was understood that high voltages allowed long distance transmission with low amperage (250 volts at 5000 amps = 25000 volts at 50 amps) so the transmission wires can be smaller and less expensive, but it still needed to be stepped back down to utility voltage at the customer's location.
So, transformers are used for efficient transmission.
Tesla Coil:-
High voltage discharges having an appearance similar to lightning can be obtained from a properly designed Tesla coil. The Tesla coil employs the principles of the transformer with a small number of turns on the primary and a large number of turns on the secondary.
The high frequency input to the primary coil is transformed up to about a million volts, and therefore the current is very small. The high voltage is enough to produce spectacular electric discharges like those shown above.