Download AVOP-ELEKTRO-MEL-005

Tutorial: Mechanic - electrician
Topic: Technical training
II. class
Passive components – transformers
Prepared by: Melichařík Lubomír
Projekt Anglicky v odborných předmětech, CZ.1.07/1.3.09/04.0002
je spolufinancován Evropským sociálním fondem a státním rozpočtem České republiky.
Transformer
Is a non-rotating electric machine
-allows you to transfer electrical energy
from one circuit to another through
mutual electromagnetic induction
-used mostly to convert AC voltage
(e.g. from low voltage to high), or for
galvanic isolation circuits.
Electrotechnical schematic symbols
Schematic symbol for a transformer
with an air core

Schematic symbol for a transformer
with a magnetic core

Schematic symbol for a transformer
with a ferrite core

Schematic symbol for a transformer
with a tap


Electrotechnical schematic symbols
Schematic symbol for a transformer
with multiple windings

Schematic symbol for a single-phase
transformer







The transformer is an AC converter
-it consists of three main parts: the coil, the magnetic circuit,
the insulation system.
-primary winding is used to convert electrical energy into
magnetic. Passing a current creates a magnetic flux Φ [Fí].
-this flux is guided in the magnetic circuit (core) to the
secondary coil.
-in the secondary coil according to the principle of Faraday’s
law of induction a voltage is induced
-therefore, the transformer works only on alternating or
pulsating current because the DC does not change the
magnetic flux (i.e. constant flux derivative is zero) and the
secondary winding no longer has a voltage.




-winding of small transformers are made of painted (enameled) wires of
various diameters
-the coil is wound onto the coil body (skeleton) thread after thread
-single-layer winding is interspersed with insulation. The surface of the coil
is insulated with cardboard or linen. It impregnates the vacuum pressure
impregnation
-voltage control taps on the second winding






Autotransformers
-are transformers, whose primary and secondary winding use the
same coil
-from a mechanical point of view, the coil is on an iron core, with
taps for the primary and secondary voltages
-a disadvantage is, that when we come to construct a galvanic
isolation of primary and secondary voltages
-a secondary winding tap can be realised by moving the slider
-used in electrical laboratories and in traction drive rail vehicles
 Draw
the schematic symbol for
a transformer.
 Draw
and explain the principle
of an autotransformer

















Divide the
According
According
According
According
-
transformers
to the number of phases
to the design of the magnetic circuit
to the uses
to the number of windings


Václav Malina
Adrian Schommers
Poznáváme elektroniku I.
Elektronika tajemství zbavená.
ISBN 3-92608-32-5