14
4.7
MAJOR COMPONENT
4.7.1
VARIAC
Variac is also known as Dimmer, Autotransformer or Variable transformer
It is normally round in the shape. Silicon CRGO toroidal core is used for the base & copper wire
with specific turn ratio according to the capacity is used. The basic purpose of dimmer is to
increase or decrease the voltage which is fed to the buck boost transformer. 50% of the output
voltage
is
increased
or
decreased
by
dimmer
only.
Let us take an example: If the input voltage is 160V, the dimmer will increase it to 190V & rest
of the 30V (since 220V is required to run any single phase load) will be done by Buck Boost
Transformer.
4.7.2
BUCK BOOST TRANSFORMER
Contrary to dimmer it is in rectangular shape. Bobbin is fitted with EI CRGO or HRGO core.
When the transformer structure is built, it is dipped in varnish tank for extra protection.
This type of Insulating varnish also called transformer varnish is put on all the windings used
in buck boost transformers to encapsulate them before the servo stabilizer is ready for regress
testing. Transformer varnish enhances coil life and protects windings in the transformer from
environmental exposure that would otherwise get damaged due to vibrations. This varnish
can be used as a great insulator for any coil of wire. Though trans former is there in Isolation
Transformer also, But it different from buck boost transformer
