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Introduction
Unistar medium voltage All Polypropylene
capacitors are proven products of Universal Cables Ltd.
Low operating stresses, lower temperature rise and
losses make them superior to any other type of
capacitors. Absence of paper reduces the chances of gas
formation, bulging and bursting. This makes All PP
capacitors almost fire proof. These capacitors are best
suited for systems which have high and frequent voltage
fluctuations and harmonics caused on account of diodes,
thyristors and other non-linear loads. Seperate
aluminium foil used as electrode, enhances it;'s
capacity to withstand high inrush current, associated
with parallel switching, likes of which we come across
in automatic power factor correction schemes. That is
why in industrial applications All PP capacitors are
fast replacing Mixed Dielectric and other types of
capacitors. |
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Technology
UCL has been making All PP capacitors as
per the technology provided by General Electric Co. of
U.S.A. So far, these capacitors were made in high
voltage range. Now Universal Cables Limited has extended
this technology to medium voltage range. Further
improvements have been achieved by introducing extended
foil design which gives firm internal connection, lower
internal resistance and inductance, and high inrush
current withstanding capabilities. All the
sophistication and care required for high voltage
capacitors gets passed on to these capacitors as well,
which makes them the most superior capacitors in the
medium voltage range.
Manufacturing Process
Unistar All PP dielectric capacitors
consists of number of basic elements which are
constructed by winding layers of aluminium foil,
interleaved by bi-axially oriented polypropylene film.
Internal fuses are provided with each element. The
winding is carried out in an air conditioned room
equipped with special filters to provide dust- free
atmosphere, which is very vital for capacitors. Elements
thus formed are connected in parallel and then in delta.
the complete pack is inserted in a steel case and 3
terminals are brought out through suitable bushings.
Capacitors are put under vacuum drying and then
impregnated with non-PCB non-toxic oil. After removing
from the vacuum tank, units are sealed and then sent for
routine electrical testing, painting and assembly.
Periodically, few units are taken out from manufacturing
process and are subjected to rigorious type testts to
ensure quality standards.
Accessories
Capacitor Units are provided with terminal cover to
enclose live parts. Entry hole is provided for the
bottom entry of the cable. In case of banks, base
channel to mount the capacitors, common terminal cover
and a set of aluminium busbars are provided. Cable
glands are provided on request. |
Unistar PP Type Power Capacitors 