Page 11 - EngineerIT October 2021

FRONT COVER STORY

ArmCoil’s dry type transformer offerings have numerous IP ratings and enclosure
types available to suit every environment and application, be they in a dusty mine or up
in a skyscraper. Cast resin type transformers are encapsulated in a resin composition
which is fire and dust resistant. Durable and good quality ventilation devices are
fitted to increase cooling, as and when required. Maintenance is almost a
non-requirement on dry type and cast resin type transformers which have
an absolute minimal impact on the environment. The entire product can
be monitored through digital monitoring and Wi-Fi devices, as on the oil
cooled types.

Not one size fits all
As transformers age due to power surges, over demand or simply
having grown too small for the capacity required, the problem of finding
a suitable replacement that can deliver a higher capacity, is better
protected yet has to fit into the same space of the old transformer, is
not generally available off the shelf. “It is here where our more than
ten years of design and manufacturing experience comes to the
fore. Our engineers can, in most cases, design a transformer using
the latest technology that will fit into the available space, yet meet
increased delivery capacity still occupying the same space as the
old transformer. Designs can be adapted to facilitate assembling
the transformer on site in instances where access to the substation
or the medium voltage substation is restricted.

Meeting the solar challenges
With the new regulation of allowing systems of up to a 100 megawatt to be built by
independent power producers, many of these plants will be using string inverters distribution chain. “I believe we are such a
to convert the DC output from an array of panels to AC, requiring medium voltage company. I would welcome an opportunity
substations with low maintenance, high-capacity output transformers. “Our Armcoil to share our experience with you.
design team offers innovative solutions to meet both the electrical as well the physical Email me at MorneB@armcoil.co.za or
specifications”, Bosch said. call me on +27 11 763 2351. n

Standard vs high performance transformer For more information visit
Dry-type transformers, for a variety of reasons, have largely replaced oil-filled units within www.armcoil.co.za
industrial, commercial and institutional buildings. However, unlike oil-filled units in the utility
grid, little attention is paid to the energy efficiency of dry-type units. Unlike motors, they
have no moving parts to wear out, and so are expected to last 20 years or more. ArmCoil is an ISO accredited manufacturing,
Efficiency is seldom specified when buying dry-type transformers. Values of 95% or repair and on-site maintenance facility
higher are typical, and differences between high- and low-efficiency units are only 1% to located west of Johannesburg, in the
2%, with a significant first-cost premium for the more efficient units. industrial area of Roodepoort. The
But first cost is not the last cost of any transformer. Complete life-cycle costs must be ARMCOIL facility boasts a fully equipped
carefully examined along with the economics of high-efficiency, dry-type transformers. factory for transformer, miniature and MV
substation manufacturing - from design stage
Life cycle costing to testing, delivery and installation. ArmCoil
According to the Copper Association, when a lower cost, 98% efficient unit and a higher holds three ISO accreditations, namely
cost unit at 99% are compared, it means that the losses are cut in half. 9001:2015, 45001:2018 & 14001:2015,
Conductor losses, also known as coil losses or load losses, should not be overlooked assisting the company and being conscious
– because such losses vary by the square of the load. That means a fully loaded of the wellbeing of its employees and clients.
transformer has four times the load losses compared with one running at 50% of its design ArmCoil is an environmentally
load. In many applications, transformers are heavily loaded. But even at lower load factors, responsible company that is committed to
if the units are not efficient (and many are not), losses mount rapidly. noise and pollution reduction by strictly
Thus, the continuing costs of transformer losses should be balanced with the savings following the stipulated regulations to
to be gained from efficient units – savings which go on year after year – quickly paying minimise environmental impact in its
back the extra first cost. working areas, community and products
Other benefits pile up as well. Efficient transformers run cooler and thus more reliably, installed at various sites across South Africa.
because of decreased stress on insulation materials. As a result, they will have a higher Extensive quality procedures have been
overload capacity, an important issue in dry-type transformers. The ultimate result can be developed and continually aligned with
units with a smaller kVA rating doing the same job, with attendant first-cost savings. ArmCoil’s quality 9001:215 management
As Bosch said in his introduction, it ultimately all boils down to having a well-developed system. n
and strong local transformer manufacturing industry to meet the country’s needs in the

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