Page 8 - Industrial Technology EXTRA 8th June 2020

could have been avoided through careful planning.
This is why, in addition to its bespoke resistor
capabilities, Cressall has produced the EV2 range of
advanced modular water-cooled resistors. Able to
operate as a single module, or a combined unit, the
EV2’s 25kW continuous rating means when
multiple units are combined in an enclosure, power
input can range to over 1MW, while remaining
space-efficient and using the existing ships
to the current squared, multiplied by resistance. As freshwater cooling system to cool the resistor.
the power rating is measured and defined at Choosing the correct resistor is essential to ensure
standard conditions and is extremely dependent productivity is as high as possible, by meeting the
upon the final operating conditions, changes should specific requirements of the project alongside
be expected when used in the marine sector. demands of the ship.
Therefore, it may be wise to install a resistor with a
power rating in excess of what is expected. Size and weight
Cressall has the expertise and facilities to produce
Making the selection bespoke resistors, specifically designed to meet
Choosing a resistor that meets the required power electrical needs while fitting into tight areas, as is
and resistance rating is essential. If the power often needed on board ships with limited space.
current passed through the resistor exceeds its Space is often particularly restricted in machine and
rating at any given time, both the resistor and engine rooms, where resistors are usually installed,
connected machinery could become damaged, because they are tightly packed with equipment.
which could be very costly and impact other This means small off-the-shelf resistor solutions are
associated systems. often installed.
Resistors with an insufficient power rating may For some situations, such as braking resistors
become overloaded, carrying a risk of fire. Although used on thrusters, a small compact resistor with a
resistor designs use non-flammable materials, the comparatively low power rating is the perfect fit.
high temperatures could cause problems with For the industry to continue to prosper, it is
adjacent components, which is extremely important that we take actions to help make ships
dangerous on ships. and marine vessels as productive and efficient as
In addition to damaging the ship structure, the possible. Although some may see a resistor as just
confined space makes it immediately dangerous for another component in electronic equipment, they
workers and equipment on board the vessel. This are an essential way of making the most of
does mean that resistors that are correctly sized otherwise wasted energy.
with higher power ratings are typically more Choosing which resistor to install from the wide
expensive, so the cost of the resistor is higher. range available is essential to ensure productivity is
These costs can quickly add up, for example as high as possible, by meeting the specific
when six to eight braking resistors are employed on requirements of the project alongside demands of
thrusters. Installing a resistor with an excessive the ship.
power rating may be an unnecessary cost, which www.cressall.com

June 2020 • INDUSTRIAL TECHNOLOGY EXTRA! • p8