Powering Freight & Transportation - Power Systems Design

14
Energy-Efficient Chokes
for Transportation
SMP Sintermetalle Prometheus
GmbH & Co KG, manufacturers
of inductive components and
magnetically soft materials, cores and
mouldings is based in Graben-Neudorf
near Karlsruhe, Germany and has introduced
a range of chokes designed
specifically for use with inverters. The
special feature of these units is their
ingress protection class of IP66, which
makes them suitable for use in tough
environments as found in rail transportation,
to restrict incoming current on the
line side.
Because of the high degree of protection,
these chokes can be fitted outside
the inverters, so the heat generated by
the choke is not discharged inside the
inverter. This results in a lower internal
inverter temperature, which removes
the need for cooling fans, saving both
energy and installation space. Placing
the choke outside the inverter has
the further advantage of reducing the
inverter’s overall dimensions, which
further cuts space and energy demand.
For the choke itself, external mounting
has the benefit of allowing it to be designed
for lower ambient temperatures.
While inverters, for example in railway
applications, can have an internal
temperature of 70 to 80°C, the outside
temperature to which underfloor-mounted
electronics are exposed is unlikely to
exceed about 40°C. SMP has developed
chokes for external mounting even
for use on offshore oil platforms. Their
special protective paint coating protects
these components from direct sunlight,
sea water, rain and corrosive gasses.
To simplify mounting outside the
inverters, SMP provides the chokes with
special mounting fixtures. The choke
and the mounting plate are fitted on the
device’s outside and the connecting
cables pass through a sealed opening.
SMP choke for railway applications.
To meet demanding requirements in
power electronics, SMP has developed
high-performance chokes and filters.
These inductive components offer a high
energy storage capacity at low volume,
reduced losses, good EMC characteristics
and a cost-conscious design.
Depending on their application, they are
constructed either as single-conductor
chokes for high-current applications,
individual chokes, choke modules or LC
filters.
For wider applications in power electronics,
power generation, instrumentation
and control, SMP supplies chokes
and filters for frequencies up to 200kHz
and current ratings up to 1000 amperes,
with component sizes ranging from 36
to 300mm diameter and weights from
50g to 130kg. The components can
be used in a temperature range up to
180°C. They are easy to fit and, with
numerous mounting options, can be
mounted according to the available
space. To allow for a wide range of requirements,
components can be made
to all common standards, including protection
type IP20 and IP65. All products
are RoHS- and WEEE-conformant and
the materials used are UL-listed.
www.smp.de
Power Systems Design October 2008