REO UK, specialist in high-quality power equipment, including electronic controllers, components and electrical regulators, has added purpose-wound components for the railway industry to its product range. As well as expanding the company's offering to electrical engineers in the UK, the new range also demonstrates REO's ability to provide specially engineered solutions for particular markets.
The products being introduced to the UK are from the Nieke division of REO Inductive components, which has had over 50 years of experience in designing and producing components for use with AC and DC converters employed in the railway industry, where reliability is a priority. There are three broad categories of components: chokes, transformers and inductor / filters.
For DC traction systems the company has developed harmonic filters, short-circuit current limiters, chopper reactors and line filters with unique designs that ensure good linearity of inductance with varying current and frequency. Often DC chokes are fitted to provide protection against short-circuits but they also filter out parasitic AC disturbances.
One particular choke, which is used for resonant filters on 15kV mains transformers that are fitted to European locomotives, has a novel air-core design and this is free of stray fields. Consequently, it is highly stable irrespective of frequency and has low losses even at very high frequencies.
Another important application for chokes is for limiting the dV / dt between the converter and motor with the purpose of extending motor life, reducing audible noise and to provide current smoothing. Other chokes are produced for reducing harmonics and also for providing smoothing on auxiliary converters, which provide power for buffet cars, air-conditioning equipment and passenger's lap-top computers.