Advantages of Thyristor Locomotives and Experience in Sweden

The Swedish State Railways´ decision to order thyristor -controlled locomotives has given Allmÿnna Svenska Elektriska Aktiebolaget (ASEA) the privilege of being the first company in the world to build this type of locomotive in a long series. This paper explains the choice of low-frequency ac for electric traction equipment in Sweden and then traces the development of the modern thyristor locomotive. Advantages of this design, and special measures required to deal with reactive power and harmonic currents, are set forth, as are the operating experience and tests which have been conducted on this new type of locomotive.