El Chopper: un nuevo sistema de control de c.c. y su aplicación a la tracción ferroviaria

• Autores: Miguel Ángel Munárriz Casajus
• Localización: Revista A.I.T., ISSN 0378-3294, Nº. 16, 1977, págs. 51-62
• Idioma: español
• Títulos paralelos:
  • The chopper: a new control system for D.C. Motors and its application to railway haulage
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• Resumen

  • The role played by the Chopper can be compared with that of a direct current transformer. That is, it transforms a constant direct current (the current from the catenary) into a direct current, too, but the amplitude of which can be changed at will.

    The basic component of the Chopper creates some current harmonics which must be eliminated; to obtain that, an inlet filter is interlaid.

    The study of the quenching circuit and corresponding curves is carried out on the following two assumptions: the first one is that the intensity is constant; while the second one is that the voltage does not change.

    The Chopper is also used for the braking operation, which is like the hauling one. This system does not dissipate current, it recuperates it. A mixed braking can be also carried out, that is a combination of the Chopper and rheostatic braking systems (the last system dissipates energy and is used as an auxiliary system of the first one).

    The Chopper is also used for "control equipment" and its roles are:

    - Operation, haulage and braking, control, with intensity and voltage regulators.

    - Auxiliary tiristor ignition signal phasing out devices.

    - Amplifiers of the received signal.

    Among the advantages of using the Chopper, the following ones can be brought out: servicing decrease; energy saving; start resistance elimination; recuperation braking; adoption of new automation techniques; traction increase.

    On the other hand, among the disadvantages, the following ones should be pointed out: interferences and its short economic study, which makes it, at present, more expensive than conventional systems, but which, in the near future, will be cheaper than conventional ones.

    The development of the Chopper, which started in 1965, is being very important, having many applications which have been put to work with full efficiency on public transportation since 1970.