page_title: FS Class E.550
section_title: Description
hierarchical_section_title: FS Class E.550 / Description
caption_attribution_description: English: Design of the power transmission of italian electric triphase locomotives FS E.554 Italiano: Disegno di trasmissione del moto a biella articolata delle locomotive elettriche italiane FS E.554
context_page_description: The FS Class E.550 was a class of three-phase electric locomotive used in Italy, introduced in the 20th century, which remained in service until 1965.
context_section_description: E.550 had five axles connected to the two electric motors through an articulated coupling rod. The three center axles were rigidly mounted to the frame and the center axle's wheels were without flanges.  The outer axles were mounted in a manner that allowed them to turn into curves.  The wheels were small, and thus adapted to heavy freight or slow passenger services at low speed. The locomotive had two cabs, one at each end of the central compartment. The motors were asynchronous three-phase, which could be connected in series at low speed and in parallel at higher speeds. The connections were enabled through a tambour connector using a liquid-cooled rheostat. Feeding was provided by paired trolley poles at each end, each pair carrying two bow collectors for the two wires of the three phase system.
  Braking was provided by an automatic continuous brake and a regulated, hand-operated brake.
caption: Diagram of triangle drive on Class E.554
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