STUDY OF SIGNALLING RELAYS WITH A VIEW OF OBTAINING THE LONGEST LIFE IN SERVICE HAVING REGARD TO THEIR PHYSICAL DIMENSIONS

In this report an account is given of the tests, their results and interpretation; these tests were deemed necessary by the A31 Specialists Committee in order to complete the task with which it had been entrusted, viz. the compilation of a statement on the measures required to increase the duration of life or to reduce the dimensions of a safety relay. Test results, the findings obtained by the Specialists and other data are compared with each other and the essential conditions are laid down which have to be met by the constructional elements of a safety relay, in order to ensure the operational security of the relays. These essential points were summed up in the "Conditions for safety relays" (both for proved and non-proved relays). While taking these conditions as a basis, the questions involved by the task to be completed (increased duration of life or reduction in the dimensions of a safety relay) can be answered as follows: 1. If a type of relay meets the minimum requirements contained in the above "Conditions for safety relays", it also meets the requirement pertaining to the minimum duration of life considered to be feasible in an economic respect (for defined contact loads: 2.10 to 6th power switching operations, equivalent to an average duration of life of 20 years) without entailing additional manufacturing costs. 2. The reduction in the dimensions of the relay is set limited by: (a) the conditions bearing on contact gaps and contact pressure, (b) the minimum distances between "live" components of the contact and its connections considered necessary for the sake of safety, (c) the power input of the coil. However, these possible minimum dimensions cannot be realized, amongst other factors, because of: (a) the use made of the relays (e.g. for section block installations) (b) the cross sections of the cable conductors, and (c) switching principles. The advantages and disadvantages resulting from the reduction in the dimensions of the relays are briefly mentioned in the report.

• Supplemental Notes:
  • Restrictions on the use of this document are contained in the explanatory material.
• Corporate Authors:

  International Union of Railways

  Office of Research and Experiments
  Utrecht,   Netherlands 
• Publication Date: 1962-10

Media Info

• Pagination: 110 p.

Subject/Index Terms

• TRT Terms: Direct current; Relays (Electricity); Reliability; Safety; Service life; Signaling; Tests
• Old TRIS Terms: Direct current relays; Question a31; Relays
• Subject Areas: Design; Railroads; Safety and Human Factors;

Filing Info

• Accession Number: 00052803
• Record Type: Publication
• Source Agency: International Union of Railways
• Report/Paper Numbers: A31/RF/E Final Rpt.
• Files: TRIS
• Created Date: Jul 8 1994 12:00AM