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Post by brigham on Apr 27, 2017 7:27:32 GMT
I thought they would have had current detection to pick up blown lamps. There will almost certainly be a 'lamp out' detector of some sort. The 'back-up' lamp is to keep the signal lit until the main lamp is changed. I hadn't realised that signal lamps were run on AC. Is that the 33 1/3-cycles supply? |
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DWS
every second count's
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Post by DWS on Apr 27, 2017 8:12:15 GMT
I thought they would have had current detection to pick up blown lamps. There will almost certainly be a 'lamp out' detector of some sort. The 'back-up' lamp is to keep the signal lit until the main lamp is changed. I hadn't realised that signal lamps were run on AC. Is that the 33 1/3-cycles supply? I may be wrong but I think that 33 1/3 is no longer used for signal lighting . |
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Deleted
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Post by Deleted on Apr 27, 2017 9:30:03 GMT
I thought they would have had current detection to pick up blown lamps. That is only on NR signals it's known as a lamp proving unit |
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Deleted
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Post by Deleted on Apr 27, 2017 9:31:05 GMT
There will almost certainly be a 'lamp out' detector of some sort. The 'back-up' lamp is to keep the signal lit until the main lamp is changed. I hadn't realised that signal lamps were run on AC. Is that the 33 1/3-cycles supply? I may be wrong but I think that 33 1/3 is no longer used for signal lighting . 33 1/3hz is still used its no longer used as the feed for track circuits on SSL |
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DWS
every second count's
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Post by DWS on Apr 27, 2017 19:43:41 GMT
I may be wrong but I think that 33 1/3 is no longer used for signal lighting . 33 1/3hz is still used its no longer used as the feed for track circuits on SSL So what is it used for ? |
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Post by Deleted on Apr 27, 2017 19:54:27 GMT
Everything else which has nothing to do with track circuits
33 1/3hz was considered to interfere with the S stock traction system, before the S stock was cleared to run everywhere track circuits were changed to either 125hz but they soon ran out of relays. Completely changed to either Westinghouse FS2550 or Bombardier Ebi200 otherwise known as Ti21.
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Post by principlesdesigner on Aug 4, 2017 14:14:48 GMT
Everything else which has nothing to do with track circuits 33 1/3hz was considered to interfere with the S stock traction system, before the S stock was cleared to run everywhere track circuits were changed to either 125hz but they soon ran out of relays. Completely changed to either Westinghouse FS2550 or Bombardier Ebi200 otherwise known as Ti21. Other way round - S Stock traction package generates frequencies in the 33 1/3 Hz range, so could falsely energise the track relay |
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