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Post by paterson00 on Mar 1, 2010 23:20:13 GMT
I have assisted testing a few of these and would like to know more about them. I'd also like to get an explination of the dead section of two adjacent tracks and how the definition if each track circuit is created
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mrfs42
71E25683904T 172E6538094T
Big Hair Day
Posts: 5,922
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Post by mrfs42 on Mar 2, 2010 13:07:03 GMT
I'd also like to get an explination of the dead section of two adjacent tracks and how the definition if each track circuit is created Each JTC is created by an area of a given frequency - the boundaries of the dead section are created by track bonds, and no current will flow between the bonds. I think the 'dead section' (where an axle might not be picked up) is about 4 - 4½m either side of the dead section track bonds, max. length 9m. Please excuse the rather scrappy diagram, as it is drawn from memory: AIUI In the green and purple areas, this is the area where an axle might not (green) and definately not (purple) drop the track circuit. I have a vague feeling that the minimum drop shunt for a single axle is 0.3 ω ie about a third-of-an-ohm. HTH.
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Tom
Administrator
Signalfel?
Posts: 4,196
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Post by Tom on Mar 6, 2010 18:04:03 GMT
And to follow on, the test shunt value used is 0.5 ohm.
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Post by paterson00 on Jul 15, 2010 3:44:40 GMT
I'd also like to get an explination of the dead section of two adjacent tracks and how the definition if each track circuit is created Each JTC is created by an area of a given frequency - the boundaries of the dead section are created by track bonds AIUI In the green and purple areas, this is the area where an axle might not (green) and definately not (purple) drop the track circuit. I have a vague feeling that the minimum drop shunt for a single axle is 0.3 ω ie about a third-of-an-ohm. HTH. So these are very similar to traction immune 21 track circuits. They have a 20m "tuned zone" where the different frequencies repel each other. Are the impedence bonds just there to tune the rails to the correct frequency or do they serve a another, greater purpose? Lastly, what does AIUI mean?
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