DCC Turntable, with a mind of its own

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#242135 (In Topic #13389)
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Reversed polari

Hi, My Frateschi Turntable, suitably chipped, has worked perfectly for yonks. I decided to change entry into layout, and re routed it, via point, suitably adapted, EG, with soldered wires, as per all the others. Point and track, work a treat, but  when it enters tt, Short occurs, As  , an aside, TT, on number 022, still runs perfectly.  Not only, has the polarity reversed at TT, but also, on 3 tracks, at the far end, leading to Engine sheds. When testing with  bulb, its fine on layout, up to TT, then lights up on other rail, on TT, and 3 loco sheds.  The only thing that i have changed, is where TT, enters layout.  Baffled.  Help. john
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Dont know a Frateschi Turntable but most turntables have a place where the polarity reverses perhaps you new entry road is just over the point of polarity change hence the short.

Brian

OO gauge DCC ECOS Itrain 4 computer control system
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[user=2137]Briperran[/user] wrote:
Dont know a Frateschi Turntable but most turntables have a place where the polarity reverses perhaps you new entry road is just over the point of polarity change hence the short.

Brian

I would agree with Brian…..I would check the point where polarity changes.

If that doesnt provide the solution a before and after sketch map would help

Good luck

John

John
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Thanks guys, you could well be right. Its not supposed to happen with this TT, as it takes up to 18 exits. However, once in the past, my point clips melted the sleepers, and that was a possibility then. What i dont understand is that new connection to track, was a previous  siding exit, ans that was not a problem. Will  run it tomorrow to find out, when/ if polarity changes. The other solution, i suppose, might be to reverse feed to TT.
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I thought these turntables could only have one entry track. The split ring design means that the polarity changes after I think 90°. Changing the position of the entry will mean some exits have the wrong polarity. One of the downfalls r this design.

Nigel

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Hi, Nigel. yup. that is probably, what i have done, changed entry from point 1 to point 15, say. The TT has 18  positions, with  1 being entry , and the other 17, exits.  Will have to return to drawing board, thanks. john
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Can you rotate the whole turntable assembly so that the entry point is back at 1?

Jeff Lynn,
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Hi, Jeff, thanks foe your reply. Yes, this may be the way i have to go.. You make these alterations, on the spur of the moment, then find, you hit all kinds of snags. Intend to rotate either TT, or relay track, asap. john
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Sorted it, by reversing power feeds on TT, and other exits. Still at total loss to understand, how, polarity reverse occurred. Magic / spooky. john
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