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DC powered turntable and DCC (w/sound) equipped locos?

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  • Member since
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  • From: N. Padre Island- just off the coast from Corpus Christi TX
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DC powered turntable and DCC (w/sound) equipped locos?
Posted by LooseClu on Friday, October 10, 2008 3:58 AM

I'm building a 61' Diamond scale HO TT for my logging engines which are DCC sound equipped.  The TT is older than DCC and picks up current from wipers in the center shaft and the pit ring track.  I've been told I should power the TT track with a seperate 12V DC power pack.  Would that in anyway annoy my decoders (two Tsunami micro 750's and one TSC motor only)?  I am an old man who just doesn't pick things up quickly; I originally gave up my initial HO train habit when they started making only 12V new stuff and all my gear was 6V.  I was then 15 and just bought my first auto (an old 1930 Essex 2-door junker) that needed all my available funds and more.  At my advanced age I got back into little trains and realize I still don't know diddly about electricty.  The DC powered turntable track (hand cranked) I can deal with.  I have this fear of frying expensive decoders and do not know if what was suggested would work with or fry the decoders.  I could sure use the advice from you experts out there and a brief explanation as to why it will or won't work would also be helpful to my admittedly slow learning process.  TIA Roy  

Roy         Onward into the fog                 http://s1014.photobucket.com/albums/af269/looseclu/

  • Member since
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  • From: Bedford, MA, USA
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Posted by MisterBeasley on Friday, October 10, 2008 6:23 AM

There is no reason to use a separate power supply for the turntable track.  They may have been talking about using a separate supply for the turntable motor, however.  But, it sounds like the turntable is manually driven by a hand crank anyway.

If the turntable automatically sets the track polarity correctly from the wipers, then it should work just fine with DCC.  If you need a reversing switch in DC, then you will also need a reversing switch in DCC.  However, in DCC, you have the option of using an auto-reverser unit, so that you can let the electronics handle the polarity automatically.

By the way, I'm currently assembling an Essex from Jordan Miniatures for my own HO layout.

And welcome aboard!

It takes an iron man to play with a toy iron horse. 

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Posted by rrinker on Friday, October 10, 2008 7:41 AM

 Ditto. The turntable motor system - th eone that spins the table, probably won't operate on DCC. If it has any sort of indexing system - where you can set it to go to a specific point,t hen it surely requires DC. If it's just a motor you will manually stop and start to align the turntable bridge, it IS possible to hook a DCC decoder to it and control it that way. You'd have to check the current draw of the motor and so forth to see what sort of decoder would actually work.

 As for the rails on the turntable - if it uses a split ring rail to automatically swap the polarity as the table turns, you need to make sure the gaps are long enough so that both aren't spanned at the same time - in other words there has to be a small dead spot, otherwise as the table rotates it will short out. You can use a DCC autoreverser to power the bridge track so when a loco enters or leaves the turntable, the polarity is automatically switched. The downside of the split rail is if you use sound locos - if you spin the loco all the way around, it will stop the sound over that momentary dead spot and then the sounds will restart when power comes back on, not too realistic, if you're concerned about that. You can also use continuous power to the bridge tracks where there is no gap, and hook up a DCC autoreverse to handle the polarity switch. That way the track power is never dead at any point. Downside is any sort of connection for this is usually more complicated - you can't just hang wires down, unless you were always careful to do about as many clockwise turns are counter-clockwise, or the wire will just twist up. I've seen a lot of scratch built ones use a 1/4" phone jack as the pivot and power pickup, but adding somethign like that to a kit might not be posisble, or at least not easy.

 

                                --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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  • From: S.E. Adirondacks, NY
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Posted by modelmaker51 on Friday, October 10, 2008 8:54 PM
 rrinker wrote:

 Ditto. The turntable motor system - th eone that spins the table, probably won't operate on DCC. If it has any sort of indexing system - where you can set it to go to a specific point,t hen it surely requires DC. If it's just a motor you will manually stop and start to align the turntable bridge, it IS possible to hook a DCC decoder to it and control it that way. You'd have to check the current draw of the motor and so forth to see what sort of decoder would actually work.

 As for the rails on the turntable - if it uses a split ring rail to automatically swap the polarity as the table turns, you need to make sure the gaps are long enough so that both aren't spanned at the same time - in other words there has to be a small dead spot, otherwise as the table rotates it will short out. You can use a DCC autoreverser to power the bridge track so when a loco enters or leaves the turntable, the polarity is automatically switched. The downside of the split rail is if you use sound locos - if you spin the loco all the way around, it will stop the sound over that momentary dead spot and then the sounds will restart when power comes back on, not too realistic, if you're concerned about that. You can also use continuous power to the bridge tracks where there is no gap, and hook up a DCC autoreverse to handle the polarity switch. That way the track power is never dead at any point. Downside is any sort of connection for this is usually more complicated - you can't just hang wires down, unless you were always careful to do about as many clockwise turns are counter-clockwise, or the wire will just twist up. I've seen a lot of scratch built ones use a 1/4" phone jack as the pivot and power pickup, but adding somethign like that to a kit might not be posisble, or at least not easy.

 

                                --Randy

 

Did you even READ the OP's post???

 Quote: The TT is older than DCC and picks up current from wipers in the center shaft and the pit ring track.

 Quote: The DC powered turntable track (hand cranked) I can deal with

Jay 

C-415 Build: https://imageshack.com/a/tShC/1 

Other builds: https://imageshack.com/my/albums 

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  • From: Reading, PA
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Posted by rrinker on Saturday, October 11, 2008 6:05 AM

 People other than the OP read these things, the information is still valid. So it has steady power - use a DCC autoreverser, no issues. And there are many powering kits that work with Diamond Scale Models turntables.

 We're all here for information, and with the topic title I'm sure more people will look at this who had a turntable that has a DC motor to spin it and want to use DCC locos than people with SPECIFICALLY a turntable that has center shaft and pit rail power pickup.

 

                                  --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    December 2002
  • From: Overland Park, KS
  • 343 posts
Posted by dadret on Monday, October 13, 2008 6:46 AM
I have a Walthers 130' TT on my DCC layout - I use an old Atlas power pack to power the TT MOTOR but the track is wired into my DCC system and works fine.
  • Member since
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  • From: Mpls/St.Paul
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Posted by wjstix on Monday, October 13, 2008 8:43 AM
Ya I'm not sure why you would need a separate DC power source for the turntable tracks. Someone may have been talking about making the turntable a separate block so you can reverse polarity?? No reason you can't power the TT track with DCC, put in an auto-reverser and you're all set.
Stix

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