Wiring a turntable used solely for turning a loco through 180 degrees

[Brinty-1936]

It occurs to me that if I were to wire the rails on the TT to my track power supply, when rotated 180 degrees, there would be situation where the 'left' track would now be the 'right' track and I foresee an electrical problem relative to the main track. Would an automatic reversing loop module take care of this situation?

Another thought I'd had was that if I don't wire the TT rails, but instead have 'wipers' so that power could be picked up from the main track when the TT is in its new position. Is this a daft idea?

[mlehman]

An auto-reverser will work.

Yes, you can arrange the pickups from the ring rail so that the gaps and feeders reverse the power simply by the TT rotating 180. Most track wiring books cover this. It's easier to see in a graphic than to explain in words.

The Atlas TT does this as it turns, for instance...or did I hook that up to one of my auto-reversers? It's heck getting old. In any case, use only one form of reversing on a TT or things get confused.

[skagitrailbird]

I used an OG-AR by DCC Specialties on my TT that is only used to turn locos 180 degrees. I believe it to be much more reliable (and easier to hook up than making wipers, etc).

I power mine through a spring loaded center off DPDT toggle and have placec little blocks on the pit floor to stop the bridge to line up with the lead track perfectly. As the bridge approached the block I nudge the toggle to bring it in slowly. If I hit toe blocks to hard it makes the bridge tilt over a bit.

Good luck.

[RR_Mel]

 

When I assembled my CMR turntable I chose to not use the auto reversing pit rail system and as Mike says it can be confusing.  I built a custom superstructure on my bridge with a control house on one end so that I know which end is up.  It’s still confusing at times.

 

 

Mel

 

Modeling the early to mid 1950s SP in HO scale since 1951

 

My Model Railroad   

http://melvineperry.blogspot.com/

 

Bakersfield, California

 

I'm beginning to realize that aging is not for wimps.

[DigitalGriffin]

which make/model turntable.  The walthers one automatically handles polarity by using a split ring arrangement.  But this causes a drop out in sound.

[mlehman]

DigitalGriffin

which make/model turntable.  The walthers one automatically handles polarity by using a split ring arrangement.  But this causes a drop out in sound.

 

Yeah, that's another good reason to go with the auto-reverser option. AFAIK, built in TT reversing with gaps, contacts, etc will always have that drop-out, because they rely on that brief interruption in power to avoid the potential for shorting.

[carl425]

If I were using a turntable only for reversing locos I would drive it with a Switchmaster stall motor and just place blocks so that it stops where you want it. All you would need to do to reverse is throw a toggle switch.

Then you could use a micro switch to reverse the polarity of the bridge track.  If you were interested, this would also allow you to shut off the power to the bridge and/or approach track when it's not lined up.

DigitalGriffin

But this causes a drop out in sound.

I am a big fan of Keep-Alive - especially for sound decoders.

[rrinker]

 It's funny, on my last two layouts, which have been DCC, with sound locos, none of them ever cuts out, even over unpowered Atlas frogs. With no keep alives installed. On the club layout, with short fitter sections between sections, which only get power from (many times used) rail joiners - they do cut out.

 My conclusion - keep alives are a subsitute for poor track wiring techniques. Masking the symptoms, not curing anything.

 Older locos what do not have all wheel pickup, it may be easier to add a keep alive than add additional pickups, in which case the keep alive makes perfect sense.

                        --Randy

 

[DigitalGriffin]

carl425

I am a big fan of Keep-Alive - especially for sound decoders. 

 

I am too.  But it's a little cost prohibitive with over 180 engines and some as small as a 0-6-0T

I replaced my wiper system with a slip ring system.  Much more reliable and no drop outs.  A GOOD slip ring uses spring loaded brushes set inside a brush guide on a commutated shaft.  The more you use them the more reliable they get as a soft carbon brush forms the shape of the shaft increasing the contact area.  The springs behind the brushes ensure a constant pressure better then the leaf contacts Walthers uses.

[mlehman]

DigitalGriffin

I replaced my wiper system with a slip ring system. Much more reliable and no drop outs. A GOOD slip ring uses spring loaded brushes set inside a brush guide on a commutated shaft.

Don,

True, but YOU made that, didn't buy it?

I'm not aware of a commercial product available to do that, but would like to know if I'm wrong about that. Most people won't go to that trouble or have the skills, but it sure sounds bullet-proof.

Carl,

That stall motor/180 only TT idea is a good one, will keep that in mind.

[rrinker]

 The CMR turntable kit has option to wire the pit rail for split ring or continuous which would use an autoreverser. Kind of ingenious.

                      --Randy

 

[DigitalGriffin]

mlehman

 

 

DigitalGriffin

I replaced my wiper system with a slip ring system. Much more reliable and no drop outs. A GOOD slip ring uses spring loaded brushes set inside a brush guide on a commutated shaft.

 

 

Don,

True, but YOU made that, didn't buy it?

I'm not aware of a commercial product available to do that, but would like to know if I'm wrong about that. Most people won't go to that trouble or have the skills, but it sure sounds bullet-proof.

Carl,

That stall motor/180 only TT idea is a good one, will keep that in mind.

 

http://www.mouser.com/Search/Refine.aspx?Keyword=slip+ring

http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR12.TRC2.A0.H0.Xslip+ring.TRS0&_nkw=slip+ring&_sacat=0

 

https://en.wikipedia.org/wiki/Slip_ring

 

 

Also available on ebay on the cheap.

 

[mlehman]

DigitalGriffin

http://www.mouser.com/Search/Refine.aspx?Keyword=slip+ring http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR12.TRC2.A0.H0.Xslip+ring.TRS0&_nkw=slip+ring&_sacat=0 https://en.wikipedia.org/wiki/Slip_ring Also available on ebay on the cheap.

Cool, thanks.

I'm good, but might come in handy for someone.

[Brinty-1936]

My appologies for not acknowledging all the replies received about this querie. Old age is going to get the blame. I neglected to ask for notification of replies.

Down here in Oz they have a polite name for blokes like me - "Richard Cranium" - or, to be blunt and personal, "Dick Head."

I will now sit down, pour myself a cold one and proceed to scrutinize these replies. Why a cool one you ask? Well, current local time is 1:00pm and the temperature is just over 22C or 73F and promising to get higher. If I have too many cool ones I'll probably get higher too.

[Brinty-1936]

Okay, I had one too many cool ones yesterday and fell asleep. I got excited about a Keep-Alive as I also (possibly because of poor track connections I think) have locos stall on points. So I thought here's the way to go - until I found that you need one for each loco. I've only got eight locos and at $60 each (excludingpostage) I'm glad I don't have 180 odd like DigitalGriffin.

Being on a pension doesn't leave much leeway for purchasing non-essential stuff. So, the next thought was a switch to turn motor on and off. Okay, now I've got the TT turning through 180 degrees, all I have to handle now is the track polarity. So I think to myself that if I use a DPDT switch, hooked up the right way, I can, with just one "flick of the switch" acheive both aims - or have I once again missed something?

Then again, the auto reversing loop seems promising. I'm using a Digitrax Controler DCS 51 and I see that they have an AR1 Automatic Reversing Controller. Now, while that will automatically take care of the track polarity, I still have the problem of stalling locos.

I'm intending to build another layout within the next few months (if I last that long) and this time, I'll keep the whole thing simple - like no, or very little, elevations, not too many turnouts and I intend to use settrack rather than flextrack. BUT, it will have a turntable - assuming I can get it to  function as planned.

So thank you to everybody who offered suggestions and I'll let you all know what the end choice was and how it works out.

Cheers,
Brian

[dante]

Brian,

Carefully test your locos over your turnouts. You might find that some (or all) might not cut out over dead frogs (mine doesn't), or if the problems are dead frogs, frog juicers (cheaper than keep-alives) will power them, or you might have only 1 or 2 short-wheelbase or limited pick-up or rigid-driver locos that need keep-alives. Do not despair just yet! :-)

Dante

P.S. I used frog-juicers on several dead frogs but had to add keep-alives to 3 pieces of motive power with either very short wheelbase or limited pick-up.

[Brinty-1936]

Thanks Dante, I'll certainly do that. At this stage I don't feel like giving up but I do get confused when what used to work once doesn't work now. One of the engines (I forget which one at the moment) stops and when I go to push it, it moves about 1/4 of an inch and stops again. It just keeps on doing that and I wonder if somehow or other it is causing a short circuit and the Digitrax controller is resetting a circuit breaker and applying power again. Brian.