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Offline GG707  
#1 Posted : 04 June 2012 23:24:52(UTC)
GG707


Joined: 09/06/2010(UTC)
Posts: 45
Location: Athens, Greece
Hi,

After a full day at my workshop, I am proud to show you the work I've done.

it's about a turntable. I'll add extra info as soon as possible.

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GG707 attached the following image(s):
DSC00261.JPG
DSC00262.JPG
DSC00263.JPG
DSC00264.JPG
George G.
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Offline ozzman  
#2 Posted : 05 June 2012 05:07:15(UTC)
ozzman

Australia   
Joined: 23/11/2007(UTC)
Posts: 1,828
Location: Sydney, Australia
Very good George. Is it motorised?
Gary
Z Scale
"Never let the prototype get in the way of a good layout"
Offline steventrain  
#3 Posted : 05 June 2012 08:14:09(UTC)
steventrain

United Kingdom   
Joined: 21/10/2004(UTC)
Posts: 31,601
Location: United Kingdom
Excellent.
Large Marklinist 3- Rails Layout with CS2/MS2/Boosters/C-track/favorites Electric class E03/BR103, E18/E118, E94, Crocodiles/Steam BR01, BR03, BR05, BR23, BR44, BR50, Big Boy.
Offline kariosls37  
#4 Posted : 05 June 2012 12:14:17(UTC)
kariosls37

New Zealand   
Joined: 02/01/2009(UTC)
Posts: 1,067
Location: Auckland, New Zealand
Nice turntable. It looks very solid. Are you going to paint it as well?
Offline intruder  
#5 Posted : 05 June 2012 12:57:30(UTC)
intruder

Norway   
Joined: 16/08/2006(UTC)
Posts: 5,382
Location: Akershus, Norway
Very interesting, George!
Best regards Svein, Norway
grumpy old sod
Offline GG707  
#6 Posted : 06 June 2012 15:15:12(UTC)
GG707


Joined: 09/06/2010(UTC)
Posts: 45
Location: Athens, Greece
Hi,
Thanks everybody.

Yes it is motorised.
I have used the turnable mount of a game crane, that needs 1,5 volt to run at a scale speed,and also there are brush contacts to pass the electricity ,at the line of the turntable.
GG707 attached the following image(s):
DSC00266.JPG
DSC00267.JPG
DSC00269.JPG
George G.
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Offline steventrain  
#7 Posted : 06 June 2012 17:55:48(UTC)
steventrain

United Kingdom   
Joined: 21/10/2004(UTC)
Posts: 31,601
Location: United Kingdom
Very good work.
Large Marklinist 3- Rails Layout with CS2/MS2/Boosters/C-track/favorites Electric class E03/BR103, E18/E118, E94, Crocodiles/Steam BR01, BR03, BR05, BR23, BR44, BR50, Big Boy.
Offline kbvrod  
#8 Posted : 06 June 2012 22:01:00(UTC)
kbvrod

United States   
Joined: 23/08/2006(UTC)
Posts: 2,597
Location: Beverly, MA
Hi George,all,

Looks great!How are going to index it?

Dr D
Offline GG707  
#9 Posted : 06 June 2012 23:18:46(UTC)
GG707


Joined: 09/06/2010(UTC)
Posts: 45
Location: Athens, Greece
well, "targeting" is going to be analog.
George G.
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Offline kbvrod  
#10 Posted : 06 June 2012 23:41:47(UTC)
kbvrod

United States   
Joined: 23/08/2006(UTC)
Posts: 2,597
Location: Beverly, MA
Hi George,all,

Originally Posted by: GG707 Go to Quoted Post
well, "targeting" is going to be analog.


Very good!ThumpUp And build your own controller?


Dr D

Offline hgk  
#11 Posted : 07 June 2012 07:09:10(UTC)
hgk


Joined: 10/11/2006(UTC)
Posts: 455
Location: Pacific Ocean
Hi George,
If your looking for a simple manual control something like this should work (although not tested for this application).
A spring loaded roller on the fixed side and half round notches on the
rotating table, should work for a detent. That slip ring crane device is a great find for powering the track.
Let me know if something isn't clear.
-George

switch wiring
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Offline GG707  
#12 Posted : 09 June 2012 11:14:06(UTC)
GG707


Joined: 09/06/2010(UTC)
Posts: 45
Location: Athens, Greece
Originally Posted by: hgk Go to Quoted Post
Hi George,
If your looking for a simple manual control something like this should work (although not tested for this application).
A spring loaded roller on the fixed side and half round notches on the
rotating table, should work for a detent. That slip ring crane device is a great find for powering the track.
Let me know if something isn't clear.
-George

switch wiring


Goodmorning,

So i have to align reed switches at the end tracks, and use two magnets on the sides of the turntable in order to "read" the right position... so i can turn it manually until i get close to the one i want, and then i release it, but it will continue until it gets on the right posiition... very smart and simple , thanks :)

Or, I could possibly use some tamber swiches instead of reeds, for more accurancy...

Edited by user 09 June 2012 16:19:03(UTC)  | Reason: add text

GG707 attached the following image(s):
1280828055606_hz-myalibaba-web11_20.jpg
George G.
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Offline hgk  
#13 Posted : 10 June 2012 09:04:05(UTC)
hgk


Joined: 10/11/2006(UTC)
Posts: 455
Location: Pacific Ocean
Originally Posted by: GG707 Go to Quoted Post
Originally Posted by: hgk Go to Quoted Post


Goodmorning,

So i have to align reed switches at the end tracks, and use two magnets on the sides of the turntable in order to "read" the right position... so i can turn it manually until i get close to the one i want, and then i release it, but it will continue until it gets on the right posiition... very smart and simple , thanks :)

Or, I could possibly use some tamber swiches instead of reeds, for more accurancy...


Hi, Some comments,
1. You only need one magnet on the turntable. (The reed switches are shown in a straight line but would actually be wrapped in an arc).
Each track position needs a detent notch on the turntable to mate with a single roller mounted somwhere on the fixed side. That will
hold it in track alignment when stopped regardless of the turntable approach direction. There isn't anything to be read but by using a second or
a SPDT switch instead of SPST, that could then be used to say turn on a lamp on a panel board to indicate which track your at.

2. That's correct about the general theory of operation.

3. The switches with rollers would work, but by coupling both the mechanical position and the electrical motor stop into one might actually make it more fiddly to
adjust. With more rollers there would also be more stiction and friction to overcome on the mechanism.

4. For the reed design there would be one roller on the fixed side and a detent notch for each track. The detents to roller have to be made accurately
to position the track but can be mounted anywhere. Then a reed switch can be accurately mounted in front of the magnet to denergize the motor. It doesn't have to be on the face of the turntable, it could be underneath and the switches looking up, for example. Track spacing is not a factor it can be whereever you want it to be.
As the reed switches are a small glass tube and have to face the magnet they would need a clever mounting method (you have to be sure of proper operation before the epoxy putty dries :)

Let me know if anything is unclear.
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Offline hgk  
#14 Posted : 10 December 2013 21:07:53(UTC)
hgk


Joined: 10/11/2006(UTC)
Posts: 455
Location: Pacific Ocean
Hi GeorgeG,
I just went back to the posting to review what I said and if you have any questions I'll be glad to try and help.

I don't see why you couldn't use a single N.O. tamber? roller switch mounted on the fixed side and have the
detents for it on the moving wheel. The trade off is that the detent wheel has to be made perfect as it would be
a pain to make adjustable detents. In that regard it may be easier to use a N.C. reed switch as it's somewhat easier to
relocate a magnet.
I would probably recommend using a simple test rig to test things out,
then you can work out the best way to incorporate it on the real turntable.
One objective is to try to get enough detent force to reliably hold the track position without overloading the motor when moving.
If the switch alone doesn't hold the turntable stiff enough you could always add a second friction roller somewhere.

-George
ps
I'll also put this on the forum in case it can be of use to someone else in the future.

Edited by user 17 December 2013 19:35:28(UTC)  | Reason: Removed p/m quote from posting. Edited N.O. reed sw. to N.C.

Offline mbarreto  
#15 Posted : 10 December 2013 22:15:36(UTC)
mbarreto

Portugal   
Joined: 18/02/2008(UTC)
Posts: 1,257

I like your idea of build a turntable. It also look nice.

My thoughts about it, just for reflection.
I think it is not easy to do, but one way of have enough force to keep the bridge inline with the exit tracks, is to have a hole below each exit track and have something like a turnout motor sending a small iron into the hole. The hole could be a little conical on the bridge side and cylindrical just after as this would facilitate the entering of the small iron into the hole.

An alternative to reed switches maybe for example an optical sensor under each track and have a LED (or some other liht source) under the bridge.

One thing that impresses me on your turntable is the bridge weight. I don't what it is, but it really seems heavy. With 3 pieces (at least) of plywood it could be lighter (depends on the plywood thickness, off course): One for the track bed and 2 horizontal below, one on each side. Probably you need some reinforcement in the middle...
Best regards,
Miguel
Mostly Märklin H0.


Offline Frankenbahner  
#16 Posted : 12 December 2013 00:41:14(UTC)
Frankenbahner


Joined: 15/09/2006(UTC)
Posts: 625
Location: Nuremberg, Bavaria
Excellent work!

Regards,
Florian
H0 3-rail AC with DCC, MM and mfx, 2-rail DC streetcars, and N gauge
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