 Joined: 23/02/2005(UTC) Posts: 800
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Hi, Using servo instead of solenoid motors in C track turnout requires precise positionning of the servo under the basement. Here is a solution that avoids that difficulty: it consists in fixing the servo directly on the turnout. That necessitates a rather big hole in the basement, but does not require any precision. Furthermore, that hole is smaller that the one many modelists make for fixing the standard solenoid motor, leaving the point in place.  If necessary, the servo can be removed for fixing:  Regards, Fred
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 10 users liked this useful post by efel
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 Joined: 23/07/2014(UTC) Posts: 8,467 Location: ENGLAND, Didcot
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So, as I see it, you have mounted the motor on the plastic cover of the point mechanism, is that correct?
How well does it work, i have wondered about doing a similar thing myself.
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Joined: 23/02/2005(UTC) Posts: 800
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Originally Posted by: kiwiAlan  So, as I see it, you have mounted the motor on the plastic cover of the point mechanism, is that correct? Yes Originally Posted by: kiwiAlan
How well does it work, i have wondered about doing a similar thing myself.
That works perfectly, but, as it's new, I can't say anything about reliabilty. I guess it's at least as reliable as the mounting under the basement which is very often used. Fred
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 Joined: 19/08/2008(UTC) Posts: 1,049
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Hi Fred,
Who makes these servos and what do you use to control them, M84 decoders?
Thanks,
Roger |
Modeling Immensee, mile/km 0 on the Gottard. SBB Era V.
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 Joined: 01/03/2008(UTC) Posts: 2,883 Location: South Western France
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That looks like an excellent idea!
That looks exactly like what I should do to replace a number of failing Märklin motors in my hidden station area!
Do I see it right that you have preserved the spring loaded action of the blade so that points can still be taken backwards without being set?
Cheers
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Jacques Vuye aka Dr.Eisenbahn
Once a vandal, learned to be better and had great success! |
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Joined: 23/07/2014(UTC) Posts: 8,467 Location: ENGLAND, Didcot
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Originally Posted by: rbw993 Hi Fred,
Who makes these servos and what do you use to control them, M84 decoders?
Thanks,
Roger The servos are small radio control servos. ESU market them along with a decoder/controller, and I have a feeling uhlenbrock do too. The r/c servos are also available on eBay, and several other decoder manufacturers make decoders that will drive them. One advantage of using such servos is that you can set the limits of motion for the servo arm, and the speed of operation by setting up the registers in the decoder. Great if you are using servos for things like crossing gates, or semaphore signals where you can have the arm give a little bounce to simulate the slack in the point rodding.
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Joined: 23/02/2005(UTC) Posts: 800
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Originally Posted by: rbw993 Hi Fred,
Who makes these servos and what do you use to control them, M84 decoders?
Thanks,
Roger Hi Roger, Any RC modelism shop sells such servos. Also ESU, Uhlenbrock and others. To drive servos, I personnally use ESU Switchpilot Servo, controlled with an intellibox. Regards, Fred
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1 user liked this useful post by efel
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Joined: 23/02/2005(UTC) Posts: 800
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Originally Posted by: jvuye ....
Do I see it right that you have preserved the spring loaded action of the blade so that points can still be taken backwards without being set?
Cheers
Hi Jacques, Presently, the link between the servo and the turnout is a 0.5mm piano wire, and the spring effect is too strong. I'll make some trials with 0.4 or 0.3 mm piano wire in order to improve that function. Regards, Fred
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1 user liked this useful post by efel
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Joined: 15/10/2006(UTC) Posts: 2,319 Location: Washington, Pacific Northwest
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Originally Posted by: rbw993 Hi Fred,
Who makes these servos and what do you use to control them, M84 decoders?
Thanks,
Roger Servo's have a 3 wire connection (Brown red orange, or black white red, typically), and their own signals - PWM (pulse width modulation). The way PWM works is you have a period of signal time and the % of that signal period the signal is high, vs the time it spends low (duty cycle), determines the degree of rotation the servo is presently in. So _|-----|___________ is one angle and _|--------------------|_ is a much further angle. The range through which the servo can rotate (its not 360 degrees necessarily, typically its 180 degrees) is servo dependent. The changing of that high time vs low time signal ratio determines how fast the servo prepositions. So a servo controller is required - something that can repeatedly feed a square wave signal with varying high and low levels that can be changed on the fly easily. Servo decoders are the ideal solution. |
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1 user liked this useful post by Minok
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Joined: 23/02/2005(UTC) Posts: 800
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Originally Posted by: efel Originally Posted by: jvuye ....
Do I see it right that you have preserved the spring loaded action of the blade so that points can still be taken backwards without being set?
Cheers
Hi Jacques, Presently, the link between the servo and the turnout is a 0.5mm piano wire, and the spring effect is too strong. I'll make some trials with 0.4 or 0.3 mm piano wire in order to improve that function. Regards, Fred Hi, With a 0.25 mm piano wire, the spring effect is roughly the same as the original one (i.e.without motor or with marklin motor). I think that a 0.3 or 0.35 mm should also work Regards Fred.
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1 user liked this useful post by efel
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Joined: 09/05/2011(UTC) Posts: 2,969 Location: Somewhere, But Nowhere Near Manchester, England
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Just curious if there was any update on this subject with regard to reliability and best piano wire to consider using.
I recently saw a 3D printed solution on Facebook but sadly did not take down any details, but the fixing attaches to the C-track and the motor then attaches to the fixing so it acts as a go between to control the movement of the switch.
Does anyone have any other updated solutions for fixing servo motors to C-track to make them more reliable? |
Don't look back, your not heading that way. |
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Joined: 19/07/2023(UTC) Posts: 20 Location: North Carolina, Charlotte
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Designed my own servo driver for the turnouts - works for both straight and curved one, but need a 3D printer to print them. They fit on the existing Marklin solenoid attachment and I wanted the servo horizontal to minimize the depth taken from the layer below. I did run 1K cycle on it and worked OK. If there's interest, I am OK sharing the STP and STL. 
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2 users liked this useful post by BenPerr
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Joined: 23/07/2014(UTC) Posts: 8,467 Location: ENGLAND, Didcot
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Originally Posted by: GlennM
Does anyone have any other updated solutions for fixing servo motors to C-track to make them more reliable?
I don't know about reliability, but there are quite a number of examples of servo mounts for C track on Printables and Thingiverse available for 3D printing. Some are duplicated across both sites.
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1 user liked this useful post by kiwiAlan
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