Maerklin K-track switches: is a real feedback possible?

[Caralain]

Hello:

I am using Maerklin K-track switches. After a recent failure of the blade to turn properly in one of my switches (not because of a failure of the servo motor but due to a mechanical problem of the blade), I noticed that Windigipet offers real position monitoring / feedback (Stellung Ueberwachung).  Per the German instructions, it can only be accomplished by changing or modifying the hardware of the layout (see page p.241). Unfortunately there is no indication how it can be done. In the English edition (p. 194), it is alluded to some Lenz decoders or ESU SwitchPilot with RailCom. So what are the real possibilities of monitoring the real position of the blade, and is there a solution adapted to Marklin K-track switches?

[jcerainh]

Hello

 I also am using Maerklin K-track switches.
The blue cables of these motors, I'm also connecting them into a S88 each one to an imputs. These imputs are those that I use in WD2012
 to know to the real position of the switches, using these retro contacts as conditions in WD.

 my English is quite bad

Regards,
Jaime

[Caralain]

Hello Jaime:

This is a possibility, but it doesn't tell you if the switch has been thrown or not. What it does is to inform the S88 that the electromagnet has moved one piece of metal from one end to the other end. Imagine that your S88 has received data indicating that the motor has changed position. If for some mechanical reason the piece transmitting the motion from the motor to the blade is unable to work, your S88 will still indicate that there was a change in the position of the motor, but the blade won't have moved at all.

It's the real problem. I believe that the solution to have a real feedback of the turnout's position is mechanical, not electrical. I mean by that there should be a sensor of some sort able to "sense" that the switch - not the motor - has be thrown or is still straight. It may be not possible with Maerklin K-track turnout because of the way they are built.

[Ralf Krapp]

Hello Pierre,
this - your - problem has been discussed some times in this forum, but there was no real solution how to solve this problem. My idea is this: on both sides of the rails where the blade is in contact with the rail, this part of the rail is to be isolated by cuts left and right from the contacting area. Then a wire has to be solderd to each of these areas and put to two contacts of a S88 decoder. When the blade is moved from straight ahead to turn aside the  feedback-contact will indicate the change of the blade. The only thing you must obbey is the properly contact between the blade and the rail left or right. If you use servo motors (not these original Märklin motors) you can adjust the power of the actuator to have good electrical contact between the blade and the rail.
In the WDP-layout you can instal two indicators which are able to show the feedback.
I hope my discription is understandable. Myself I haven't yet made such an istallation, but I took away those contacts inside the Märklin-motor which cut off the power after switching (so called "Endabschaltung"- may be "final cut off"). So the motor gets more strength to move the blade. Up to day I had no problem with a turn-out that is of no good function.

[Caralain]

Hello Ralph;

I thank you for your answer. Your description was perfectly understandable and confirms what I thought: that you have to isolate the parts of each rail in contact with the blade. I am not sure if I will do that, because the cuts have to be very precise in order to not damage the turnout. I use myself the ESU servo motors and I am very happy with them. It's very rare I have a malfunction, and when I have one it's not the servo motor itself, but some mechanical part transmitting the motion. I can probably live with this little margin of uncertainty for now, but will keep my eyes open in case there is a solution!