View single post by Helmut
 Posted: Fri Nov 25th, 2016 12:47 pm
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Joined: Sun Feb 17th, 2013
Location: Friedberg, Germany
Posts: 1189
For years, I have been helping other people to make their layouts operational. One of the critical issues always was the reliable operation of turnouts. In Germany, the ubiquituous H0 brands used are Märklin and Roco/Fleischmann. Their standard solenoid turnout motors have a tendency to become a bit sticky with age, that is >3yrs. This is also true for the actual M.  C-track system. Generally no problem, but if you try to operate some of them in parallel, e. g. in a crossover, one or both of the motors will get stuck halfway, especially after you operate them after a longer break. This is most annoying with Märklin C-track, as the motors are mounted underneath the turnout and no longer are easily accessible once the tracks have been put down and embedded in scenery.
The 16VAC simply do not suffice. I've devised two CDUs that cured these problems once and for all.
The upper sketch is normally sufficient for everything except Märklin, whereas the lower one has proven to operate up to four Märklin drives satisfactorily. It is a voltage doubler delivering some 40V, which in turn provides enough current for that split second it is needed to throw the switches over.
The lamp serves as current limiter, charge and problem indicator. As most of today's drives have a built-in cutoff at the end of travel, a lamp that stays on when one pushes the respective button twice shows that there is either a stuck turnout or a cutoff that is shorted out.

Attachment: CDU.jpg (Downloaded 17 times)

Last edited on Fri Nov 25th, 2016 12:50 pm by Helmut

Regards, H.
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