Hello,

this discussion exists even in german forum.

The end switchs seem to be very sensitive to DC coming from decoder (inductive switch current)

They tested: a turnout motor which was not working in digital anymore, was tested in AC and it worked fine again.

I have absolutely no problem with my 15 years old 7549 K switch motors.

They run digital on 5211 decoder and separate power feeding through 5214 Powermodule (DC)

I eliminated the end switches long time ago.

kind regards

Stephan

I expect that it is the two switches that cut the power from the coils when the piston is reaching the end positions. If either switch fails the current will continue to flow if not controlled by a short pulse and finally burn its corresponding coil.

Hello Supermoee,



Yes, this is what we saw too, (though I don't speak german...).



The V5211 makes DC current as the marklin one, it seems only LDT does provide AC to the turnouts.

Emmanuel

In fact, that might be a problem, but the very most current encountered problem is the opposite: the current can't flow through the switch for there is a small insulation layer on the copper contact of the micro switch. That insulation layer is due to the sparks that appear each time the switch opens, and due to the inductive load.

Seems there are only 2 good solutions:
- short the microswitches
- connect a transil or 2 series zeners in parallel to each microswitch (if used in AC), or a diode (if used with k83;

Using a capacitor in parallel to the switch lowers the sparks, but do not eliminate them. So the problem will appear again later ...

Of course an other solution is to use an other brandt. Viessmann is just releasing its turnout motor, but it's too early to get an idea of its reliability.

Seems also that some people have not yet got the trouble. Probably beter switch quality.

There are other threads on this forum on the same subject.

Fred

Hello Jeehring

I bought k83 decoder earlier than 1992, Märklin digital came out 1985.

The C track came out on 1996

discussion about the poor quality of Märklin turn out motors are existing in forums since public forums are existing on the internet. The 7549 moto for K track in the 80's had a lot of problems, the new version of 2000 has the same problems.
For the C-track motor the poor quality of the first series is well known that's the reason why Märklin made an improved version some years later, but still not working properly in all condition

The fact that you never heard about these problems does not mean that these problems are not existing. You just have to listen to

Just type in Goolge Märklin 7549 / 74490 problem (or defekt (german)). You will wonder how much hits you will find on this topic

The best Märklin turnout motors are the one of the M track switches and the old K track switches with large, fix assembled motors. These work even after 30 years.


rgds

Stephan

I have 11 installed C track turnout solenoids, and about half of them give me problems as described. That is, the end contact switch goes open circuit and the motor does not get any current. My track is bedded in to the ballast, so it is impossible for me to change or adjust these motors, which leaves me a huge problem.

I have one solution that works, but it requires the manual lever to have been left in place. Dribble a bit of Marklin oil down the mechanism from above and operate it repeatedly a few times. After a few minutes the "dodgy" solenoid comes back to life and continues working for a few weeks.

In the future if I mount turnout motors under the trackbed I will cut access holes in the baseboard to be able to replace or service the motors from beneath.

If you'd like to see threads posted on the forum, you just have to make a "search".
To do so:
-click on"login"
-click on "search"
-fill up the forms.

If you don't success, just ask Juhan or other member of this forum that will explain better than me.


Of course you have the right to say anything,

except to be insulting to other members that reported their problem.

You have also the right to say


but reports show clearly that it's mainly an electrical problem.

So you may have an opinion, but if I were you, i'd try not to be ridiculous.

But no problem: you are in your right!

Fred

At last back to the original question, Well done, Antonio.
You removed the end switches, that would mean that the turnout solenoids are activated by a pulse, do you happen to know the length of the pulse?
Is the pulse length settable to different lengths?
Have your turnouts behaved flawless since the removal?

I'm glad that some people don't have any problems. As I said above, about half of my motors have end switches that only work intermittently. Others have had the same problem. It's a known problem.

I think that is exactly what this thread is trying to canvas..

From my own experience there are a couple of possible issues. All of which I have encountered to one degree or another.

- micro switch not working
- - internal (only once and may have been caused by an external short causing arcing)
- - physical - mounted on circuit board to far away from actuator (switch had guide pins for the board but appeared malformed - ? bad batch)
- Casing aperture for armature poorly formed (again bad batch ?)
- - cause drag and poor throw of switch
- - in combination with the switch cutting out too soon actuator does not get to the end
- Similar to above, the armature itself was bent or swollen (melted?)
- Too much power to motor
- - causing bounce back
- - in combination with the switch cutting out too soon means the armature is NOT Redriven to the end.

So in general , while there is good logic in cutting power when the armature is thrown, there are a number of real world vagrancies that come to the fore that might have otherwise gone under the radar because of the little bit of extra/concerted grunt. If the drag or bounce back is only minor and consistent then bypassing the switch (in pulsed digital) may be OK. However it does remove one line of defense should there be a real issue upstream.
One example from personal experience is PC programing and forgetting to issue the "off" command which was sometimes needed explicitly (200ms) after an "on" command.

Usually the items become reliable enough after some fiddling which could be
- tweaking the position of the switch
- filing the aperture and/or armature to prevent dray, or sometimes removing the manual lever is enough
- inserting drag/resistance (ensuring lever is in place).
- reducing power (this is what the resisters that come with a k83 are for)
- reducing pulse width as defined in the Central station/PC.
Products appear to have become more reliable but I concur that in the early days one was just inclined to "cut to the chase" and bypass the switch

And this was exacerbated by the inaccessibility of the motors (under the C-Track roadbed). from which we learned that cutting an access hole under the baseboard was a very prudent measure.

I can only presume that the inclusion of the switch(es) is because the newer motors were not designed like those of M-Track to allow for 100% duty, with the possibility of a Loco pickup/shoe to stop on top of the contact switch for an extended period of time. In digital operation there should (!?!?) be no such issue as the motor is only pulsed.

A separate issue but relates to the burnout scenario.
- the centre rail comes in contact with the metal housing AND the internal components (coil,circuit board etc) are also shorted to the metal housing

you don't like frog fight ???

With these shady goings-on , Little Casanova is probably trying to confuse the reader....
He can't accept the fact that he's not so young any more...may be ?

Hello,



Hello,

Did you have troubles befoire removing end switches ? Were they with both LDT and k83 (if you remember it?)?

Have you had s88 turnout feedback positionning ?

Thanks,

emmanuel