Hi,

I experienced my first failure in C track turnout motor yesterday.
The turnout did not respond to the control sent by the PC. After investigations it appeared that it was not an electrical failure, but a mechanical one: After removing the motor, I saw that the mobile rod was stuck (stongly stuck), at full stroke.
I can't understand what happened: nothing has burned (I opened the motor to check) , the end stroke switches are electrically and mechanically working, the coils have a standard 20 Ohm resistance.
Had Anybody already experienced this problem?
How can it be explained?
Thanks for your help
Fred

Where did you use K83 or 74460 decoder for the 74490?

two possibilities come to mind.
1) there is/was a short to the metal case which in turn shorted to the centre rail - result solinoid energised for a long time heating wire insulation/former/actuator(rod)
2) software is not sending a shutoff command (code Dec32). result = as above with solinoid energised too long.

Note: The later certainly applied to earlier motors with only one switch, however I am still wary of the actual design/adjustment of these cutoff switches. In some cases the rod has enough slop to allow the switch to 'not' activate.

Thanks for your answers.
It's true that a permanent voltage is applied on the coil, and that a failure in the end shut off contacts would be critical. Up to now, they seem reliable....fortunately.
Nevertheless, I find it strange that the rod is "glued" at full stroke with the end contact opened, as it should be.

Fred