Kato switch (point) question

[Nick_Burman]

Hi all,

 

 

Do the Kato Unitrack switches have internal end-of-throw disconnects to stop the flow of power to the electromagnet, or is the disconnection done inside the switch lever?

 

 

Cheers NB

[KenS]

It's in the switch lever, which is a momentary-contact switch.  You can burn the magnet out if you use an always-on switch.

[David]

You can burn the magnet out if you use an always-on switch.

 

Or hold the lever at the midpoint, you can hear the switch buzz. The Tomix levers are sprung a lot hard then the Kato, maybe to prevent this kind of accidental damage (though it makes them super loud when they go "SNAP").

[Nick_Burman]

It's in the switch lever, which is a momentary-contact switch.  You can burn the magnet out if you use an always-on switch.

 

 

 

Is there any way one could emulate this momentary contact action using ordinary electronic components?

 

 

Cheers NB

[inobu]

Inside.

 

The switch contact are stiff wires bent in a fashion where the level forces contact as it passes through from one position to another. The angle in the bend does not allow it to remain in the contact position. It's crude but effective.

[inobu]

It's in the switch lever, which is a momentary-contact switch.  You can burn the magnet out if you use an always-on switch.

 

 

 

Is there any way one could emulate this momentary contact action using ordinary electronic components?

 

 

Cheers NB

 

Electronic switching is a funny concept in that you end up replicating a manual function twice. Then design in essence is a manual function (human pushing button) that activates a solenoid (electronic component pushing a button) to activate a target contact.

 

If you are trying to simplify your setup them you might need this

If you are trying to automate your system then you need this

 

 

which means you need to go DCC which is a expensive endeavor and causes one to go back to this

 

.

[Nick_Burman]

It's in the switch lever, which is a momentary-contact switch.  You can burn the magnet out if you use an always-on switch.

 

 

 

Is there any way one could emulate this momentary contact action using ordinary electronic components?

 

 

Cheers NB

 

Electronic switching is a funny concept in that you end up replicating a manual function twice. Then design in essence is a manual function (human pushing button) that activates a solenoid (electronic component pushing a button) to activate a target contact.

 

If you are trying to simplify your setup them you might need this

If you are trying to automate your system then you need this

 

 

which means you need to go DCC which is a expensive endeavor and causes one to go back to this

 

. 

 

 

Thanks inobu...what I’m thinking is that one day I’ll want a junction fitted with a proper interlocking lever frame (such as the one furnished by Modratec of Australia - www.modratec.com) and set up using Kato switches, however I need some kind of switch which I could tack to the lever rods which would furnish the necessary power “blip” to move the switches.

 

 

Cheers NB

[KenS]

Thanks inobu...what I’m thinking is that one day I’ll want a junction fitted with a proper interlocking lever frame (such as the one furnished by Modratec of Australia - www.modratec.com) and set up using Kato switches, however I need some kind of switch which I could tack to the lever rods which would furnish the necessary power “blip” to move the switches.

 

What you would need to make that work is a switch that momentarily sends current in one direction when set one way, and momentarily sends current in the other direction when moved the other way.  That's a problem.  Then you'd need to mechanically couple it to the lever frame, so that pulling the lever throws it one way, and pushing the lever throws it the other way.  That's not too hard if you're mechanically inclined (levers and springs at worst).

 

The switch is what would be described as an (on)-(on) DPDT (the parenthesis around "on" indicates it's momentarily connected, not continuously connected).  The problem is that, as far as I can tell, they don't make those (other than in the form of Kato's blue switches and similar, which appear to be too large for what you want).  One solution is to couple an on-on mini DPDT (always on) switch wired as a reversing switch with a momentary push button, which is how the old Atlas turnout switches worked (slide the switch to reverse current, then push it down briefly to make contact).  With that, you could mechanically couple an on-on DPDT wired as a reversing switch to the frame, throw the lever by hand, and then push a button in front of the lever to throw the turnout. Not quite prototype, but only one button and you would need to use the lever frame, so somewhat prototypical.

 

Alternately, you could make something with brass strips and some copper-coated PCB strips (the kind sometimes used for ties) so that the lever frame moved a contact over two contact points, leaving it on a dead spot at either end.  What that would do when you threw the lever is first throw the turnout in the direction its already set (which does no harm), then as you move the lever further throw the turnout in the other direction, before coming to rest in a position with no current flowing.  The only hard part might be that there isn't enough travel in the lever frame, and you'd need to use a mechanical lever to increase the throw distance to fit in all the contacts and dead spots needed.

 

Finally, there are ways to make an on-on switch act like an (on)-(on) switch, but they require more complex circuits.  There is a nice set of examples on this page (I don't understand the first diagram, but the second one with the SPDT looks like it would do what you need). With one of those, you could just couple the on-on switch to the lever frame and throw the lever to throw the turnout.  But you'd need to replicate the circuit for each lever.

 

An on-on mini switch, in either SPDT or DPDT forms, is fairly common.

[dickturpin]

Many years ago my father made me the attached lever frame for points similar to Unitrack. It may help someone.

 

Richard

[quinntopia]

Is there any way one could emulate this momentary contact action using ordinary electronic components?

 

Cheers NB

 

Nick;

This is a question I've been pondering for several years and have been looking for solutions myself.  What I ultimately decided to go with was something called the 'easy BCD circuit' which is a relatively simple circuit you can build yourself out of some easily available and cheap parts (a capacitor, resistors, SPDT toggle switch, bi-color LED (for direction indication), and some diodes and wire) and your in business!  I'm an electronic/electric misfit and I was able to build about 14 of these for my layout....and I am super pleased with their performance!

 

The circuit in question that I used was designed by a gentleman named Ray Stilwell and he haunts the Yahoo Unitrack Groups.  The very bottom of this post on that forum provides his email address to contact him for his design:  http://groups.yahoo.com/group/KatoUnitrack/message/7931