For those of you that said I was crazy and this could not be done, a company by the name of Iowa Scaled Engineering has made the MRServo-3 that is a slow motion switch controller with contacts for signals and polarity that works in DCC and DCC variants and also DC. It does this with sensors and by disconnecting power to the frog as it is moving.
The below link will explain much more.
http://www.iascaled.com/docs/mrservo/mrservo-manual.pdf
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
It's not 'automatic' the way an autoreverser or frog juicer works. It's 'automatic' the same way contacts on a Tortoise work. People have long used Tortoise contacts, and before that, whatever switch machines were available with contacts, to switch frog polarity.
The only thing new about this is that they use an extra output on their microcontroller to operate a second relay that turns off all power, then turns it back on after the movement completes.
Otherwise - I must strongly disagree with their position on setting the throw of the servo. Yes, you only have to do it once - PER MACHINE, and should never have to touch it again. But people with different thicknesses of subroadbed material are going to run into issue where the servo never quite reaches the end of their preset throw and stays engergized all the time - either burning up the servo or the controller.Oh they'll custom set them for you when you order them - great, how do I measure exactly what I need, guess? Then what, if it's not right, send them back? What they ought to do is sell a unit that you cna plug in and set the servo endpoints. You only need one for however many of their units you have. If your layout works with the preset default - great, you don't have to buy this extra device. Otherwise, you can order that to set them up as needed, but without the unecessary epense of having alighnment circuitry in each one. It would greatly enhance the utility of their devices.
That's my take after seeing the ad this morning and reading over what they can do.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I wondered how long before a response. A picture is usually worth a thousand words.
One thing in the manual I didn;t see ont he page, they do cut power to the servo. So maybe I take back the part about needing to adjust the throw. Although if they are monitoring the current to cut off when the throw is complete, they have the code in their controller to do an auto-calibrate. Meaning, that's how you do autocalibration, you keep increasing the throw until the current spikes, indicating that the servo couldn't complete the movement and was restrained somehow, so you back off and save the previous location. Or a bit more, to allow for any drift without getting stuck in that dreaded servo buzz mode where it's trying to reach the commanded position but can't.
Pardon me. Maybe I missed something.
What does this gadget do that I haven't been doing for decades with four-for-a-buck slide switches or ancient KTM twin-coil machines?
Chuck (Modeling Central Japan in September, 1964)
Being an ''Old Geezer'' I agree with Your statement Chuck.
Maybe it responds to verbal commands, like ''Go Go Gadget''
Frank
tomikawaTT Pardon me. Maybe I missed something. What does this gadget do that I haven't been doing for decades with four-for-a-buck slide switches or ancient KTM twin-coil machines? Chuck (Modeling Central Japan in September, 1964)
rrebell tomikawaTT Pardon me. Maybe I missed something. What does this gadget do that I haven't been doing for decades with four-for-a-buck slide switches or ancient KTM twin-coil machines? Chuck (Modeling Central Japan in September, 1964) Auto powers a frog to the right polarity for the way a switch is set without shorting out in DC. In DCC they have a frog juicer, this one works with DCC, DCC variants and DC. Much cheaper too if you need power routing for an all metal frog (dose not need to be DCC freindly).
Auto powers a frog to the right polarity for the way a switch is set without shorting out in DC. In DCC they have a frog juicer, this one works with DCC, DCC variants and DC. Much cheaper too if you need power routing for an all metal frog (dose not need to be DCC freindly).
So?
The hot frogs of my hand-laid specialwork are connected to break-before-make SPDT contacts. The frog is connected to the stock rail that has a point pressed against it - and nothing when the points are in transit. That is the same for analog DC, DCC, TCS and those early 20th century electronic control systems now dead.
Other contacts are available for signals, panel indicators and MZL power routing circuits.
If I have a really dire need for still more contacts I add a standard relay (or two, or three...)
Just to satisfy my curiosity, how many contact sets does this widget have?
Chuck (Modeling Central Japan in September, 1964 - without wonderwidgets)
The ones witht he frog power thing have 2 sets, one for the frog and one extra set. Break before make is exactly what it does, though controlled by the microcontroller and not the physical design of the contacts. There are no sensors, and you still have to wire the proper polarity to the relay or it will cause a short, just like wiring old switch machine contacts backwards. There are no sensors for automatic operation - that's the difference compared to the Frog Juicer for DCC - the Frog Juicer just sets the frog to whichever polarity doesn;t short, no guessing at which contact goes to which rail. That functionality is still something not in DC, but it isn;t really needed and I'm not a huge fan of that or autoreversers for that matter. Better to have controlled contacts and AVOID the short whenever possible, switchthe polarity before the train even gets to the gaps.
rrinker That functionality is still something not in DC, but it isn;t really needed and I'm not a huge fan of that or autoreversers for that matter. Better to have controlled contacts and AVOID the short whenever possible, switchthe polarity before the train even gets to the gaps. --Randy
That functionality is still something not in DC, but it isn;t really needed and I'm not a huge fan of that or autoreversers for that matter. Better to have controlled contacts and AVOID the short whenever possible, switchthe polarity before the train even gets to the gaps.
Randy
A man after my own heart. I have never been thrilled with deliberately causing a short circuit to start some electrical/electronic switching. Just something that rubs me wrong.
But I just get blank stares when I suggest use of Tortoise contacts instead of auto-reversers to switch the polarity of the wyes on our DCC club layout. But no - the club would rather mess with the timing of the auto-reversers and local circuit breakers than wire up contacts on an existing switch machine.
just my thoughts and experiences
Fred W
Sometimes it's unavoidable, like a turntable. Split ring pickup works great - until you have sound locos and the sound cuts out halfway through the spin. Maybe with a big enough keepalive you could have a big enough ring gap to prevent shorts yet the sound wouldn't stop over the dead spots. The only thing I've seen that worked without waiting for the short is that expensive NYRS turntable controller, it keeps track of which way the table is facing and operates a relay to match the polarity before you run the loco off the bridge track. But just the CONTROLLER costs more than the entire Walthers indexed turntable.
Wyes can be another sticking point. If it's just a turning wye, it's not a big deal, but if two or even all three legs actually are full fledged routes around the layout, not just stubs for turning, you can get an awful lot of contacts involved to make sure everything is just right.
And then there is the thing that inspired the Frog Juicer in the first place - that crazy puzzle work (entirely prototypical) on Tim Warris's CNJ Bronx Terminal layout. I wouldn;t want to try and figure out the contact logic for all possible combinations of those points, to get the frog polarity right. It was bad enough trying to figure it out on a friend's layout, where he build a double crossover with another switch through it. We could get various combinations to work, nut never every possible route, in the end I think because one frog was always in direct conflict - for the train to pass without a short, this one had to be both polarities at the same time. Eventually he removed the extra set of points and made it an ordinary double crossover, that is switch by the Tortoise contacts and works great now. The complex version was like a piece of jewelry, all hand laid, in N scale, using code 40 rail. Oh, and it was to 9mm fine scale!
ANd if the complaint is that the Tortoise contacts can't handle it (for a swtich frog - why not? It's not like you can have a dozen locos on the frog at the same time), well, you can always drive a heavy duty relay with the Torotise contacts. Still cheaper than an autoreverser.
Short circuit protection is one thing - deliberately causing a short, just seemed silly to me.
fwright rrinker That functionality is still something not in DC, but it isn;t really needed and I'm not a huge fan of that or autoreversers for that matter. Better to have controlled contacts and AVOID the short whenever possible, switchthe polarity before the train even gets to the gaps. --Randy Randy A man after my own heart. I have never been thrilled with deliberately causing a short circuit to start some electrical/electronic switching. Just something that rubs me wrong. But I just get blank stares when I suggest use of Tortoise contacts instead of auto-reversers to switch the polarity of the wyes on our DCC club layout. But no - the club would rather mess with the timing of the auto-reversers and local circuit breakers than wire up contacts on an existing switch machine. just my thoughts and experiences Fred W
Fred, how are the Tortoise contacts used to reverse polarity?
Alton Junction
richhotrain Fred, how are the Tortoise contacts used to reverse polarity? Rich
Perhaps I can do a diagram at home tonight - it'll be easier to follow.
The basic theory is to reverse the polarity of the wye tail track at the same time as you throw the turnout for the tail. The polarity of the wye tail is matched to the wye leg for which the turnout is thrown. Each rail of the reversing section (wye tail) is wired to the "center" post of a switch machine contact - it functions just like the frog feed. The contacts select which polarity will be fed to each rail of the wye tail, depending on turnout position.
The concept works fine in both DC and DCC. With DC, any locomotive in the wye tail has to be stopped when the turnout is thrown because the locomotive will reverse directions with the polarity reversal. With DCC, the turnout can be thrown with the locomotive moving.
A consequence of this wiring method is that the entire wye tail polarity is controlled by the turnout. This was seen as a drawback by the modular club as the configuration of the wye tail is always different from one setup to another. I didn't see a problem with this as long as the track bus connection at the wye tail interface always came through the switch machine contacts.
With our current system of auto-reversers for the wye tails we have 2 issues. 1) Train length can often exceed reversing section length, since tail-extending modules are wired to the normal track bus, not to the wye tail. We mitigate this somewhat by extending the reversing section as far down the wye legs as possible - usually right to the turnout at the leg base. 2) Auto-reversers have to be configured to switch polarity faster than the local circuit breaker can react which has in turn has to break the circuit faster than the booster circuit breaker can react.
The issues are certainly resolveable, no matter which solution is chosen. As an electrical engineer, I just have an aversion to deliberately causing short circuits. Short circuits, no matter how benign, are to be prevented and protected from.
I'll try to get a drawing done tonight or later this week.
Thanks, Fred, I look forward to the diagram.
richhotrain how are the Tortoise contacts used to reverse polarity?
see link, model railway wiring. Both SPDT can be used to reverse polarity to two rails
greg - Philadelphia & Reading / Reading
Doesn't this require manual action to reverse polarity though instead of an auto-reverser action?
I have had a few instances on my layout where I use the Tortoise auxiliary contacts to power the Shinohara frog and point rails. Unless the timing is perfect or if the points hang up for any reason you will get a short when the bronze tab or the point contacts the stock rail. Unless you isolate the frog at all four rails. Then you have to rely on the point contacting the stock rail to power the point rails leading to the frog.
Seems that I read somewhere that you can remove the bronze contact AND you can open up the Tortoise to make a little cut on the PC board to make the dead spot larger when the common (#4) switches between the two legs (#2&3)
I have since replaced all my mainline turnouts with all live turnouts and powered some of the frogs with the Hex Juicer.
Take care, Ed
You don't have to do both - cut the jumpers so the frog is isolated and insulate the two point rails from each other, and it won't short out. In other words - make it DCC friendly. Just isolating the frog will stop the shorting if the Tortoise contact makes before the opposite point rail comes loose. Isolating the point rails from each other will also help, but more to prevent the backs of wheels from causing a short when they touch the open point rail.
richhotrain Doesn't this require manual action to reverse polarity though instead of an auto-reverser action? Rich
No more than normal - you have to throw the turnout to back the train through the opposite leg of the wye anyway.
richhotrainDoesn't this require manual action to reverse polarity though instead of an auto-reverser action?
if you had a simple layout with a single reversing section, this might be a simple way to reverse the mainline track polarity while running your train inside the reverse loop. the mainline track polarity would always be consistent with the turnout position.
of course this would be a problem if a 2nd train we running on the main-line and you were using DC.
of course there may be a temporary loss of mainline power if you were using DCC
of course, this might not be possible on larger layouts with multiple reversing section, but there may be situations where is could avoid the need for an auto-reverser.