Dual DC/DCC frog juicer

[Donw]

Does anyone know if there is any device which will switch the frog automatically which will work on DC and DCC. I have a small layout test track using Peco points as it was intended as a test track I didn't fit any switches for the frogs. This has resulted in some problems. I have put in a switch for the worst offender but it would be simpler to use a frog juicer. However I want to be able to switch the control between DCC and DC.

Don

[Phil S]

Since there is not always any voltage on an analogue track, and its polarity is direction dependant, there is no way that it can be used, as such, to automatically switch the frog polarity.

 

However, you could look at alternative approaches - such as optical detection  - to determine which route a train is approachign the crtitical part of the crossing from, and then use that to swtich a set of relays whch control the polarity - in this way, the frog polarity can be set independant of adjacent points - because not all setttings have a preset point pattern to determine the result - especially with (my usual simple example) - of trams passing over sprung points.   But equally within an industrial shunting area which is not subject to full mainline interlocked signalling.

[RFS]

Phil S, on 29 Dec 2015 - 19:11, said:Phil S, on 29 Dec 2015 - 19:11, said:Phil S, on 29 Dec 2015 - 19:11, said:Phil S, on 29 Dec 2015 - 19:11, said:

 

However, you could look at alternative approaches - such as optical detection  - to determine which route a train is approachign the crtitical part of the crossing from, and then use that to swtich a set of relays whch control the polarity - in this way, the frog polarity can be set independant of adjacent points - because not all setttings have a preset point pattern to determine the result - especially with (my usual simple example) - of trams passing over sprung points.   But equally within an industrial shunting area which is not subject to full mainline interlocked signalling.

 

Wouldn't be simpler to just use a point motor with a reliable switch? Tortoise, Cobalt etc. both have built-in switches which can switch the rail power - DC or DCC - whatever's live at the time.

 

And BTW why does the forum software add an extra quote line every time I edit the post?

[Crosland]

Since there is not always any voltage on an analogue track, and its polarity is direction dependant, there is no way that it can be used, as such, to automatically switch the frog polarity.

 

Since frog juicers only switch when a short occurs, due to running the wrong way there will be, by definition, voltage on the track with DC running.

 

DCC is AC and switches polarity 1000s of times a second, DC just does it a bit less often

 

I see no reason a DC "frog juicer" could not be designed. Whether it's worth someones while is another matter.

[Donw]

I believe Frog Juicers have the advantage that they will also protect against a short. Having fixed the turnouts down as they were made ( thinking just of a test track) I would have to lift them to cut the links and bond the stock rails. The short protection is useful for DCC to stop the system shunting down.  I normally handlay track this was just done as a quickie . If handlaid I would have probably used Tortoises which I did before. Now I would go for Servos. I believe neither like the spring in the Peco turnouts. I was really looking for a quick easy answer.

Don

[Grovenor]

Now I would go for Servos. I believe neither like the spring in the Peco turnouts.

The Peco spring is not a problem for Servos, in fact it helps as you don't need to rely on the Servo keeping the blades tight.

See https://youtu.be/_4T8xw0ibvc and https://youtu.be/f4MGyCEL5XA

This has the Peco spring left in, the arrangement was done for someone who wanted a low profile offset drive.

You can also mount directly under the point as https://youtu.be/zcKRknQ2Hew also with the spring in place.

Regards

[RFS]

Donw, on 29 Dec 2015 - 22:58, said:

I believe Frog Juicers have the advantage that they will also protect against a short.

Don

 

If you drive a loco over a trailing turnout set against it, you will get a DCC short on the frog if it's standard Electrofrog.  However, a frog juicer will correct the polarity for you, allowing the loco to continue on to the turnout where it will derail due to the blades being set the wrong way.  This usually causes a DCC short anyway.

[Suzie]

If it is just a test track why not just stick a microswitch on the end of the tiebar? It can be carefully adjusted to switch mid-way.

 

It is fiddly but possible to cut the links and solder on a couple of droppers after the track has been laid.

[Donw]

If it is just a test track why not just stick a microswitch on the end of the tiebar? It can be carefully adjusted to switch mid-way.

 

It is fiddly but possible to cut the links and solder on a couple of droppers after the track has been laid.

 

It started as a test track but has since been ballasted and scenic work added.

thanks

Don

[298]

I believe Frog Juicers have the advantage that they will also protect against a short. Having fixed the turnouts down as they were made ( thinking just of a test track) I would have to lift them to cut the links and bond the stock rails.

Can't this be done in situ...? Even if you can't get a razor saw through the links, a slitting disc could be used to create the necessary gaps with droppers added as needed, even if this means a bit of re-ballasting.

 

Then again, I'm sure someone will be along shortly to tell you none of this is necessary, and all you need to do is spend an hour cleaning the track (incl the shiny point blades) every time you want to run a train.

[Suzie]

Are the points motorised, and if so what with?

[Crosland]

I believe Frog Juicers have the advantage that they will also protect against a short. 

 

They rely on shorts. It's the short circuit caused by running onto a wrongly switched frog that is detected by the frog juicer.

[bgman]

These are the only Christmas lights I put up this year and they won't be coming down in the new year !

 

 

Working perfectly

[bgman]

P.S. The two boards of "juicers" have been placed on a new ongoing layout. Prior to installing I test ran several locos over modified electro frog turnouts and short wheelbased locos stalled. After installing the "juicers" slow running was a dream.

[RFS]

bgman, on 30 Dec 2015 - 10:17, said:

P.S. The two boards of "juicers" have been placed on a new ongoing layout. Prior to installing I test ran several locos over modified electro frog turnouts and short wheelbased locos stalled. After installing the "juicers" slow running was a dream.

 

A frog juicer performs exactly the same function as a polarity switch, so I can't see how it improves running through a turnout unless your locos were previously stalling because there was no switch, just point blade contact.

[bgman]

A frog juicer performs exactly the same function as a polarity switch, so I can't see how it improves running through a turnout unless your locos were previously stalling because there was no switch, just point blade contact.

With respect it's an easier solution and I'm happy with it using slow acting motors, that's the way I roll !

It's what I want to use to make " playing trains" easier thank you

[Junctionmad]

No reason why the concept of automatic polarity switching of the common crossing can't be done in DC in a similar fashion to DCC frog juicers. The task is a little more complex due to lower voltages and the hence detecting the loco current

[Oakydoke]

Are the points motorised, and if so what with?

At last, an attempt to solve the problem.

In addition to Suzie's question...

...if not motorised, how are they switched?

Is there room under the test track to gain access or to install any devices?

[Mike Friedman]

And what type and scale are the Peco points you have installed?

 

And while frog juicers work on DCC (regardless of your opinion of their value compared to other solutions) they do not on DC so the poster requires another solution that will work on both. Hopefully with the minimum of disruption to the already laid points.

 

What that solution may be I don't know

[Donw]

There are several solutions.

Firstly when changing from a test track to a scenic layout it was to take it to a show with only a few weeks to get it ready. So I didn't have much time. I did bury some plastruct tubing in the ballast and ground cover from the baseboard edge to the tiebar. A piece of brass wire through the tube with the end wrapped round the knob on the tiebar gives a push pull to operate the turnouts. This fits in well with three link couplings and a hand held control with the operator walking up and down with the train. It also is a friendly way to exhibit a layout. One turnout in particular was giving poor contact on the blade so I fitted a switch next to the brass rod to back up the contact. It will work well enough. But as I intend fitting sound units using DCC I was concerned about the likelihood of getting shorts. I was hoping that someone would say ah messers xxx Juicer would work on either. It would have been an elegant solution.

Getting to the underside of the turnouts would be an issue as they are stuck down onto polystyrene sheet about 12mm thick. I was hoping someone would say messers xxxx's unti will work giving a neat elegant solution. I will probably fix more switches to the front. Or I might just decide to build another layout handlay the track and use a Megapoint controller with servos and microswitches to work the turnouts on second thoughts I probably wont have the time so perhaps struggle on as it is and add switches if I get too much trouble. 

Don