Frog Juicers compatible with RailPro?

[JJ Crooke]

I was wondering if anyone knew for sure or, better yet, actually tried using the Tam Valley's mono or hex Frog Juicers to power the frogs on their layout. Tam Valley's website specifies the Frog Juicers are DCC devices only but I'm a bit confused knowing that you can run RailPro equipped locomotives on DCC layouts. I have not powered-up my layout yet (not quite ready) but I just realized that they may not be compatible with the PWR-56. I've already wired two mono Frog Juicers on my layout.

Better to find out now if it is an issue than finding out the hard way when I power-up my layout for the first time. 

[melarson]

There does seem to be a lot of confusion on the topic of inter-mixing RP and DCC control systems.  The fact is, as control systems they don't inter-mix.  No device that requires a DCC signal (reversers, juicers, some occupancy detectors, etc) will work on a RailPro-powered layout.  DCC devices that don't require the signal (a few occupancy detectors come to mind) may or may not work on RP, but the device manufacturer must state that it will work on DC systems for them to be RP-compatible.  Of course, going the other way, Ring states clearly that their devices (AR-1, etc) are not DCC compatible.

But we can run RailPro-equipped engines on a DCC-powered layout because the modules (LM-2/LM-2S) are able to use the DCC track power as their power supply, in lieu of pure DC.  This is accomplished on the modules by using a rectifier/filter/regulator circuit at the inputs (red and black wires).  In fact, DCC decoders do the same thing to supply power to their on-board circuitry.  Unlike decoders however, the RP modules ignore the data stream that the DCC system puts on the track and just uses the power.

Apparently the frog juicers need that DCC data stream (or more accurately, that waveform) to work.  I don't know if they will be damaged if you power them with pure DC, but given that they won't work on pure DC, thus making them useless for a RailPro-powered layout, why take the chance?

[William Brillinger]

Why is the DCC signal required? This makes no sense to me. Aren't these kinds of devices simply electronic switches that detect shorts etc?

I'm sure they don't work on DC layouts merely because the locomotives are not isolated from the direct track power.

Has anybody actually asked TamValley if they will work with RailPro?

Tam's website says:
Q: I sometimes operate my DCC layout as DC.  I know they will not work with DC but will this hurt my frog juicers?
A: A lot of model railroaders have done this and it has not caused any damage.  However, I can't warranty your frog juicers in this case.

So probably no harm in trying it.

[JJ Crooke]

Thanks for the replies. Because of the relatively low cost of a mono Frog Juicer (less than $20 CAD), I may take a chance and try to power one with the PWR-56. But I won't get my hopes up. Tam Valley's "DCC only" claim could be for warranty purposes only but I will send them an email to find out, although Tam will most likely stick to its 'DCC only" claim even though the juicers could technically work with DC.

That being said, does anyone knows of an alternative to power turnout frogs (e.g. DC compatible frog juicer, Tortoise type switch machine) that would work with the PWR-56? I will have to do more research on this.

[G8B4Life]

The "DCC only" part for the waveform could be on the track side; it might not be able to detect and switch properly if it see's a constant +v or a constant 0v. The power supply side get's rectified as soon as it enters the board (all those components don't work on AC) so the PWR-56 should work on powering it up. Whether it would switch frog power correctly though who knows.

Edit: On the bottom of Tams website it says this.

"Will DC damage the frog juicer?  No- although they will not power the frogs, they will not be damaged by DC so feel free to run your layout in DC mode with the frog juicers attached." which gives some weight to the above theory, or similar theory anyway.

What switch machines are you using Joel? Although you said "Tortoise like" Tortoise can apparently switch frog polarity.

As to what else is out there, well all I can really say is research research research, because I don't know. I have one of these. Mine is an older version of A004 set (without DCC the set would be A002). These are of course complete turnout control sets but they are made for DC in the first instance.

http://www.anemodel.com/products_list.aspx?LEVEL=1&TYPE=2

- Tim

[JJ Crooke]

Tim, I am not using any switch machines besides the Frog Juicers for frog polarity. My turnouts are Peco Code 83 Electrofrog, all manually hand-thrown. I wanted to avoid using any kind of switch machines but I may not have a choice, we'll see. The SmartSwitch is an interesting option although a bit expensive but I'll look more into it. Either way, it will most likely be an expensive alternate option (whatever that may be) if the Frog Juicers don't work.

My layout is all wired but I haven't installed any LM-2S in my locomotives yet so it may take me another couple of weeks before I'm ready to test the Frog Juicers with the PWR-56. Stay tuned....

[William Brillinger]

I have a hand thrown solution: http://pdc.ca/rr/catalog/product/simple-switch-machine/53

[drisdon]

I had the same problem, but I see Bills machine is the perfect and affordable solution.  Can this be used on a module where it needs to be actuated from either side of the module?

I'll be selling my hex frog juicers next!

First Digitrax was sold, then all my decoders, Railpro just makes it all fun again.

Dan

[William Brillinger]

Yes, the simple switch machine can be actuated from both sides.

[G8B4Life]

Joel,

If your not using switch machines and throw your points manually from the edge of the layout then I can certainly recommend something like Bill's creation with a slide switch incorporated to change frog polarity, simple and proven method by thousands of layouts.

Some further investigation shows that ANE do have just the frog changing board separately, which might be better a better option if you throw the points directly by hand, and certainly less expensive that having to go the whole outfit of having switch machines.

http://anemodel.com/products_content.aspx?id=32

The manual for the board can be found in their downloads section (link at bottom of their webpage). I've not got one nor used one so I can't
comment on how good it is but it's another research avenue for you.

- Tim

[JJ Crooke]

Thank you very much for the info. Ane's SmartFrog v5 is exactly what I would need if I can't use Tam Valley's Frog Juicers with the PWR-56. I throw the points directly by hand but Bill's Simple Switch Machine is an interesting option.

[Prostreetamx]

Just returned from a train show in Costa Mesa California. There was one club layout that manually controlled all their track switches with mini slide switches built into the ground level of the track with the top of the slide switch exposed. They could move the slide switch or the points with their fingers to switch. The points and slide switch were connected with a piece of piano wire, The slide switch would change the frog polarity with no other linkage. Personally I use manually controlled bullfrog turnout controls with a built in slide switch.

[Alan]

For your consideration... A subject not often discussed with frog juicers is their mode of operation. The design essence is a) allow the problem occur; b) solve the problem as quickly as possible. A better design approach is a) prevent the problem from occurring.

Frog juicers by design purposely introduce track/wheel arcing albeit a minuscule amount but an amount nonetheless. An actual short circuit (momentary excessive high amperage induced voltage drop) must occur to trigger the juicer, i.e., allow the problem to occur. For the tiniest fraction of a second there is 50,000°F plasma at the track wheel interface. Frog juicer circuity is designed to be very fast so the arc time is very short thus minimizing the damage. Additionally, frog juicers are typically placed near the frog and connected with shorter smaller wire gauges. As a result there is virtually no capacitance to the wiring which helps minimize arc current flow.

Switched frog polarity, which is arc-free under normal conditions, has the potential for the same and perhaps even more damaging problem when a loco runs a switch. In this scenario the system or district circuit breaker extinguishes the short circuit. A system breaker will trip much slower than a frog juicer can switch polarity. System power wiring is much longer and heavier gauge wire. It will have a significant capacitance. When the loco runs a switch the arc will be longer duration (breaker trip time) and more intense (wire capacitance discharge). Running a switch is operator error and so is within human control.

So it can be said that neither frog juicers nor switched frogs genuinely achieve the ideal design: a) prevent the problem from occurring. The real difference is frequency of occurrence. Frog juicers will introduce very frequent but less intense arcing. Switched frogs will introduce infrequent but intense arcing.

It all boils down to a single question - How good are your operators?

I am of the opinion it is better to not deliberately design in a problem. Hence why I am not a fan of frog juicers. They are convenient, easy to install, virtually plug-n-play. These attributes have value. But over the long haul the layout could aptly be named Sparky! Good operators can run a switched frog layout without arcing. Or at the very least, an absolute minimum number of occurrences.

If you are as anal about preventing arcing as I am there is a solution. Switched frogs with "wrong-way sensing". This is the path I have taken. The frog polarity is controlled by the switch motor. IR sensors on the through and diverging routes sense presence of equipment. If the switch is thrown reverse of a sensed occupancy the frog polarity to the switch machine is reversed for the duration of the sensed occupancy. The to-the-switch-machine part is important. The switch machine does not attempt to align the point rails to accommodate the wrong way approaching equipment. The switch machine is too slow for that to be viable. The operator is still going to run the switch. The only difference is the frog will be the correct polarity and no arcing occurs. Once both route sensors report the switch is clear the frog returns to the polarity dictated by points position.
 

   

[JJ Crooke]

Hi everyone,

I had the chance to go down in my basement to work on my layout this past weekend for the first time in several months so I'd like to give a quick update on Tam Valley's Frog Juicers compatibility with RailPro. I was able to install an LM-2S decoder in one of my locomotive and the verdict is...

Tam Valley's Frog Juicers are NOT compatible with RailPro's PWR-56. The locomotive can run fine in one of the turnout's alignment but will create a short on the alternate alignment. The Frog Juicers will not change the polarity of the frog as it can't detect the short.

Oh well... I'll have to sell my Frog Juicers and look at the other options listed in this thread. 

[KPack]

Thanks for the info Joel.  Now we know for certain that they will not work, which is useful knowledge to all of us.

-Kevin