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Model Railroading > HO turnouts?


Date: 01/29/12 08:47
HO turnouts?
Author: john7968

What is the difference between :

DCC friendly
Insulated frog
Insulfrog

Thx
John

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Date: 01/29/12 12:45
Re: HO turnouts?
Author: pmack

John, I've never figured out what exactly makes a turnout DCC friendly. I built a layout of Mullan Pass in college and used Atlas switches. When I converted to DCC they still worked just fine. My current "layout" uses a combination of Atlas, Micro Engineering and Central Valley. They all work equally well in DC and DCC.

Now that I think about it, a couple of the Atlas switches would produce very momentary shorts as the train went through the frog. The back of the wheel would touch the opposite rail. In DC it didn't matter much but slow speeds and sensitive circuit breakers would stop the train on DCC. The fix was a little sanding and a coat of Dullcoat over the rail where the short happened. I fixed that years ago and haven't had any trouble since.

Insulfrog is Peco's name for an insulated frog. That means the frog, the part where the rails cross in a turnout, is electrically isolated from the rest of the rails. Often the frog is then powered from auxiliary contacts on a switch machine. Depending on the turnout position, the frog needs to have the same polarity as the north or south rail.



Date: 01/29/12 14:33
Re: HO turnouts?
Author: ATSF429

In DCC friendly basically the points are at the same polority as the rail they are adjacent to so you do not get shorts. Generally the frogs are isolated. In power routing switches, this points become the polarity of the opposite rail that is in contact with the power rail. If this makes sents to you. This is especially true when turnouts follow curves. The so called non DCC friendly will work on DCC but one needs to be csrefull.



Edited 2 time(s). Last edit at 01/29/12 14:39 by ATSF429.



Date: 01/30/12 17:46
Re: HO turnouts?
Author: swsf

pmack Wrote:
> Insulfrog is Peco's name for an insulated frog.
> That means the frog, the part where the rails
> cross in a turnout, is electrically isolated from
> the rest of the rails. Often the frog is then
> powered from auxiliary contacts on a switch
> machine. Depending on the turnout position, the
> frog needs to have the same polarity as the north
> or south rail.

An Insulfrog turnout will have the two frog rails insulated at the point where they would normally contact each other, which is at the pointed end of these frog rails. There is a thin plastic spacer cast in between the rails where they almost touch. The problem with this arrangement is that wide metal wheels can accidentally touch the other rail, creating a momentary short. The point rail and the continuing frog rail are electrically joined.

An Electrofrog turnout will not have the two point rails insulated from each other. Rather, they are electrically joined, and also joined to the rails that continue towards the points. There is a thin wire attached to the frog assembly to provide electrical power utilizing a device to switch the polarity as necessary, such as the contacts built into a Tortoise switch motor, or a FrogJuicer DCC polarity reverser. This would then power the frog, and all rails connected to it, including the point rails. However, the point rails are connected to the frog rails utilizing a thin jumper wire. This jumper can be snipped off to completely isolate the frog from the point rails, a very nice feature. There is also a gap in the webbing under the rails to provide a place to solder a jumper wire across the stock rails and the point rails, increasing the electrical reliability tremendously since electrical continuity is no longer dependent on how good the metal to metal contact is between the tip of the point rail and the stock rail it contacts when thrown. I personally much prefer the Electrofrog version.

See this web site for a pretty good overview of both the Insulfrog and Electorfrog turnouts and how to improve their reliability as described above.

http://www.wiringfordcc.com/switches_peco.htm



Edited 2 time(s). Last edit at 01/30/12 17:49 by swsf.



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