Peco unifrog question

[Jamesb]

Hi all,

 

Im currently in the process of building my first layout in over 10 years. I'm new to Dcc but think I've mastered the basics. I have a quick question though regarding wiring Peco unifrog points. I understand that they are wired as per normal electrofrog/insulfrog points (ie at the toe). My question might seem like a completely daft one, but I'd appreciate any help. In this scenario pictured below, do I require a single pair of droppers at point (A) which will feed both points or do I need an additional pair of droppers at (B) as well?

 

Thanks, James.

[rob D2]

You don’t , but you are relying on all the juice getting through point A and feeding B,

 

I did this but eventually put a second power feed in for reliability at B 

[Michael Hodgson]

As I understood it (not yet having used one) the frogs themselves are isolated from the rest of the point and are electrically dead unless you do something positive about connecting them via some form of changeover switch?

[rob D2]

Correct , but his query doesn’t relate to that but feeds .

 

the whole frog is isolated unless you wire it up to something - mine are wired to the frog feed from cobalt DCC point motors which are simple to install and use 

[dasatcopthorne]

So. If you are using metal fishplates then you will get connection all the way.

But!

It would be much safer and worthwhile to put feeds into all turnouts

 

After all, it's only a few more wires.

 

Don't scrimp.

 

Dave

[Jamesb]

Many thanks for the replies. This makes sense. 

 

James.

[griffgriff]

Good practice dictates every rail should have a dropper. You shouldn’t rely on fishplates alone with DCC. Potential power draw can be heavy and any heat created can prove to be disastrous. 
 

Griff

[RobinofLoxley]

On 27/09/2020 at 17:59, griffgriff said:

Good practice dictates every rail should have a dropper. You shouldn’t rely on fishplates alone with DCC. Potential power draw can be heavy and any heat created can prove to be disastrous. 
 

Griff

Woud you consider droppers soldered to fishplates adequate?

[WIMorrison]

No, that is same as just using railjoiners, the power is being transferred to the rails by the push connection of the rail joiner, bad idea to rely on them

[DCB]

If you are using sound/ lights on stock on these roads  then you need the B droppers and also droppers on the bottom points frog ends as well.    Its not because its DCC you need the droppers but the power, 4 to 6 amps DC will cause the same problems, limit your DCC power to 1 amp and most of the need for modified points and droppers will disappear like Politicians when faced with an awkward question.

[Pete the Elaner]

On 27/09/2020 at 17:59, griffgriff said:

Good practice dictates every rail should have a dropper. You shouldn’t rely on fishplates alone with DCC. Potential power draw can be heavy and any heat created can prove to be disastrous. 
 

Griff

 

They are also a weak connection.

Since the rails & joiners are a friction fit, paint, water & glue can help to add resistance to the join, especially after a few years when resistive oxidation products have had a chance to build up.

A voltage is required to push a current across a resistance & with DC, you want low voltages for slow running delivered across the motor as efficiently as possible, not wasted across a rail joint.

[Nigelcliffe]

A wire soldered to fishplate isn't optimal.  But its probably better than a badly soldered wire to a rail, which with poor technique is often a dry joint.    I'd say for a smaller layout, and perhaps one which isn't intended to have a long life, the fishplate might be fine.  

 

Whether the fishplate method is reliable in the medium to longer term will depend on the other factors, some of those mentioned by Pete immediately above this posting.     Its a bit like relying on the contacts on Peco point blades; they're not perfect, but they do work for many people and can work for decades without an issue.    But, just like the point blade contact, the fishplate might become iffy in its contact and give running problems.    So, the wiring perfectionist will work around both the blade contact and fishplate contact, coming up with better engineering solutions.  

 

( Or could just go to battery and wireless/radio control, then no track to wire whatsoever ! ).  

 

- Nigel