Soloniods and polarity switching.

[Aussie 3 railer]

Hello All

After several weeks of reading and watching endless U tube videoes I am totally confused over this question.

If I use the likes of Peco soloniods or others that feature frog polarity switching do I need frog juicers as well. I have just ordered several Peco unifrog points which are hard to come by here in AU at the moment.... must be popular.

I am probably like most and won't want to spend on something unnecessary if possible. So any advice here greatly appreciated.

Dirk

[Tricky Dicky]

Peco solenoids do not have a built in polarity switch unlike one of the SEEP versions, however the seep switch is not very reliable as it is basically a sprung washer bridging two of three copper tracks on a PCB and can tarnish over time giving poor contact. Peco do make a changeover switch which mounts on the motor and is activated by the movement of the actuator I cannot recall the part number someone else might.

What you need to do to wire the switch is first isolate the frog which on new points is just a couple of wires bridging two small gaps in the rails that form the crossing and then soldering two bridging wires from the stock rails to the each adjacent rail in the centre. A diagram or photo which I do not have to hand at the moment explains this better, go to Brians website and in the electrics section he has good diagrams and a thorough explanation. Or better still get hold of one of his excellent books (Brian I will notify you where to send the commission for the plug). Getting back to the switch wiring the common of the changeover switch is connected to the frog via the suppplied wire whilst the other connections are made to their respective stock rails. You also need to isolate the V rails from the two diverging tracks using insulated rail joiners. Any changeover switch will do the same job as long as it is actuated by the point movement, many people use micro switches for this if getting the Peco version is difficult.

Richard


PS you do not need juicers if using switches to change frog polarity. Juicers rely on detecting a short and quickly reacting but in DCC systems they have the potential to trip the system though most people say it is very rare but switching is the more reliable method.

[Brian]

Hi
There is at this time only a limited number of OO scale Unifrog Peco points manufactured, so this is possibly why you're experiencing issues with supply?

From the packet Unifrog work as any other Insulated frog point and do not require frog polarity switching. See here https://www.brian-lambert.co.uk/Electri ... ml#Unifrog
When converted to Live frog they will need some form of frog polarity switching.
This can be a SPDT slide switch which can often operate the point too.
A micro switch fitted to one side of the point so as the moving stretcher bar operates the micro switches lever. Often used with surface mounting solenoid motors such as the Peco PL-11 etc
A solenoid point motor with an additional change-over switch fitted such as the Peco PL10 with PL-13 or PL-15 switch fitted. Or a Seep PM1 with the basic change over switch already on board.
If DCC traction operation (NOT DC) then a Frog Juicer can be used instead of a switch. Note these Juicers rely on a momentary short circuit occurring in the points frog area to flip over the DCC polarity. These cannot be used on DC (Analogue layouts).

You would not use a switch and a frog juicer for frog polarity switching. However, there is no reason why both cannot be fitted to a point. On a DCC layout the Juicer providing the automatic frog polarity while the switch provides some other circuit switching. such as possibly Panel indication Signal control etc

Whether switch or frog juicer they are basically all wired the same - One connection goes to the frog wire then two other connections connect to the point outer stock rails or the DCC bus pair which must be wired the correct way around or you will get a short circuit if wrong!

[Aussie 3 railer]

Looks like I'll be saving a $ or two here by not using frog juicers. I was just begining to think this was going to cost a bundle and how I was going to explain all the ongoings to the bride......

Thanks again for the input gents it is certainly appreciated.

Dirk

[Aussie 3 railer]

Morning Brian,

Your diagrams are a massive help thank you.

Just a question here about CDU'S. I found these ones, attached, and look similar to the ones in your diagram. Would these be enough to power 7 points.

Are AC CDU's the same as DC CDU's.

Dirk

[Aussie 3 railer]

Meant to add to the above..... I wasn't planning on powering all 7 at once.

Ditk

[Rog (RJ)]

It doesn't really matter how many point motors are on the layout because they only take any power while they are being operated, so that CDU would be suitable for 1 or 2 at a time.

[Brian]

As Rog(RJ) says, conventionally one or two solenoids are moved only at any one time, so the CDU is fine.
I would use 16/0.2mm (0.5mm2 or 20AWG) wire throughout

However, and for all forum readers too, some modellers use what is called "Route Setting" where six or more solenoids all move together to set up a complete route all in one go. This is usually done with the aid of a diode matrix and then a much larger CDU capacitance is needed together with a large return wire - 32/0.2mm approx. (1.0mm2 or 17AWG).

[Aussie 3 railer]

Thank you everyone for the help. I think I am finally sorting the wheat from chaff.

Dirk

[bulleidboy]

Peco do sell a polarity switch which attaches neatly to the point motor. Although I have just replaced my Peco motors for slow-action motors, the Peco motors with the polarity switch worked well for ten years.