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I think I was very, very silly on my last layout. I had electrofrog points - but didn't do any wiring for the frogs. I had PM1 point motors as I was expecting to wire up the frogs - but it all worked in DC without doing it. Is the wiring only needed for DCC or should I have done it for better running?
 

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There are two reasons for wiring the frogs separately

1) You are no longer relying on either the pressure of the switch blade or the little wiper underneath it to provide the power to the frog. This make running through the point more reliable in the longer term.

2) Once you stop using the switch blades to carry the power, they can be isolated from the frog and permanently bonded to their neighbouring running rail. This means you remove the risk of shorts caused by metal wheels passing through the gap between the switch blade and the fixed running rail. Even momentary shorts on DCC are a "bad thing" because they will shut the system down. On DC a momentary short will go un-noticed.

It is not a good idea to power the frog via a switch on the motor and retain power routing through the switch blades. You cannot guarantee that both power routes will switch at the same time, so you are quite likely to get shorts each time you change the points which is not what you want on DCC.

David
 

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Discussion Starter · #3 ·
QUOTE (dwb @ 25 Oct 2008, 17:52) <{POST_SNAPBACK}>There are two reasons for wiring the frogs separately

1) You are no longer relying on either the pressure of the switch blade or the little wiper underneath it to provide the power to the frog. This make running through the point more reliable in the longer term.

2) Once you stop using the switch blades to carry the power, they can be isolated from the frog and permanently bonded to their neighbouring running rail. This means you remove the risk of shorts caused by metal wheels passing through the gap between the switch blade and the fixed running rail. Even momentary shorts on DCC are a "bad thing" because they will shut the system down. On DC a momentary short will go un-noticed.

It is not a good idea to power the frog via a switch on the motor and retain power routing through the switch blades. You cannot guarantee that both power routes will switch at the same time, so you are quite likely to get shorts each time you change the points which is not what you want on DCC.

David

Thanks David - it all becomes clear why I was having such unreliable running through points!

I'm a bit of a novice - as I'm running DC should I be concerned with isolating the switch blades? If so, how do I do it?
 

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QUOTE I'm a bit of a novice - as I'm running DC should I be concerned with isolating the switch blades? If so, how do I do it?

If you are going to motorise your electrofrog points and you don't mind the extra cost of the switches then you may as well go the whole way and isolate the switch blades from the frog and bond them permanently to the adjacent running rails. Instructions for how to do this on Peco OO points come on the leaflet in the box. I expect that the same is true for N? So if you haven't thrown away every single example of the identical instruction sheets which came with your points, you have your guide. If you have recycled those sheets, we'll have to wait for an N gauge user to come along to offer some help because I don't know the details of the underside of the points you have.

For DC without motorised points I would probably stick with frog switching via the blades.

David
 

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As an N gauge user I'm not totally familiar with how this works in OO, but I believe the "easy" way of doing this in OO is not provided in N. All the suggestions I've seen relating to Peco N gauge involve cutting the rails between the frog and the blades with a slitting disc or similar.

Not being very keen on these suggestions I have done just what isn't recommended above - wiring the frogs through an auxiliary switch but leaving the blades to conduct as well. In my case this is the Seep auxiliary switch which is mechanically linked to the tiebar. I've never had any problems with short circuits either due to the frog polarity switching out of synch with the blades, or from wheels shorting between the switch blade and the stock rail (unless the train is already derailed!). I think we have the grossly overscale switch gap on the Peco points to thank for this - and it might not still be true if I ran older (coarser) wheels or steam locos with long fixed wheelbases.

The Seep motor switch isn't very reliable and takes careful setting up otherwise it causes short circuits itself, but that has nothing to do with the lack of isolation in the points.
 

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QUOTE I've never had any problems with short circuits either due to the frog polarity switching out of synch with the blades...
The Seep motor switch isn't very reliable and takes careful setting up otherwise it causes short circuits itself

I use Fulgurex motors which have auxiliary micro switches. These switch over abruptly and at a different time to the point blades themselves.

Are you using DCC Edwin? I can't remember whether you've said so in the past.

David
 

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QUOTE (dwb @ 25 Oct 2008, 22:52) <{POST_SNAPBACK}>I use Fulgurex motors which have auxiliary micro switches. These switch over abruptly and at a different time to the point blades themselves.

Are you using DCC Edwin? I can't remember whether you've said so in the past.

David

Yes I do use DCC.
 

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QUOTE Yes I do use DCC.

Thanks for the clarification. On your experience I'd say the Seep motor / switch combo is good to go without the mods which is really useful for N given you don't get the "handy" removable links that come on the OO version.

I'm guessing there aren't any wipers on the switch blades in N then? I'd expect them to reduce the margin for error on switching?

David
 

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QUOTE (Edwin @ 25 Oct 2008, 20:33) <{POST_SNAPBACK}>The Seep motor switch isn't very reliable and takes careful setting up otherwise it causes short circuits itself, but that has nothing to do with the lack of isolation in the points.

Can I just ask, do you mean PM1 point motors? I've recently bought PM1s for my layout - I bought them for the ability to switch the frog polarity. I've added jumper wires and cut and filled the rails.

I'm using the diagram in post 10 on this thread. http://www.modelrailforum.com/forums/index...?showtopic=6006
 

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QUOTE (eddscott @ 26 Oct 2008, 11:42) <{POST_SNAPBACK}>Can I just ask, do you mean PM1 point motors? I've recently bought PM1s for my layout - I bought them for the ability to switch the frog polarity. I've added jumper wires and cut and filled the rails.

I'm using the diagram in post 10 on this thread. http://www.modelrailforum.com/forums/index...?showtopic=6006

Yes this is the PM1. The switch comprises a brass washer that slides over PCB tracks. If the motor is displaced slightly parallel to the rails then the washer can touch both tracks at once causing a short circuit. If the motor is displaced perpendicular to the rail then the washer may be open circuit in one point setting. Either can be remedied by careful bending of the actuator rod. Even so it sometimes doesn't conduct at all, possibly corrosion of the brass as it seems to happen when the point has not been used in that setting for a while.
 

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I have some Seep PM2 point motors can I use them with Peco 75 electrofrog points? do i need a seperate switch ? if yes what kind ? or can I wire in an automatic switch as I throw the point motor??

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