Points shorting with DCC and Electrofrog

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axis512
Posts: 7
Joined: Tue Nov 16, 2010 8:23 pm

Points shorting with DCC and Electrofrog

Postby axis512 » Mon Feb 28, 2011 9:34 am

Hi there,

Really hope someone can help as I am well and truly stuck :o(

Here's the problem: I have two points facing each other (sorry, don't know the official term for this - hopefully my attcahed pic should help explain?)

Points are electrofrog with DCC modifications made as suggested by Graham Plowman.

Motors are Cobalts.

Point B is fine, but everytime a loco goes over Point A, a short occurs.

Hopefully my wiring diagram makes sense. Now I am in the process of building a mimic board for switch control and installing an accessory bus powered from a 12v laptop type power source.Therefore my point motors are not currently powered via a bus and I am changing the point via a 9v batterey with two wires attached touching them to the motor to activate (i only have these two installed thus far).

The wire from the frog for Point A is attached to the motor but the wire from the frog on Point B is not. Although, Point B runs fine, but Point A short everytime.

I really don't know what I have done or am doing wrong. this is a real setback in what was a quite exciting period of elctrical success.

One other issue is that a new Bachmann class 08 stalls on the working point B also whereas all other trains don't - is this due to not enough pick up wheels?

Really sorry for rambling, but hope my attcahed pic helps make clear what i mean.

Thanks in advance for you help.
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Flashbang
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Re: Points shorting with DCC and Electrofrog

Postby Flashbang » Mon Feb 28, 2011 10:37 am

Hi
If your drawing actually reflects the wiring and the green wires are the frog feeds then....
On point 'A" the Green wire needs to connect to one of the two the frog rails (Point side of the IRJs). Not to the red powered rail as shown.

BTW the points are called a Cross-over pair. :D


Edit to correct error.
Last edited by Flashbang on Tue Mar 01, 2011 4:55 pm, edited 1 time in total.
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Broken? It was working correctly when I left it.

Rejohnson
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Re: Points shorting with DCC and Electrofrog

Postby Rejohnson » Tue Mar 01, 2011 3:34 pm

Hi

The basic wiring diagram for a peco electrofrog point and cobalt is clearly shown in the cobalt manual that can be found here.

http://www.dccconcepts.com/PDF_Download ... ctions.pdf

You will of course need the isolation gaps between the two points of the crossover, but just repeat this diagram for both.

The Cobalt switch will change the frog oplarity to match the appropriate rail if you do it right. It is of course necessary to have the frogs wires opposite to each other - in otherwords blue rail would go to terminal one on one, terminal 2 on the other.... you should wire the frog in both points

If you get a short then swap the two wires to the track over at the cobalt terminals (terminal 1 and 2).

Stalling - if you do not have one frog wired up, you will have a dead area.

regards

Richard

gppsoftware
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Re: Points shorting with DCC and Electrofrog

Postby gppsoftware » Tue Mar 22, 2011 11:31 pm

I should add a note of caution here: my advice does not describe wiring a turnout as per that diagram.
I advocate isolating the common crossing from the switch rails: http://www.mrol.com.au/Articles/Electrical/LiveFrogWiring.aspx

Graham Plowman

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Silver Surfer
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Re: Points shorting with DCC and Electrofrog

Postby Silver Surfer » Wed Mar 23, 2011 8:19 am

Rejohnson wrote:Hi
The Cobalt switch will change the frog oplarity to match the appropriate rail if you do it right. It is of course necessary to have the frogs wires opposite to each other - in otherwords blue rail would go to terminal one on one, terminal 2 on the other.... you should wire the frog in both points

If you get a short then swap the two wires to the track over at the cobalt terminals (terminal 1 and 2).

Don't think you'll get far if you wire up to terminal 1 & 2.

2&3 are outputs for one of the switches with 4 being the input to that switch. Similarly 7&8 are outputs with 5 the input for the second switch. Therefore, if using one of the Cobalt switches to change frog polarity you need 4 to go to the frog and 2&3 to the track (Or you could use 5 coupled with 7&8).

If you're getting a short it is no doubt you've inadvertantly connected 2&3 (or 7&8) to the wrong rails - swap them over to see if it rectifies the problem.

Mike

PS. Incidentally, terminals 1 & 8 are the power inputs to operate the point.

EDIT: On further thought (assuming A is the left point on your diagram and B the right) If point B is working okay but has no wire connected to the frog it raises the question of where the power is coming from? In theory your train should stop as soon as it reaches the dead frog rails - I suspect you have made a mistake with your wiring somewhere as something is clearly providing power to the point frog. Try running a train through both points set straight ahead to see if you get any shorts or if it stops, and let us know.

Also, have a look at this thread which shows some pictures of how to modify an electrofrog point - http://www.newrailwaymodellers.co.uk/Forums/viewtopic.php?f=27&t=30680&st=0&sk=t&sd=a&start=15
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Bigmet
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Re: Points shorting with DCC and Electrofrog

Postby Bigmet » Wed Mar 23, 2011 10:00 am

axis512 wrote:Hi there,
...One other issue is that a new Bachmann class 08 stalls on the working point B also whereas all other trains don't - is this due to not enough pick up wheels?...

Plenty of good advice on the points issue so lets deal with this one. This model comes fitted with wiper pick up on all wheels, and that's all the wheels it has got, so we have to make the best of it!

As far as I am concerned, job 1 with any new model is to check that the wipers all make positive contact with the wheelbacks whatever the wheel position, and are clean and grease free. (It bears saying that in my experience even quite expensive product from top end HO RTR makers can be found with the pick up not perfoming optimally. Just too much of a fiddle for the assembly workers to make perfect every time, and lubricant can leak onto wheelbacks after the loco has left the factory.) Once every wiper is making good contact on a clean surface, give it an hours running, this will polish up the contact paths nicely.

Now to the real advantage the Bachmann 08 has: a sprung centre axle. This is potentially a big help in ensuring pick up reliability, but it needs to be freed up. Take the keeper plate off, and file a recess 0.5 mm deep to allow the centre axle to drop a little further under the spring action.


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