DCC electro clips/points potential hazard?

[rob_brewer]

Good Evening

I have an issue occur today which I would like share

I operate railmaster with e link using windows 8.1 revision railmaster 1.61 (2)

On starting up system everything seemed fine.Railmaster went through its normal procedure and I went ahead to start the locos but no response.There were no problem messages/short circuit alerts.I unplugged e link having closed down railmaster as usual and removed usb.On rebooting again everything seemed OK no porblem messages but again the locos wold not respond.At this time I began to smell an electrical burning smell so quickly checked my electrical radiator elink socket etc no joy.Thinking one of the decoders was burning up perhaps I felt each loco but nothing,The smell got stronger and I was getting concerned and more puzzled.As I was toching each loco or heat my hand moved over a point which was red hot and the frog plastic had melted about 1 inch long.I quickly removed plug.On examining the point the lastic had melted by the dcc electro clip.Both point and clip had been at a high heat point as the had turned the metal discolured brown.This point along with my other are manual no motors,On checking all points 2 more were starting to melt but only slightly and in a very short time this all took place.

I took the point to my local hobby shop in Faversham and he said he had never seen anything like it and it must have been subjected to some heat to burnish the metal.The owner kindly rplaced the point free of charge and said he would take it up with Hornby rep on next visit.I have replaced all electro clips on the affected points restarted and no issues but keeping a close eye on everthing,

My view was something causing a short but I cannot find anything near or under the melted point or the others slightly affected,Also these points were not near the power inlet where I have other points which show no sign of this issue

Has anyone got any thoughts a similar problem.I stumped my local hobby shop owner as well.I must say though how grateful I am for his generosity it pays to use a local man rather than a big concern sometimes,

Im not saying its Railmaster Elink or points or dcc clips Im just baffled and a bit concerned to say the least

Rob Brewer

[37lover]

Rob,

Go have a look in the DCC section for a thread called Melting Points, it's now on the third page. John [Yelrow] will be relieved to see another User having this problem but unfortunately I don't think a solution was ever found.

[37lover]

I've just bumped the thread in the DCC section so it will be near the top now.

[Yelrow]

ROB, hi, it is i , that had the melting points problem, unwired all points, turntable, etc, and stopped it, but have never found out why. We firstly blamed a reverse polarity, in the turntable, but you have not gor one of them. We then . blamed the point decoders/ motor, but again, you have not got them. Are you running elink with 1 amp or 4 amp transformer, mine is 4 amp. The only other clue is that all my affected points were fixed net to another, eg crossing tracks. Are yours the same. What are your point numbers. I would dearly love a solution, as have NO electric points, or Turntable at present, and it may be, i blamed them unfairly. The other thing was, no short was thrown up by Railmaster. I have 6 points, 3x2, that were all affected. john 

[tony_forward]

I do not use the point clips so beloved of others... 

All my points are peco, and all have the running rails soldered to the turn rail underneath in the space provided. 

I am wondering whether the point clips are possibly not quite tight enough and the continual 'sparking' is what is generating the heat? 

Could well be barking up the wrong tree, but my layout has been running almost continuously for 2 days in preparation for the exhibition in a couple of weeks with no problems ...

[Yelrow]

Tony, are hornby points the same, do they have same facility. Cant check, without removing from layout. john

[tony_forward]

Sorry John, I don't know as I don't have any Hornby points. 

I found that older stock derailed over them so changed to Peco a couple of years ago and now have only Peco track. 

if you google 'wiring peco points' there is a video about live frog points, but the bit I solder is clearly shown Before the video starts.

[Fishmanoz]

John, Hornby points being insulfrog do not have the same soldering facility as Peco electrofrog which are quite different.

 

Back to the melting problem, there must be a low resistance causing a high current flow for this to happen.  I would be double and triple checking the layout for a short.

[tony_forward]

My peco points are insulfrog too Fishy, but the principle of the solder point is the same

[walkingthedog]

John, Hornby points being insulfrog do not have the same soldering facility as Peco electrofrog which are quite different.

 

Back to the melting problem, there must be a low resistance causing a high current flow for this to happen.  I would be double and triple checking the layout for a short.

 

 Wouldn't it be caused by high resistance where the clips are joined to the track. Similar to the rare occasion where a fishplate gets warm.  It's strange it only happens where the clips are, it has to be them. 

 

[poliss]

The 'ahem' points where the clips are attached could be dirty, causing high resistance. If there's a short the controller should cut out immediately. Try putting a coin across the rails to see if it does.

I think we worked out that John had two controllers coming into play which doubled the power going through the track and therefore causing the melting at the point clips.

[Yelrow]

Poliss, hi, thanks. I have only ever had one controller, at the time, the elink. When i clicked on the Turntable bridge, i belive the theory was that the polarity, could be wrong,, and that may have helped, but there was just the elink, controling the lot. I would add, that i have just removed 2 points to look at, and the clips, move quite happily, which suggests to me, a faulty packet of clips. john

[Yelrow]

WTD, see above, the clips are not tight. My french mate has emailed me a picture of his hornby points. He has removed tiny pieces  plastic under point, to make a path, and soldered wires into place, to take the place of the clip. He has  soldered the wires. to base of rail, making a solid joint. Can anyone see  a problem with that system. john

[tony_forward]

WTD, see above, the clips are not tight. My french mate has emailed me a picture of his hornby points. He has removed tiny pieces  plastic under point, to make a path, and soldered wires into place, to take the place of the clip. He has  soldered the wires. to base of rail, making a solid joint. Can anyone see  a problem with that system. john

 

 John, that is exactly what I said in my post earlier!

great minds think alike

[walkingthedog]

That us exactly the correct thing to do. Get rid of the clips and replace with soldered wired. 

[Yelrow]

Tony, thats what i thought, you will need to be a bit careful though, as   some of those here, are anti french, and wont accept they have great minds. You should see his two helixs, cost hom the top of a finger, but superb construction. john

[walkingthedog]

To be honest John that's what Peco have been doing for ages. As for the French having great minds, years before Concorde, Sud Aviation designed a Super Caravelle and guess what it looked like? 

[tony_forward]

Oi you lot, back to the topic please, my Easter eggs are melting!

[Yelrow]

Lucky you, no such luck in france, Lindt choc Rabbits, no filling, how we miss cadbury cream eggs. john

[tony_forward]

Cadburys creme eggs are being laid by miniature chocolate chickens these days - they're tiny!

- N gauge eggs

[walkingthedog]

OK, dump the clips they're a very bad weak spot. The DCC set talk about bus wires, droppers, soldered joints, supply the power directly from a National Grid pylon and make sure everything is spotlessly clean and electrically sound, then use things like staples that are held in place by nothing. Couldn't make it up really. 

[Zues]

OK, dump the clips they're a very bad weak spot. The DCC set talk about bus wires, droppers, soldered joints, supply the power directly from a National Grid pylon and make sure everything is spotlessly clean and electrically sound, then use things like staples that are held in place by nothing. Couldn't make it up really.

 

Absolutely spot on WTD, over time these clips will cause high resistance faults leading to melting point as we have seen elseware on the forum, the solution is simple get the soldering iron out or use another brand of points

[Fishmanoz]

Have to agree that point clips can be a source for high resistance leading to heating if there is serious current flow through them.  The current in John's case is thought to be from reversed polarity TT outputs wired the wrong way.  So it only happens for him when a reversed polarity output is in use.  Then how anything operates if such a condition exists, given 2 out of phase DCC signals are being fed to the track, I'm not sure.

 

So while point clips can be a problem, we also know they can work satisfactorily over extended periods because a number here report using complicated layouts without problems with single point connections.  John's reporting the clips are loose suggests faulty clips.  Can't say I've ever found my clips to be loose, they fit snugly and stay where put.

[walkingthedog]

You don't need serious current to get heat Fishy.   Fishplates can get warm with DC let alone DCC. I am conviced you were all looking for a complicated answer for Johns problem instead of looking for a simple answer. It hasn't been proved what cleared Johns fault. If you disconnect everything it's bound to clear. Nobody else has had problems with melting points due to a turntable.  We now have  two cases of points melting under the clips. Seems pretty clear cut to me. 

[Fishmanoz]

Just looking at how the clips are fitted, they are held in place by the plastic check rails, which keep the clip compressed and tensioned in place. Consequently, if any heating occurs, the first thing to get hot and melt will be the end of the check rail, meaning the clips will start to work loose as soon as this happens, leading to more heating and melting.  So loose clips may not mean they are faulty, rather they have already started to melt the check rails.  The point may be otherwise fine but you'll no longer be able to use clips with them.  

 

Also so if this is the mechanism, the heating will have only occurred at the clip on the track to which the point isn't set.  Does it seem to be the case that only one clip has been hot?