Electrical short - your help is requested!

[Andymsa]

39 minutes ago, newbryford said:

 

Ray has shown the insulators on both v-ends of the points - as suggested earlier.

The only thing I would do is move one of the two that form the crossover, so that they are opposite each other - for the district separation.

 

 

 

 

absolutely correct, I suggested the same yesterday  

[DY444]

2 hours ago, newbryford said:

 

Ray has shown the insulators on both v-ends of the points - as suggested earlier.

The only thing I would do is move one of the two that form the crossover, so that they are opposite each other - for the district separation.

 

 

 

 

 

I agree that would be better practice.  Not convinced it will solve this problem though.

 

My attempts to solicit information from the OP to diagnose this have largely fallen on deaf ears so I'm giving up.  Before I go however, and based on the limited information that has emerged thus far, my entry into the "guess what the problem is" sweepstake is this.  That the DCC bus for district 2 has been connected the opposite way round to the DCC bus for district 1 meaning locos will run fine in either district but there will be a short every time a loco bridges the insulated rail joiners between the two districts.    

 

[Dagworth]

2 hours ago, DY444 said:

That the DCC bus for district 2 has been connected the opposite way round to the DCC bus for district 1 meaning locos will run fine in either district but there will be a short every time a loco bridges the insulated rail joiners between the two districts.    

Which is what I suggested in the very first reply to this post. We don’t know whether the OP ever tried my suggestion 

 

Andi

[StanierBlack5]

I must apologise to Members who have offered advice and think that I have totally ignored it, that is not the case! Different approaches to solve my problem have been offered and I obviously have not offered more advice to help solve the problem so PLEASE have a look at the attachments as I need to get this problem sorted...!

 

'Loco_short' ... shows exactly where the short occurs ( after short piece of track).

'CP6'  ...  showing district 1 & 2 lit up with short.

'District bus wires'  ...  district #1 at the top and district #2 below showing feed to bus wires (district #2 showing left hand side bus wires only). 

 

Thanks in advance - as always.

Roger

 

  

[Gilbert]

Can you test your wiring using DC and a multi meter - that will quickly show if the feeds have somehow got crossed?

Chris

[Andymsa]

Things to look at and try.

 

A. Swap a district power feed on one district.

 

B. Frog power on right hand point in photo, is the power switching reversed.

 

C. Have you cut small wires on point where the gaps are, if your switching frog power.

 

from the photos I cannot see any wires to the frog. If your using the blades of the points why is there wires on the left hand point on the rails from the blades to the frog. And I would remove one set of adjacent irjs on the cross over section and remove the power wires to that section. In other words your creating an extension to the point.

[long island jack]

Think it would be helpful to us all, if you showed us how you've wired these points, all feeds, why have, what looks like feeds on that small piece of track?

[StanierBlack5]

To 'Gilbert' .. please see diagram.

 

To 'andymsa'  ...  All the points have been changed as per several modellers suggestion, small wires across gaps taken out etc., I switched around the power feeds to district #2 but it did not make any difference from what I could see.

 

To 'long island jack'  ...   Both these sets of points have yet to have power fed to them directly

my whole idea of the small piece of powered track was to power both sets of points in district #2.

As I suggested earlier, would it make a difference if I were to remove the small piece of track altogether and power the points directly?

[Ray H]

I modified several Peco points for improved DCC usage. All went in on the layout and I had a short when the layout was powered up. I checked and double checked and still no solution so I took each point out, one at a time, and found on the last one that I hadn't severed the electrical connection between the closure rails (the rails that link the blades with the frog) and the common crossing (frog).

 

It isn't clear from the picture which rails are linked to district 1 and which to district 2. This could be critical if one point in in the district 1 area and the other in the district 2 area as you've just posted that you want both points in district 2.

 

How far does a loco get when approach the crossover from the right (in the picture) on the bottom track?

 

The image with the loco isn't clear unless there are pick-ups on the bogie/pony wheels as well as the driving wheels.

 

If the loco is moving from left to right I can't see how it has moved so far along the short section of track. Surely it should have stopped when the moment the first driving wheel crossed the rail join not a few centimetres after. That said, the short does appear to be being caused by a reversed polarity connection on the track at the extreme bottom of the picture.

 

If the leading bogie wheel picks up track voltage the frog of the point it is travelling towards would appear to be wrongly wired. That may account for you not getting a voltage reading on the two lower points. That said, you don't seem to show any track power connections to those two points.

[long island jack]

First are frogs 1 and 2 on photo powered via a switch/point motor etc, i see you've bonded the rails on both points?.

if so, do away with the track feeds on that small piece of track, add metal fishplate as shown, add temporary feeds where shown and test

[StanierBlack5]

Firstly, 'Frog 1' (in District #1) and 'Frog 2' ( in District #2) are both powered by 'iP Digital' point motors.

 

Secondly, I will disconnect both power feeds to the short piece of track plus add feeds to the both set of points which are both residing in District #2 and report back tomorrow.

 

Cheers, Roger

[Andymsa]

1 hour ago, StanierBlack5 said:

Firstly, 'Frog 1' (in District #1) and 'Frog 2' ( in District #2) are both powered by 'iP Digital' point motors.

 

Secondly, I will disconnect both power feeds to the short piece of track plus add feeds to the both set of points which are both residing in District #2 and report back tomorrow.

 

Cheers, Roger

don’t forget to change the rail joiners as Long Island jacks photo shows on the short piece of track.

[Grovenor]

2 hours ago, StanierBlack5 said:

Firstly, 'Frog 1' (in District #1) and 'Frog 2' ( in District #2) are both powered by 'iP Digital' point motors.

Cheers, Roger

THen one or other of these frogs may be switching the wrong way, probably the one on the right if you can run through the left turnout  straight on district 1.

But you certainly should NOT feed to that short piece of track, feeds should always be to the  toe (switch end) of turnouts.

[StanierBlack5]

Today I disconnected the power feeds to the short piece of track and added a power feed to each of the two points mentioned - see diagram. 

 

Switched the power on both districts and run a loco over the points in both directions with the following result - loco running from left to right caused a short on district #1, the reversing along district #2 from right to left caused a short on district #2. Please see diagrams.

This is after taking up the track and points in question including the point motors which rally tried my patience re-installing them, and just when I thought well that's that job done, I now have two shorts to fix, so now it's off down stairs where a glass of red awaits!

 

Cheers, Roger

[Andymsa]

This is certainly indicating either the district power on one district needs the wires to be swapped or the frog switching needs to be checked that it is in sync with the position of the blades. You don’t have two shorts it’s just the same short.

[KingEdwardII]

Roger,

 

Looking at your most recent pictures above, and the fact that you get separate shorts for District 1 and District 2, I think that the problem is most likely caused by the frog of each point having the opposite polarity to the curved switchblade. I say this since it is suspicious that the loco driving wheels appear to straddle the gap that exists between the curved switchblade and the rail leading up to the frog, in both cases.

 

It should be straightforward to test this hypothesis with a multimeter - check if there is a voltage between those two positions on the track - it should be zero. If there is a voltage here, then the power feed to the frog is wrong and needs switching over.  

 

Mike.

 

PS. Which red is in your glass??

[StanierBlack5]

Hi Mike,

 

Just checking the PC before shutting down ... although born and bred in Yorkshire, I spent 42 years in Australia and therefor my poison of choice is - 'Hardy's Crest, Cabernet, Shiraz, Merlot', a lovely drop of the red stuff! 

 

I'll no doubt be having a look at my latest model rail problem tomorrow!

 

Cheers, Roger

[StanierBlack5]

Hi Andymsa & KingEdward11,

 

Thanks for your input - I'll let you know how I go!

 

Many thanks, Roger

[DCB]

There doesn't seem to be any logic to the fault finding.  Its as if the earliest most relevant posts have been overlooked in favour of later suggestions which were based on the idea the earlier suggestions had been tried without success.

Assuming the suggestions in posts 2/3 etc have been tried and discounted I wonder does this  fault occurs with other locos.   

 The tracklaying looks really tatty with missing sleepers so is possible the leading wheels are hitting the metal running plate assuming the Radial has a metal running plate.   Our Hornby T9 always shorts over a certain point.  Has an 0-4-0 or 0-6-0 been tried?. 

This is one fault my 2 wheel pick up test loco would possibly not have detected but if a 2 wheel pick up loco won't roam everywhere on the layout I find out why and put the fault right.

Testing the electrics with (12 volt 1 amp) DC would show up reversed connections, as soon as a train crossed from one section to another without subjecting fishplates and point blade tags to more amps than they can handle.  Long experience has proved that once they fail due to overload fishplates need to be binned, you can't clean the inside surfaces, they have to be replaced

[StanierBlack5]

Hi Everyone,

 

Mike, please see the attachment and I hope it's of some help towards solving my problem!

 

Cheers, Roger

[StanierBlack5]

DavidCBroad,

 

Thanks for your input, I've now learned another lesson with regards to member's suggestions, initially I had a few answers and instead of acting on each one until the problem was solved, the more I read, the more confused I got.

 

Back to the present, I've implemented what was suggested early on in the piece temporary linking district #1 'live' to district #2 'live' which caused a short in district #2, so does changing the bus feeds on district #2 literally mean changing the bus wire feeds over ('red' to 'black' and 'black' to 'red')?

 

Thanks for your input.

 

Cheers, Roger

 

 

   

[Grovenor]

As has been said several times, check that the frog polarity switching is working correctly. The left hand turnout clearly has the frog polarity wrong so the DCC feed to the cobalt needs to be reversed.

[Pete the Elaner]

Hi,

 

There are some things which look wrong with your diagram & others which are impossible.

Assuming you have used 0v & 18v to represent the polarities (phases) then the centre 4 feeds should not all be 18v. 1 rail should be 18v & the other 0v.

I have marked things in green on the right hand point. All the places circled in green should have the same value. I have also underlined 3 of these. They are on the same piece of rail so they must have the same value.

Since your problem is with the left hand point. The 2 places circled in purple are on the same rail so they must have the same value.

Have you cut the links beneath the rails? If not, then the 0v circled in blue must be wrong. If you have cut the links, then this is ok if you are taking your measurements at the switched side of the insulated section, although this would mean the 2 values circled in red should always be different. If you did not cut the links then the 2 values circled in red should be the same.

It would help if you could keep one of the multimeter probes in the same place & state where this is. It is not clear from your diagram.

 

 

 

Edited November 11, 2020 by Pete the Elaner
Updated image & stressed a couple of things

[KingEdwardII]

Roger,

 

If your picture shows the multimeter measurement places correctly, then I think that the left hand point shows that the frog has the wrong polarity when the turnout is set to the diverging (i.e. curved) route.

In this case, the extreme left measurement should be 0V, i.e. the frog should be the same polarity as the bottom stock rail - but it is showing up as 18V. So as your loco passes over this turnout, once the driving wheels straddle the gap between the lower switch rail and the frog, 18V passes across the driving wheels on that side since they are electrically directly connected.  Result: a short.

 

You need to examine the mechanism for providing the feed to the frog - it isn't working correctly. I think you said that you're using Cobalt iP Digital point motors - you should cross-check your wiring with the iP Digital manual - it looks like terminal 3 is the feed for the frog, while terminals 1 & 2 are the DCC input. It may be that you need to swap the connections to terminals 1 & 2 to get the correct polarity. I'm not a Cobalt user, although the MTB MP1s that I use do have a similar kind of arrangement and it is possible to get the polarity the wrong way around. 

 

I find that my multimeter is my best mate when wiring up the layout - and I check all the polarities and voltages before I let a loco loose on the track.

 

Good luck,

 

Mike.

[StanierBlack5]

Hi Everyone,

 

It may help (me) if you show me where exactly I need to place my multi meter probes on the point frogs to get the voltage that you are looking for and meanwhile, I will reverse the DCC inputs on the left hand point (tomorrow morning) to see if that has any effect.

 

Thanks as always, Roger