Jump to content

neilneil

DC wiring - Help please!

Recommended Posts

Hi I'm hoping someone can help with a wiring problem. I have wired up about 10 ft of layout using double throw switches so that most of the track can be powered by one of two controllers. When I tested it the loco ran very slowly. When I put another loco on a different section with the switch centre off they both ran! I don't understand how, as all the centre contacts lead to the track?

Could it be because the returns are all joined together and then split to connect to both controllers? Is it a short somewhere?  Or would that mean no movement at all? Or have somehow linked the feeds from both controllers? Any help or advice very much appreciated.  Thanks,  Neil 

Share this post


Link to post
Share on other sites

It does sound as if you may have wired the switches wrong. Do you have a diagram of how you wired them, and/or a close up photo of the switches, showing which wire goes where?

Share this post


Link to post
Share on other sites

you have insulated rail joiners (fishplates) between each section of track (zones)

trevora

Share this post


Link to post
Share on other sites

From your description (and a diagram would be useful) I would expect the 'centre' terminal of the DPDT switches to be connected to the section of track (separated by insulted joiners) and the two sets of outer terminals to be connected with each set going to a controller.   I wouldn't expect returns to be joined together. This arrangement will only work with two controllers but will ensure only one controller can be linked to any section of track at one time.

Share this post


Link to post
Share on other sites

There seems to be a little guesswork needed here.

Electrical problems can be frustrating & can take time. Understanding them can be rewarding so please have patience.

 

Do you have a multimeter? From your description, it sounds not. If not, one would be very useful. Many people consider these solely as voltmeters, but I rarely use any of mine for measuring voltages. I find resistance much more useful.

 

If you need to buy one, I would recommend one which makes a sound when you have a good connection.

You may be able to find one in a supermarket, but there will also be places selling them online.

Turn layout power off, set the meter to resistance/beep then test where you think there should & should not be a connection.

Hopefully you will find something you don't expect.

Share this post


Link to post
Share on other sites

If I understand you correctly what you appear to have is a version of 'cab control'  where you split both feeds.  It may be worth doing a search on cab control and using it as a guide for fault finding.  Echo buying a multimeter if you dont have one although it is not clear where you might be able to get one right now.

Share this post


Link to post
Share on other sites

It is indeed Cab control but since the OP describes a common return only the other feed should be switched with insulated joints in the non-common rail.

It is essential to this common return wiring that the two controllers have completely independent supplies, if not you can get symptoms as described.

So first essential is to know what the controllers are and how they are supplied with power, second essential is a diagram of how the wires are connected.

Without these, as can be seen above, we all make different assumptions about what the OP meant.

  • Like 1

Share this post


Link to post
Share on other sites

Disconnect one controller completely, both wires not one, and see if the problem persists, check every part of the layout with every combination of locos and sections switched on and switched off.

if the problem has gone away with only one controller connected it suggests common return could be the cause. But now reconnect the controller and  disconnect the other, both wires, and see if that also cures it.   If not there could be a wiring or switch fault.  Blob of solder bridging two centre off  switch terminals is a common issue, or indeed connecting to the wrong terminals.

If it still messes about please supply a diagram of the wiring and track layout with insulated rail joiners marked and we will offer several conflicting suggestions on what has gone wrong.

  • Agree 1

Share this post


Link to post
Share on other sites

Thank you so much everyone for your replies. I really appreciate the time and effort you have taken to help me out. it turned out that that rails were touching where they should be isolated so I've put milliput in to ensure the gaps stay apart. I had checked the rails previously and they were ok but must have come together when moved. This has really helped me to progress at a time when I was pulling my hair out. Now I'm encouraged to get on with the rest of it. Thanks again 

Share this post


Link to post
Share on other sites

 

 

1 hour ago, neilneil said:

........rails were touching where they should be isolated so I've put milliput in to ensure the gaps stay apart. 


 

If you haven’t used insulated rail joiners watch out for the warmer weather. Rail expansion could lead to similar problems.

  • Like 1

Share this post


Link to post
Share on other sites
On 01/04/2020 at 20:20, Theakerr said:

If I understand you correctly what you appear to have is a version of 'cab control'  where you split both feeds.  It may be worth doing a search on cab control and using it as a guide for fault finding.  Echo buying a multimeter if you dont have one although it is not clear where you might be able to get one right now.

I have not tried them since the Covid lockdown, but my usual supplier of choice for electronic components would be rapidonline.com.

Since their business is based largely around mail order, I would expect this part of the business to be running virtually as normal.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.