Separate bus for turnout motors?

[AndrueC]

Hi, my big project for Winter (yeah I know but I like to plan in advance) is to install turnout motors and LED signals on my layout. I'm currently using an NCE PowerCab and run a maximum of two N-gauge locomotives at a time with six others sat powered but idle. Should I add a second power bus just for the turnouts? Should I buy a booster so that though controlled from the same 'Cab they have their own power?

 

There will be over a dozen turnout motors but they will tend to be switched infrequently, mostly just to select a different train to run rather than as part of a route or for shunting.

 

I'm going to be using DCC Concepts Cobalt-SS motors and associated kit.

Edited July 24, 2021 by AndrueC

[JST]

I guess you don't really need an accessory bus for the points or a booster due to the power requirements of your layout. However, the benefit of a separately powered accessory bus is that if you trip the power on the track for some reason (derailment etc.) you can still change the points. I have a separately powered accessory bus but then, I have over 60 sets of points all powered by DCC Concepts ADSX decoders so I need the extra 4 amps of the bus on start up!

[WIMorrison]

If you want to use a separate accessory bus, which I would highly recommend, then you would place the booster or power district cutout on the track circuit not the accessory circuit (though you could put on eon both).

 

The reason you want a separate bus is to enable you to change turnouts when the track shorts due to overrunning a turnout, this is cutout on the track as that will mean whilst the track is isolated (and will automatically reset) the accessory bus still works, so you can change the turnouts.

[Edward]

Adding my farthing's worth, is it worth the extra wires and connections just to help in the rare short?  The hand of God would still be needed to push the loco off the point.

[Nigelcliffe]

On 24/07/2021 at 10:46, AndrueC said:

I'm going to be using DCC Concepts Cobalt-SS motors and associated kit.

 

If you dig around this and other forums, you'll find very mixed views on those motors.  Suggest you get the smallest pack to try them before spending lots on a large pack.     

 

My experience of them was dire, and a large box was returned unopened to retailer in return for a credit note.  The one opened still sits around looking for an application where it is reliable.    They seem very sensitive to how they're installed; small changes in screw tensions, alignment, etc..    I'm usually pretty good on high precision stuff, scratchbuilding locos in 2mm and 4mm scales, designing tiny gizmos, etc.. 

 

 

 

- Nigel

Edited July 26, 2021 by Nigelcliffe

[WIMorrison]

Totally agree with Nigel, I tried a couple because I had an area where I couldn't fit my usual motors and I ended up moving some items to allow me to use my normal MTB MP1 motors as the Cobalt-SS motors were hopeless.

[ISW]

1 hour ago, Edward said:

Adding my farthing's worth, is it worth the extra wires and connections just to help in the rare short?  The hand of God would still be needed to push the loco off the point.

My arrangement is separate power bus for turnouts (servos operated by MegaPoints controllers) and tracks with several power districts, each with a MERG short circuit device (SCD). The controller is an NCE PowerCab.

 

I get a short when I trail an electrofrog turnout with the switch incorrectly set (human error each time), and the MERG SCD buzzer for that district sounds, and power to that district is cut. I press the button on the turnout mimic panel to operate the switch, the SCD clears the short automatically, and control is resumed by the PowerCab without me having to do anything. The loco just moves off with the same DCC settings (although the end lights do need resetting).

 

So, using separate power supplies (and the MRG SCD) means that the 'hand of God' can be avoided.

 

Ian

[WIMorrison]

2 hours ago, Edward said:

Adding my farthing's worth, is it worth the extra wires and connections just to help in the rare short?  The hand of God would still be needed to push the loco off the point.

 

yes - it is worth the additional effort and no, the hand of God is not required

[Andymsa]

A quite decisive subject indeed, personally I would have a separate bus if I was you, having 260 points I certainly need it. As to colbalts least said the better, all my points are thrown by tortoises and not one has failed to date. 

[KingEdwardII]

18 hours ago, Edward said:

is it worth the extra wires and connections

The only extra wires are a pair running around the layout sufficient to reach all places that have turnouts & motors. Pretty straightforward.

 

There are no extra connections - you have the same number of connections, they simply go to the accessory bus rather than the track bus.

 

Yours, Mike.

[Edward]

On 27/07/2021 at 11:58, KingEdwardII said:

The only extra wires are a pair running around the layout sufficient to reach all places that have turnouts & motors. Pretty straightforward.

 

There are no extra connections - you have the same number of connections, they simply go to the accessory bus rather than the track bus.

 

Yours, Mike.

Hi Mike,

One does begin to worry that you've done it all wrong after all!  I suppose I've been too influenced by exhibition experience where the banks of choc blocks and linking cables nearly always gives you a headache or two.

Funnily enough, I've just had an unusual reaction when running a macro which has 10 cobalts having to move. The relevant light on the CP6 circuit breaker came on till most of the motors had moved.  So got onto Richard at DCC Concepts who, after checking with tech staff, confirmed that it was perfectly OK and no damage to locos or point motors would occur.  Adding up the current draw it is well under the 1 amp limit.  However a club member explained that when you get near the limit (of current) "funny things happen" in electronics!  I was happy to leave it at that.   

My pursuit of the one cable principle has led me into expensive and complicated solutions.    My worst has been to use a programmable relay and DCC to DC converter to switch a bank of LEDs !

Cheers

 

Edward

[Michael Hodgson]

On 26/07/2021 at 17:32, Edward said:

Adding my farthing's worth, is it worth the extra wires and connections just to help in the rare short?  The hand of God would still be needed to push the loco off the point.

It can certainly be argued that if you run your layout properly you won't run locos into points that are set incorrectly, they will stop at signals which will be against the movement, so such shorts will not occur. 

 

On a large and complex layout without power districts a short can be difficult to locate, but even if you have a separate power bus you still have to locate the problem in order to correct the setting of the offending point.  Such zoning is OTT on a smaller layout though.

 

All the same, I choose to run a separate bus as it still simplifies fault finding if the cause turns out to be the very rare event of a short on the accessories rather than the track.