Hornby Select, external power and OL

[WhyD]

Hopefully a basic misunderstanding, as I have little experience.
 

I've placed am oval track, connected the select to it and I can run my DCC locomotive just fine
 

However, I need to power my track more strongly than the select would allow, so I connected external power to the track. 
 

Without the select the loco runs fine, obviously with no ability to control it.
 

If I connect the select in parallel (thorough a separate track section to the external power) it shows overload. 
 

Is that not how it's supposed to work?

 

Thanks in advance....

[Pete the Elaner]

A booster is like a hifi amplifier. It accepts a low level DCC signal as an input & outputs a high power signal to the track.

Would you connect the Line Out of a CD player directly to a pair of passive speakers then connect an amplifier to the same connections? A DCC booster works in a similar way to an amplifier.

It really sounds like your needs are too demanding for a Select. It is a basic system not designed for expansion (other than being used as an additional handset for an Elite). It should cope with a couple of OO locos though.

[Dungrange]

1 hour ago, WhyD said:

Is that not how it's supposed to work?

 

No

 

1 hour ago, WhyD said:

However, I need to power my track more strongly than the select would allow, so I connected external power to the track. 
 

Without the select the loco runs fine, obviously with no ability to control it.

 

What is this 'external power to the track'?

 

Power to the track should only be coming from the Select (or a separate Booster if the system is capable of expansion, which I don't think the Select is).

 

My understanding is that the Select comes with a 1 Amp power supply, but that this can be replaced with a 4 Amp supply if more power is required, but I think this would just replace the 1 Amp supply that you are using at the moment.  That is, you plug the higher current transformer into the Select and then connect the Select to the track as before.

[RAF96]

Connecting a separate power supply to the track is likely to damage the controller, depending upon what that supply output is.

 

Use the 4-amp power brick from the Elite if you need to run more locos from your Select.

 

Folk often think a DCC Booster is adding more oomph to the existing track but it doesn’t. A DCC Booster is connected to an isolated power district powered by the booster module power supply. The DCC signal is passed from the one and only DCC controller to the Booster module which passes it to the second power district.

 

If your controller has Boost terminals (which the Select doesn’t have) these output low energy DCC signal to the Booster module. Connecting these Boost terminals to the existing track will also kill your controller.

 

[GoingUnderground]

On 20/02/2021 at 22:50, WhyD said:

Hopefully a basic misunderstanding, as I have little experience.
 

I've placed am oval track, connected the select to it and I can run my DCC locomotive just fine
 

However, I need to power my track more strongly than the select would allow, so I connected external power to the track. 
 

Without the select the loco runs fine, obviously with no ability to control it.
 

If I connect the select in parallel (thorough a separate track section to the external power) it shows overload. 
 

Is that not how it's supposed to work?

 

Thanks in advance....

You are very, very, lucky that the Select only registered an overload.

 

NEVER connect a DC or low voltage AC power source to a layout when the layout is also connected to a DCC controller. If you break that rule it can destroy the output transistors on the DCC system. That's why I say you are very fortunate that all the Select did was register an overload, when it could have turned up its toes.

 

As others have said, you can replace the 1 amp power supply unit that comes with the Select with one with a higher amperage. There appear to be 2 suitable PSUs made by Hornby the C7024 or the P9300, sorry I don't know which is the currently available one. But it takes the place of the PSU supplied with the Select and is NOT an additional power supply for the layout.

 

If the higher output PSU still isn't enough, then you have to split your layout into two electrically separate sections, power one with the Select and the other with a DCC booster. A DC or low voltage AC power supply on its own is not a DCC booster.

 

But I don't think that you need to go that far yet. You've talked about your DCC loco on your oval of track, which implies that you only have 1 DCC loco and a single track layout. But you say that you need to power it "more strongly". Why? The Select should be more than adequate for a single loco on a single track layout, at least on OO gauge.

 

You need to tell us more about your layout, e.g. scale/gauge, number of DCC locos, number of non-DCC locos, whether your carriages have interior lights, how you're powering and operating any solenoid point motors, etc. before the members on here can give you advice more suited to your problem of needing more power.

 

 

Edited February 22, 2021 by GoingUnderground
To remove a potential ambiguity.

[WhyD]

Thank you all, clearly a mistake and a likely escape (select still works!)

 

To provide answers to some of the questions, for completion -

• The track is expected to be larger than the simple oval I put just for testing, hence needing more power.
• The power supply I use is a regulated 15V power supply providing 10A of current. 
• I know the select has a 4A power supply (which I don't have), so I was hoping to use this one. I think I have another which is around 2.5A so it would be a good fit and the larger one can be used for frogs I suppose. 
• The scale is OO using Hornby tracks and I've just started thinking about it (and built the table for it) so currently only 1 loco, but I expect to add more as I progress

 

Pete - I loved the amplifier analogy, it really worked for me. 

 

Thanks again all for helping the newbie!

 

[Nigelcliffe]

17 minutes ago, WhyD said:

Thank you all, clearly a mistake and a likely escape (select still works!)

 

To provide answers to some of the questions, for completion -

• The track is expected to be larger than the simple oval I put just for testing, hence needing more power.
• The power supply I use is a regulated 15V power supply providing 10A of current. 
• I know the select has a 4A power supply (which I don't have), so I was hoping to use this one. I think I have another which is around 2.5A so it would be a good fit and the larger one can be used for frogs I suppose. 
• The scale is OO using Hornby tracks and I've just started thinking about it (and built the table for it) so currently only 1 loco, but I expect to add more as I progress

 

Pete - I loved the amplifier analogy, it really worked for me. 

 

Thanks again all for helping the newbie!

 

 

How big do you expect this table layout to be, when finished ?   How many trains moving simultaneously ? 

 

10A is silly for OO, unless you want to melt track and set fire to locos.  

Even 4A is over the top for most layouts.  

As you increase the current out from boosters, the quality of the layout wiring has to improve - both the cross-section of wire used, and the quality of all wiring joints.  Otherwise the short-circuit detection won't function.  

 

Large layouts often benefit from dividing into power-districts.  With those, a moderate sized system powers the entire layout (say 4A), but each "district" is protected by its own cut-outs.   The cut-out might be set at 2A.   This means that only the district stops if there is a fault/short circuit, the remainder stays running.   But, also, the maximum current to any single location is then the cut-out limit (2A).     Large layouts are not usually run from a Select.  

 

 

 

 

 

 

[RAF96]

Adding to what Nigel has said.

The 1-amp power supply protects in a fault condition by dropping its output voltage. This causes the Select to continually reboot - the screen will keep showing the startup sequence of numbers over and over while the fault is present.

The 4-amp power supply relies upon the Select taking care of overloads and shorts, by way of what is commonly termed an internal self resetting fuse (Select).

If using your 2.5-amp power then what protection does it have as you will not reach the Select self protect level.

Even if you can connect your 10-amp unit the Select will self protect at its internal limit, hopefully before the mega-psu can burn its way through the fault.

[GoingUnderground]

7 hours ago, WhyD said:

Thank you all, clearly a mistake and a likely escape (select still works!)

 

To provide answers to some of the questions, for completion -

• The track is expected to be larger than the simple oval I put just for testing, hence needing more power.
• The power supply I use is a regulated 15V power supply providing 10A of current. 
• I know the select has a 4A power supply (which I don't have), so I was hoping to use this one. I think I have another which is around 2.5A so it would be a good fit and the larger one can be used for frogs I suppose. 
• The scale is OO using Hornby tracks and I've just started thinking about it (and built the table for it) so currently only 1 loco, but I expect to add more as I progress

 

Pete - I loved the amplifier analogy, it really worked for me. 

 

Thanks again all for helping the newbie!

 

Nigel is right that 10 amps is excessive. It also has another downside in that it might damage the Select as Hornby may not have designed the Select to be able to cope with a 10 amp supply. But I'd hope that its short circuit/over current protection would cut the track power before any damage occurred.

 

If you have a 2.5 amp one, use that and see how you get on. If that isn't enough, you could get the 4 amp Hornby PSU, they don't seem to be too expensive. But you only need the higher amperage if you have several locos on the move at the same time, and the Select isn't the ideal controller for that. If you need more than 4 amps, then you're into sectioning the layout and using DCC boosters.

 

Also you said that you might use the larger (10 amp PSU) "for frogs".  If you mean using it to power the frogs on points, you can't do that as I believe that most if not all "frog juicers" need to be connected to the DCC supply.

 

You might be able to use it to power your solenoid point motors if you are intending to use conventional passing contact switches like the black Hornby one R.044 (RT.44 when I started modelling). If you do want to be able to operate your electric points from the Select then you'll need accessory decoders, and only soem of those allow the use of an external PSU. 

Edited February 23, 2021 by GoingUnderground