Silly power question

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james2k
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Silly power question

Postby james2k » Mon Aug 01, 2011 9:51 am

Hi,

I have a rather silly power question....

I am going to have a largish amount of LED lights on my layout and point motors...

Am I best using 2 adapters? or will 1 suffice?

Also my layout has grown from 12x4 ft layout to 12x4 with 6x4 seperate oval linked up to the main board. I don't think there is enough power to run this layout from 1 4amp hornby adapter (got the elite) or am I being ridiculous?

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Bufferstop
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Re: Silly power question

Postby Bufferstop » Mon Aug 01, 2011 11:25 am

Depends how many trains you run at once, and what other continuous current drain (lights etc) you have? Do you intend to control the points from your DCC controller or from lever switches?
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Roger (RJ)
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Re: Silly power question

Postby Roger (RJ) » Mon Aug 01, 2011 12:09 pm

It's best to have two separate power supplies.
The one for points is usually advised to be 16V AC. If you are using a CDU then refer to the instructions for guidance on the maximum voltage to use.
The power supply for the LEDs should ideally be a regulated DC type. The number of LEDs and how you wire them (in series or in parallel) will determine the voltage and current capacity of the power supply you need.

The Elite with a 4 amp power supply (3 amps to the track and one amp for the aux output) should be able to run upto about 10 modern locos. The size of the track is almost irrelevant as long as enough power feeds are used. Sound fitted models take a bit more power. Older model may take upto about 1 amp each.

You could use the Elite's Aux output to power your LED's. I did until I found a spare power adaptor.

james2k
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Re: Silly power question

Postby james2k » Mon Aug 01, 2011 2:11 pm

200 leds? (no its not the london eye)

Each of the points has a capacitor in line with SPDT switches.

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Roger (RJ)
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Re: Silly power question

Postby Roger (RJ) » Mon Aug 01, 2011 2:56 pm

Go to LED wizard and put in the required information and it will calculate the requirements your LEDs
"Source voltage" (from the Elite) is 15
"Diode forward voltage" is about 4.5 volts for white LEDs and about 2.5 volts for standard red and green
"Diode forward current" is anything between about 10 and 20 mA depending on how bright you want them. Don't run them at the rated maximum (which is normally about 30 mA) as they won't last very long and will probably be too bright.
Then enter the number of LEDs and click on "Design my array". It will come up with 2 or three options.

I think 200 LEDs fed from the Elite is pushing it a bit. :)

james2k
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Re: Silly power question

Postby james2k » Tue Aug 09, 2011 9:48 am

Ok. going to use one of the small hornby controllers (silver coloured one) to power the lights.

What about my points? each have a SPDT switch and there own capacitor as per one of my other threads.

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pete12345
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Re: Silly power question

Postby pete12345 » Tue Aug 09, 2011 10:19 am

I power my points in the same way, and I found that using a 16v AC transformer giving 2 Amps, a full wave rectifier and a CDU give reliable operation. The CDU charges to around 24v.
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james2k
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Re: Silly power question

Postby james2k » Tue Aug 09, 2011 12:35 pm

Can I just use a spare hornby power adapter for this?

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pete12345
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Re: Silly power question

Postby pete12345 » Tue Aug 09, 2011 8:46 pm

Any 16v power supply should work fine. The hornby unit is a bit low-powered so may take a couple of seconds to recharge the CDU, but will probably give perfectly satisfactory operation. With an AC supply, the peak voltage is higher than the stated voltage which is an average, hence why the CDU will charge to about 24v.
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james2k
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Re: Silly power question

Postby james2k » Tue Sep 13, 2011 6:36 pm

Would a 24v transformer be to much to power 30+ points?

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Flashbang
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Re: Silly power question

Postby Flashbang » Tue Sep 13, 2011 6:55 pm

james2k wrote:Would a 24v transformer be to much to power 30+ points?

No,
Many CDUs can work happily with 24 volts ac. However you should check the documentation or web site to ensure the CDU will work with 24volt input.
Often this can also often be gained by looking at the CDU capacitors, they should have a dc working voltage written on them (plus their µF value), this voltage needs to be 35 volts or higher for a 24 volt input.
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jcm@gwr
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Re: Silly power question

Postby jcm@gwr » Fri Sep 16, 2011 8:57 am

Hi james2k,
If you really are using 200 led's, I doubt that you want them all on at the same time or that
you look forward to wiring them all to individual switches!
I suggest you look up 'Micro-Miniatures' as they do infa-red remote controls for lighting,
multi channel plus dimming and memory.
Cheers, Jeff

james2k
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Re: Silly power question

Postby james2k » Fri Sep 16, 2011 6:34 pm

I was thinking of having a switch board? But am concerned about powering it? as over voltage would blow the lights?

james2k
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Re: Silly power question

Postby james2k » Sun Sep 18, 2011 4:06 pm

Hi all,

Hopefully last question about powering these points.
Will the adapter in the ebay link below be ok? or does it need to have more amps?
http://www.ebay.co.uk/itm/24V-Volt-Main ... 5d302f7b19

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Flashbang
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Re: Silly power question

Postby Flashbang » Sun Sep 18, 2011 5:30 pm

Hi
It will charge a 24 volt CDU ok, but would take a couple of seconds after each operation before the next point move.
As its only 0.1 to 0.4 Amp output.

We are talking of one CDU for all points.

You would not be able to run LEDs as well form this as there isn't enough power available.
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