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PC Lap top power supply for digital train?
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wurttemberg Offline
#1 Posted : 09 May 2012 08:22:10(UTC)
wurttemberg


Joined: 10/03/2006(UTC)
Posts: 74
Location: ,
Hi,
Just a thought: Most PC lap tops comes with a power supply providing 19.5 V DC and mostly > 65W (3 - 5 Amp, depending on the power supply).
This seems to be well suited (and much cheaper) for CS or other Märklin digital control devices. I plan to investigate this myself (Is the voltage accurate/nominal and stable enough?, How effective is short circuit protection? etc.)

Has anyone already tried this out? Any experience or thoughts about this?

//Wurttemberg
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H0 Offline
#2 Posted : 09 May 2012 08:55:12(UTC)
H0

Germany   
Joined: 16/02/2004(UTC)
Posts: 6,809
Location: Cologne, NRW
Hi,
IMHO it's OK to use laptop power supplies or universal switching-mode power supplies if they have double insulation and are not earthed (input and output have two-pin plugs).
Some have three-pin plugs on both sides and I'm afraid they are earthed; I wouldn't use those.

The short circuit protection should be in the CS or booster.

Universal power supplies / laptop power supplies often come with adjustable output voltages and a variety of plugs - normally including the correct plug for an MS or a CS1.

For my CS1 reloaded I use the ESU power supply that came with it, for my MS2 I use the Märklin power supply that came with it.
Earlier I made tests with CS1 and MS1 using a laptop power supply and a universal power supply - without problems.

Warning: It worked for me, but I don't give you any guarantees!

Warning: Do not use desktop power supplies (they are earthed an not suitable).
Regards
Tom
---
Suaviter in modo, fortiter in re
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Goofy Offline
#3 Posted : 09 May 2012 18:05:15(UTC)
Goofy


Joined: 12/08/2006(UTC)
Posts: 4,703
Location: Helsingborg, Sweden
If there is zero ground connecting to earth ground i suggest you shall not use PC laptop connecting like that!!!
The power feeder to digital system is only allowed with 2 wires name red and brown which equals to see as phase and zero.(If with DC like + and -.)
It has to do with trafo and reciever.
Depends what in use.
In industry we use zero ground and earth ground togehter for trafo.
While reciever we use - connecting with earth ground too.
In this way...you can never do that in digital system!
Sincerely
Anders

DCC
Era 1a and b
Preussen,Bayern and Wurttemberg

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perz Offline
#4 Posted : 09 May 2012 21:02:53(UTC)
perz

Sweden   
Joined: 12/01/2002(UTC)
Posts: 2,423
Location: Sweden
Many laptop power supplies have the minus pole of the output connected to mains ground. This can create funny and less funny effects if you have grounded power outlets. So be careful!

Personally I experienced a "funny" effect because of this. All my turnout lamps were on although there was no supply to them (except through the mains ground, which I found out after troubleshooting). I'm happy nothing worse happened.
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Bigdaddynz Offline
#5 Posted : 09 May 2012 21:19:46(UTC)
Bigdaddynz

New Zealand   
Joined: 17/09/2006(UTC)
Posts: 12,201
Location: New Zealand
Is it OK to use a laptop power supply with 3 pins that has the earth pin disconnected?


I did that once with my audio power amplifier, which had some ground loop issues which caused an audible buzz through my speakers. Removing the earth pin fixed the ground loop issue, and I never had any other problems with the amplifier, but if there ever was a short between the live feed and the metal chassis, things might have got interesting!
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H0 Offline
#6 Posted : 09 May 2012 21:38:34(UTC)
H0

Germany   
Joined: 16/02/2004(UTC)
Posts: 6,809
Location: Cologne, NRW
Originally Posted by: perz Go to Quoted Post
Many laptop power supplies have the minus pole of the output connected to mains ground.
If it has a class II symbol then it must not have ground connection.
For MRR I'd use only power supplies with class II symbol (two nested squares).

See also:
http://en.wikipedia.org/...pliance_classes#Class_II
Regards
Tom
---
Suaviter in modo, fortiter in re
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JohnjeanB Offline
#7 Posted : 10 May 2012 12:10:38(UTC)
JohnjeanB

France   
Joined: 04/02/2011(UTC)
Posts: 68
Location: Paris, France
Hello
I did use a laptop switching power supply from a Compacq (65VA) .
It works OK with the following remarks:

- Output (secondary) is usually a triple shielded cable (Plus, Minus, digital information exchange between the PS and the computer)
- Identify and connect only the + and minus of the regulated output '19 volts DC in my case) and disregard (do not connect)
the digital information wire (the central pin usually).
- There is no connection between the mains ground and the secondary voltages so it is safe to connect a CS (CS1 and CS2 in my case, I tried with both of them).
- The drawback using a laptop PS is that, the PS turns off very abrutly when over current is detected, causing the CS1 or CS2 to reboot with all loks stopped . I get aggravated to be forced to reprogram the speed on all my locs.

Because of my increasing power needs, I am now using a 100 W märklin switching power supply (60101 if I am correct) for my CS2 -60214 TOGETHER with a 2 mm² ring feeder.

Full 5 Amps are now available, a very graceful over-current detection that causes no destructions to the shorting unit (wheel, current feeder, relay contact, etc). All this is probably coming from the latest CS2 s/w (2.0.1 in my case).
King regards from Paris
Jean

My floor installation can be seen here: http://www.youtube.com/w...ture=channel&list=UL
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wurttemberg Offline
#8 Posted : 16 May 2012 20:42:06(UTC)
wurttemberg


Joined: 10/03/2006(UTC)
Posts: 74
Location: ,
Thank you,
All of you for sharing your experiences. I assumed someone must have tried this out earlier.
Best regards,
Wurttemberg
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DaleSchultz Offline
#9 Posted : 29 October 2012 01:07:33(UTC)
DaleSchultz

United States   
Joined: 10/02/2006(UTC)
Posts: 2,032
I have used a PC power supply to provide DC power to my layout and it shares a common ground with the digital system.
http://layout.mixmox.com/1/5_Volt_power

I visualize the power system on my layout as seen here: Note the green line for DC is now at +12V instead of 5V

Can someone explain what the problem is with using a grounded power supply?
Dale
Arrival and Departure signs: http://remotesign.mixmox.com
My layout: http://layout.mixmox.com
IB Software: http://bw.mixmox.com
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H0 Offline
#10 Posted : 29 October 2012 07:42:01(UTC)
H0

Germany   
Joined: 16/02/2004(UTC)
Posts: 6,809
Location: Cologne, NRW
Originally Posted by: DaleSchultz Go to Quoted Post
Can someone explain what the problem is with using a grounded power supply?
With double isolation high voltage will only be touchable if two independent failures bridge both isolations.
With earthed power supplies, a single failure can bridge the single isolation - and the outside of the power supply and all the rails on your layout will have high voltage.
In old houses, there are sometimes only two wires going to the outlet (two pins connected in the outlet). If someone steps on an extension chord, one of the three contacts could be interrupted.

All these risks are a bit abstract IMHO. I never heard of someone getting a high voltage shock from touching a PC.
You are king in your own country (but if something happens, the insurance company might tell you something you don't want to hear).
Regards
Tom
---
Suaviter in modo, fortiter in re
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Bigdaddynz Offline
#11 Posted : 29 October 2012 08:25:18(UTC)
Bigdaddynz

New Zealand   
Joined: 17/09/2006(UTC)
Posts: 12,201
Location: New Zealand
One thing I did find with using a laptop power supply (Sony 19.5 vdc 4.7 amps) with a 60174 booster was that if there was a short circuit on the layout, you had to unplug the power supply from the mains for a minute or so then replug it to the mains before power could be restored to that layout section.
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