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DCC power supply

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DCC power supply
Posted by westaus64 on Saturday, April 11, 2009 4:58 AM

I would like to build my own power supply for my DCC controller.  Can anyone help?

Tags: Digitrax
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Posted by mfm37 on Saturday, April 11, 2009 5:46 AM

 You are probably not going to like this answer but here goes.

A DCC power supply requires a transformer. Hooking one up will require connections to potentially lethal house power connections. Quite frankly, if you need to ask how to do that, you will be safer purchasing a ready to go power supply. In the US, we're talking a $35-$45 dollar investment to continue enjoying our trains instead of worrying about electrocution of ourselves and/or our loved ones.

 Martin Myers

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Posted by mobilman44 on Saturday, April 11, 2009 8:06 AM

Hi!

I've been playing with trains since the '50s, and am very familiar with electricity (not electronics), having done a bit of house wiring and several electrical projects over the years.

My strong advice is, unless you have the needed knowledge & skills, I would not attempt to build a power supply for fear of getting shocked - or posing a fire hazard.  Besides, I doubt you could build a power supply as good as a manufactured one for the same money.  Excellent 5 amp PS are out there in the $45 range, and they will serve you well - and safely.

If you have the bug to build something electrical, try one of the many DCC projects out there that will add to your layout and make it truely unique.

Sorry to sound so negative, but having been knocked on my butt from my electrical experimenting, and been through a house fire (the cause not connected to electrical stuff), I am pretty cautious on the subject.

Hey, ENJOY!

Mobilman44  

ENJOY  !

 

Mobilman44

 

Living in southeast Texas, formerly modeling the "postwar" Santa Fe and Illinois Central 

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Posted by MisterBeasley on Saturday, April 11, 2009 8:47 AM

Another vote for buying one.

If you do want a good project to get your feet wet in electronics construction, build a capacitive discharge circuit to run your twin-coil turnouts.  But, don't turn it on with wet feet, OK?

Besides electrocuting yourself or burning the house down, you could also fry your DCC system if the power supply malfunctions.  That's by far the most likely outcome.

I graduated from MIT.  When I needed a power supply for my Lenz system, I went to my LHS and bought a 5-amp NCE unit.  Not that I couldn't have found a circuit online, gone to Radio $hack and bought the parts to build one, but the NCE box is better and cheaper than doing it myself.

It takes an iron man to play with a toy iron horse. 

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Posted by Phoebe Vet on Saturday, April 11, 2009 9:19 AM

A)   Welcome to the forum, and don't take the negative answers personally.  You are getting well intentioned advice and no one thinks less of you for asking the question.  Sometimes people are trying to keep you from making the same mistake they made years ago when they didn't have anyone to ask.

B)   That said, I am a Navy trained electronics technician and I also advise that if you have to ask the question then you probably shouldn't do it.  The failure of a 30 cent component could potentially fry your $200 - $500 DCC command station.  It's much better to buy a commercial unit that is UL approved.  They are not expensive.

Dave

Lackawanna Route of the Phoebe Snow

  • Member since
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  • From: Enfield, CT
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Posted by Doc in CT on Saturday, April 11, 2009 9:42 AM

 Another vote for buy.  Tony's Trains has a 6amp UL listed three wire unit for $40.  Comes in a nice plastic case. And comes with installation instructions.

BTW  power supplies run hot (60C or 140F so keep it ventilated (ditto on command units).

Co-owner of the proposed CT River Valley RR (HO scale) http://home.comcast.net/~docinct/CTRiverValleyRR/

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Posted by cacole on Saturday, April 11, 2009 10:18 AM

 I've built power supplies in the past for different projects, and am of the opinion that you're better off purchasing one.  Locating a suitable transformer and other components is going to cost more in the long run that a ready-made power supply.  Unless you have extensive electronics and electrical knowledge, selecting the wrong transformer can be hazardious to your health, your DCC system, and your house.

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Posted by westaus64 on Sunday, April 12, 2009 9:06 AM

Thanks for the reply.  It appears to be the best thing is to buy from all the comments.  I am a retired Communications Technician and started training back in 1959 in Australia. Wiring is not the issue, it was the satisfaction of building it myself. 

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Posted by jbinkley60 on Sunday, April 12, 2009 10:00 AM

westaus64

Thanks for the reply.  It appears to be the best thing is to buy from all the comments.  I am a retired Communications Technician and started training back in 1959 in Australia. Wiring is not the issue, it was the satisfaction of building it myself. 

Here's a project I designed that you may want to consider for some fun and added functionality.

 http://www.thebinks.com/trains/decoder_adapter.html

 

 

 

Engineer Jeff NS Nut
Visit my layout at: http://www.thebinks.com/trains/

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Posted by mfm37 on Sunday, April 12, 2009 10:23 AM

Well if you are not afraid of the wiring and just need some specs, here goes.

You will need a suitable transformer with an output a volt or two above the desired track voltage (you didn't mention scale) . You don't want too much extra voltage because that will have to be dissipated as heat by the booster. The transformer should also be capable of delivering a higher current than the booster's limits. More current is OK in this case. 6 amps for a 5 amp booster would be enough.

Use a fuse on the input and also on the output side. Again, the size of the fuse will depend on the size of your booster. For a 5 amp system a 5 amp fuse on the output should do the trick. You want to match the output fuse to the booster's output.

Use ohm's law to determine the input fuse size. e.g. output is 5 amps at 16 volts = 80 watts. You'll need an input fuse that works out to a little over 80 watts depending on your input voltage.  Mount the whole works in a suitable enclosure so that there is no access to the high voltage side of the transformer. Don't forget to leave some cooling holes. Ground the transformer frame and the enclosure (if metal) to house ground. You can ground the booster to house ground but do so only at one point if you choose to do so. This is reccomended as the home made power supply will most likely not be double insulated as with many of the manufactured power supplies.

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