# Power supply basics?



## Cap'nBill (Dec 27, 2008)

I've been looking at "transformers, power supply, & controllers" and don't understand what's needed. I have a little Bachmann' transformer',which never worked properly, and wanted to upgrade to run a couple of engines, a few accessories. I see some of these items.....as on eBay, have two parts: what seems to be labled 'regulated 12v or 24 v , 10Amp, or 13Amp etc. power supply: AND, a transformer...controller or whatever is the proper term. Prices of course are all over the board. Do I need a regulated power supply? What does it do ? My smaller..N guage, I have a 'transformer' or is it a controller, and plug it in the wall. My guess is this time of year, there are some other new guys trying to figure this out. Looks like one can spend from $20 to $500........


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## Totalwrecker (Feb 26, 2009)

Check out MRC and see what they have. I think you just need more power -Amps- not a more sophisticated control system. 
Once you know the terms and descriptions from a manufacturer, then you can venture into ebait. 
You might find what you like there and get a valid warantee with it. 


John


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## Greg Elmassian (Jan 3, 2008)

First, the term "transformer" is used very generically, so you just have to kind of ignore that term. 

Sounds like you are running track power. No, you do not need a regulated supply. 

There's sort of 2 ways to go, one way is the power supply, and the "throttle" all in one unit. It provides DC and a way to vary the output level. 

Then you can also buy a power supply and a "throttle" separately. 

An advantage of the latter method is that it's easy to use that power supply for something else later, like track powered remote control, Aristo Revo, Airwire w/track power, DCC, MTH's DCS. 

But power supplies are basically very inexpensive nowadays, owing to the technology of a "switching" power supply, like the itty bitty power supplies for most of your electronic gadgets. 

There's an older, tried and true technology for making a power supply with a variable output, and it's a lot more costly to make, so that's where your $500 power supply comes from. 

Does it make a difference? I can only think of a few specialized cases where it is NEEDED, but this will open a hot debate. For what you are talking about, an inexpensive power supply and an Aristo 10 or 15 amp "throttle" would be fine. 

(remember, having the capacity to handle 10 or 15 amps does not REQUIRE that current to be flowing all the time, just like having a 150 mph car, you can drive it slower!) 

Now in terms of amps, volts, you should have about 24v to be able to handle various different locos, though most of the time you will be running between 12 and 15 volts.. amps? 10 amps max serves about 99% of the people in this hobby. 

Hope this helps, 

Greg


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## krs (Feb 29, 2008)

Posted By Greg Elmassian on 25 Nov 2010 09:29 AM 
There's an older, tried and true technology for making a power supply with a variable output, and it's a lot more costly to make, so that's where your $500 power supply comes from. 

Does it make a difference? *I can only think of a few specialized cases where it is NEEDED*, but this will open a hot debate.


Greg,

I don't want to start a hot debate, but you realize of course that making such a statement begs the question - for what application in Large Scale model railroading do you think a traditional power supply is NEEDED and where a switchin supply cannot be used?


Regards,

Knut


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## Nicholas Savatgy (Dec 17, 2008)

Posted By krs on 25 Nov 2010 10:57 AM 
Posted By Greg Elmassian on 25 Nov 2010 09:29 AM 
There's an older, tried and true technology for making a power supply with a variable output, and it's a lot more costly to make, so that's where your $500 power supply comes from. 

Does it make a difference? *I can only think of a few specialized cases where it is NEEDED*, but this will open a hot debate.


Greg,

I don't want to start a hot debate, but you realize of course that making such a statement begs the question - for what application in Large Scale model railroading do you think a traditional power supply is NEEDED and where a switchin supply cannot be used?


Regards,

Knut


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## Greg Elmassian (Jan 3, 2008)

DCS, from the mouths of the people who I consider experts. I have some experience with DCS, not years of it, but I have been exposed to every major issue that I have seen the experts address, and I believe them when they talk about highly filtered "pure" DC.... 

Also, if I was running track power with the Aristo Revo system, I'd want to try a nicely filtered analog supply and try not to buy $20 capacitor boards for every loco as recommended by Aristo. 

Regards, Greg


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## krs (Feb 29, 2008)

Posted By Nicholas Savatgy on 25 Nov 2010 12:12 PM 












Cute


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## Nicholas Savatgy (Dec 17, 2008)

Sorry, But its Thanksgiving

I thought i'd give.......HE HE HE


Just joking, But weve been down this power pack Road so many times.................


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## Cap'nBill (Dec 27, 2008)

Thanks, Greg, for the explanation! I guess while 'we've been down this road'.....if it weren't for some new guys, or new equipment, why bother having a forum? Bill


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## Greg Elmassian (Jan 3, 2008)

No problem, if you don't mind getting advice from a nasty know-it all, ha ha! (sort of inside joke about myself). 

Sometimes I don't have the steam to get into the which is better debates every time, but this is a very reasonable question that hits every new guy. 

There's a lot of misinformation out there, and I benefited greatly when I started in the hobby from people like George Schreyer, just the facts, no fluff or hidden agendas. 

Regards, Greg


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## Dan Pierce (Jan 2, 2008)

I would like to add, see if a power supply has the linear (pure DC) output capability that some locos/sound systems need to function properly. 

Most of the set and inexpensive locos I have seen do not care, but LGB mts and sound units do care about the power. 

You can always ask here on the forum about a particular engine/sound unit. 

Another comment is older standards were 20 volts or less, fancy electronics now being made like 24 volts as Greg already mentioned. 

Aristocraft passenger cars do not like 24 volts, lights will burn out quickly. LGB used 18 volt smoke units in some engines. 

MRC to this day has a 21 volt rating on decoders, most work on 24 volts, but could burn up. 

So, always read the specs and raise questions here.


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