Power

I have made a few where I worked.

Mains power with three wire input. Hor, neutral, ground.

Plastic type fuse holders on the wall for each circuit.

You might include power lights for each circuit, mains power.

You could include small sockets to plug in a multimeter or make the meter part of it with a rotary switch..

Rich

Fans

If it were me building this......I would add a fan or 3 just to be on the safe side.

A place to get them cheap is a place called Skycraft in Orlando FL.  http://www.skycraftsurplus.com/

Heat, Derating and Surge

Cooling:

Absolutely!!!   Placing all of those supplies in one box will require cooling even if they are not fully loaded. Most MeanWell supplies, without fans, are specified for "convection cooling", but most of their spec sheets do not specify their actual test conditions. One old guide indicated that the supplies should be mounted to an aluminum plate in a one meter per second air flow (not convective cooling). So I would suggest fans pulling air in at the bottom and blowing up over the supplies. It would also be prudent to get finger guards / fan covers which include filters. Filters are cheep but will require a little maintenance and reduce dust bugs in the long run.

Derating:

At full load you will be loading the mains at 90% which does not leave you any real overhead. If available I would spilt the mains power between two 15 Amp circuits or use a 20 Amp circuit.  

Surge Current:

Your power calculation covers the steady state load but does not address the current surge when the power is turned on. If you look at the MeanWell specs you will see that the surge current is many times the steady state current. There are switches and circuit breakers designed to withstand repetitive high surge currents (generally expensive), but high currents can trip and even damage switches and circuit breakers. (Some 150 Watt MeanWell Switching Power Supplies can generate 40+ Amp turn on surge currents.) Again the solution is to power the supplies through multiple circuits. 

Additional notes:

You may want to wire a power indicator light on the output of each supply. It is a pain to have to dig into a box just to test to see if a supply is working.

Many MeanWell supplies have fuses on the Line mains input inside the case, but some do not. If the supplies do not have fuses you should add a fuse or breaker for each supply. Not being a trusting sole I usually add a double pole breaker to most of my power boxes.

Okay, cooling fans and bigger service

I can do both, cooling fans and increasing the power circuit size. I could run one 20 amp circuit but I would not be opposed to two 15 amp circuits. The startup requirements had not even crossed my mind. So, even though the steady full power state only requires 11 amps, I would be better off with more input power.

Does anyone have pics / part of suggested breakers, wiring for power lights, etc.? I could design it myself, but electrical stuff is certainly not my favorite part of this hobby. I like a real clean look... So, banks of lights on a panel would be preferred.

I did get some of these to tell me how much each booster is pulling, but I can not seem to get them to work correctly... Any wiring experts near Indianapolis?

multiple 15 amp transformers?

I would also suggest power

I would also suggest power switches to each component so you can turn them on individually as needed. That will save power and reduce the start up loading of your units. Check and make sure your wiring is up to the extra power. Some contractors often use smaller size wire than is prudent because it is cheaper. TURN THE POWER OFF FIRST! The wire size can be checked via an outlet if the cover is removed and the outlet pulled out of the box. It should not be hard to check the wire gauge.

Well, I just wanted it to be realistic

I mean heck, an electric melt furnace would be cool... LOL

Yes, I probably have more transformers than I need and there is a good chance that some will be removed.

I have 3 - 24 foot walls with two layout levels. LED strip lighting in white and color changing for each run. I figure that each level will consume 5 amps at 12 volts, so a total of 10 amps at 12 volts on each wall.

Digitrax recommends one power supply per booster, so that is close to what I ended up with. I have two 8 amp units and three five amp units and one 2.5 amp unit. Believe me, my "cheapskateness" has made me think about using one power supply on two boosters. I really do not know why I can't do that.

Do I need all of those boosters? I dunno...  I have them, so why not use them? I plan on having few to no issues with shutdowns due to shorts or overloads. If I could get away with just one DCS100 and sell everything else, I could certainly use the cash in some other investment.

I HATE most contractors !!!

Rob,

Good point. I hate most contractors for this very reason. Even in my custom home (I didn't build it) there are so many cheap features. I had exactly 1 (one) circuit in a three car garage and it was 15 amp with 14 ga. wire. Hmmm, gee thanks, jerks! I have since added a couple of 20 amp circuits with 12 gauge. The basement has the same cheap ole setup. Thankfully, there is plenty of room in my panels for new circuits.

So, I will probably put in 20 amp circuits in the basement too. I am trying to make layout startup free of checklists and resemblance of a Boeing 757 startup. Alas, I guess they have a complex startup to avoid the very same thing with overloading circuits, etc.

@ K

What do you propose as a mounting method for the power supplies onto the “box”?

Nick

good question

Nick,

I'm still experimenting with this one. These little brackets are made for Meanwell and I am sure I can get them to work with the Chinese knock offs.

Probably already covered

But some additional thoughts. Provide space for not only fans but same for exhaust/intake depending on orientation. Are you putting this another room? I sure would. You have a unit that has the potential to produce a lot of noise.......might be quiet but might sing like a soprano. There are lots of ways to do this and lots of good info in the replies. I sat in the middle of so many supplies during my career that my body hums at 60hz.........as I get older the voltage is dropping though.

Do I need all of those boosters?

How many engines do you plan to run at one time, and how much current do they each draw? For a 24' by 24' by 24' layout it seems that one command controller  and two  boosters should be enough based on length of power busses? .....DaveB 

3 is probably sufficient

Dave,

You're probably correct. I picked up my last DB150 at a show this fall really cheap. It works, so hey...

The helix and the staging yards were going to be on one booster, probably one of the eight amp ones since I would expect trains climbing the helix to be using some juice (sorry, didn't mention that with the layout dimensions. That is in the unfinished area of the basement, another 15x 20 or so. Then I was going to put the DCS50 in control of the engine facility, specifically, have it functioning as an auto reverse booster to handle the turntable and wye (I would run into problems if there were two trains in both areas). I picked it out of a garbage from a guy who had given up his hobby years ago ( you can't beat free, right?). He said it was broken but I haven't had any trouble with it. That will leave me the remaining DCS100s, one will be the command station/booster and the others.

One track is a double main. That could have 2-4 engine lashups on each track, many have sound. Then there could be one train on the return loop with 2-4 engines. There might also be a 1-2 engine switch job somewhere in the booster district. So, a maximum of 14 locomotives at any one time, during an operating session. Then there are two levels.

I have been VERY confused on how much power a sound loco actually draws. Anyone who can help me clear this fog will be my hero. I have heard that I need to plan on 0.25 - 0.50 amps per sound/dcc loco. The worst thing about an open house or an an operating session is having constant shut downs for one reason or another.

The unfinished portion of the basement is cool enough to chill wine and I will put the box in an unfinished wall without insulation. Overall, it sounds like I can cut my projected power needs WAY back... I am just trying to think down the road. I want layout lights, I want power for all of those extra little gadgets (switch machines, detectors, universal panels, etc.) AND, I want the ability to add lighting to buildings, street lights, etc. I have discovered SMD LEDs and they are so cool...

Digitrax recommends you use

Digitrax recommends you use one transformer per booster because they recommend you use their transformer which is under powered. The PS515 now the 615 would not be able to supply power to 2 boosters. They are at best I have found only suppling about 50% of the rated amperage.  Where as the transformers your using are very close to the rated supply. 

@ Rick S

Hi Rick,

Do you really use all that equipment to control your trains???  Is the layout a closet DC setup???

Nick

Input vs Output power

A few comments:

You've listed max output power for each power supply, not input power, and the input wattage will be higher due to inefficiencies. These are switching power supplies that are pretty efficient, but you still need to run your calculated draw on the input power, not output power.

I'd mount all the supplies on a plate, wire them up, and the mount the plate in the box. This is standard industrial practice - makes it easy to build & service.

I also agree with others that this seems like massive overkill. I'd suggest doing a detailed summary of what you think you really need, then add 50% or so on  to that. If you really need this much power, I'd consider splitting up the power supplies into 2 boxes, powered by 2 AC lines. Perhaps a box on each side of your layout? You're way too tight in terms of heat buildup and room in the box for wiring. And, as others have pointed out, you're likely to trip the breaker(s) with input surge current.

All that said, I commend you for askng the questions and planning this out.

Ray

Input vs Output power

As already mentioned Input power in amps is needed to determine the house line circuit breakers.

I am not an electrical engineer, but a little googling found this formula:

Input Current = Maximum Power / Efficiency / Power Factor / Minimum Input Voltage

As you can see there are actually three factors that determine the input current beyond the output power. The one already mentioned is the power supply efficiency, or how much input AC power is turned into useful DC output power, a common value is 80%. Higher efficiency supplies do exist, but unless your supply came with a spec sheet this is reasonable number to use. The second is power factor or the ratio of the real power to apparent power utilized, 1 is perfect, but switching supplies without active power factor correcting are typically .65. The third is line voltage, which can very by as much as +/- 10%, since the lower the voltage the more current required, we use a value of 103.5, 115 - 10%

So doing the math your four 12V supplies need about 13.4 amps, and your four 15V supplies need about 11.2, so two fifteen amp circuits would be advised. However, the 13.4 amps is probably higher that you would want to run a 15A circuit at continuously, but likely you will not be pulling 13.4 amps, you could always run a 20A circuit for those.

And as already stated your total power requirements may be over kill for you layout.

In-rush current, while is useful to note power supply manufactures should take this into consideration as in-rush current stresses the power supply components so should not be a concern on the AC input side of things.

Having individual switches on the power supplies may be useful for other reasons.

If you want to read the details of where I got the above information check out: https://www.spellmanhv.com/en/Technical-Resources/Application-Notes-HVPS/AN-21

Surge vs In-Rush and Ckt Breaker Selection

Scott, you are correct that in-rush is correct term. These days my fingers often get ahead of my brain when working at the computer.

K,

Selecting the correct breaker for an application is one of the most frustrating design conundrums an engineer faces, and I have reviewed too many design where the engineer(s) just punted. (Nothing like see a hospital bed under test emitting magic smoke.) Before selecting a breaker you should do the power analysis recommended by Ray and others. Once you have a good idea of the nominal and maximum currents, post your results and then we can try to help specifying appropriate breakers.

@amsnick

Sorta maybe actually no but that control room did a whole lot of work for the model railroad sound magician Jim Wells of Fantasonics.  After many decades that studio was decommissioned last year and now I can be found in my layout room fulltime! 

My head hurts...

Okay,

Yes, I'm most positive that what I have is overkill. BUT... I was trying to avoid not having enough power. Thank GOD I did not try to become an electrical engineer.

So, anyone have any recommended switches/lighting/fuses for the power supplies? I need to start building this box. I like the idea to build on a plate and then mount that in the box. It seems much easier.

I hadn't considered all the inefficiencies... See, I can do this wiring stuff, but I kinda hate it too. Sadly, no trains will run without it. So, I'll do my best.

List of supplies

Please post a list of the part numbers for the power supplies you intend to use and if possible which supplies you would want grouped on each circuit. I will try to come up with some suggestions.

Edit: And for what each supply will provide power.

One of those transformers is

One of those transformers is going to operate at max 70 deg c, 160 F. If you put all those inside that box, you will have issues. They need to be mounted, but not necessarily in an enclosure.

Those holes stamped into the covers of the transformers are for convective heat dissipation.

Do you have people around you that will actually touch the terminals, without checking for potential?

Make covers for the terminals if that is required.

This electronic equipment is designed to be useable with existing electrical service without any modification to the existing plant. ie; plug it into the wall. A wall outlet will have 16 amps of available power on a 20 amp circuit. A 15 amp outlet will have 11 amps of useable power available. What is the input power requirement for each unit?

I think Joe F. wrote an excellent piece on power districts, power supply and booster arrangements based on his own equipment power draw and his layout. His article is exactly what you need to read. I tried to find a link to his article, maybe it was a blog?, no luck. Perhaps No Such Agency will flag this for his attention and he will drop a link in this thread

Designing this yourself is great, know what you don't know, learn what you don't know and if you still don't know ask someone.

charlie in charleston 

Power Supplies are

Absolutely Incorrect::

The OEM power supplies pictured are designed and labeled to be installed in an enclosure. Manufacturers like MeanWell specify these supplies as COMPONENTS.

Per a typical MeanWell data sheet: The power supply is considered a component which will be installed into a final equipment.  

That final equipment manufacturer is responsible for designing the equipment enclosure, the Mains input and protection (Power Cord, Power Inlet Connector, Power Filtering, Power Disconnect (Switch), Overload Protection (Circuit Breaker of Fuse)) and much much more.

Needing those suggestions.

Ken and others,

Here are the mfg plates from both of the power supplies I will be using. There is the Meanwell brand which is going to be powering one booster each. The other one is from China and purchased off of eBay.  They will be used for a variety of accessory uses such as LED strip lighting for the layout and there will also be a BUS for connecting buildings, automobiles, street lights, whatever scenery items might need power as the layout develops.

These power supplies are supposed to be fused already, but suggestions have indicated that I need to have a power switch / fuse for the input and the output. It seem logical that rocker switches on the door (I am going to put in a hinged door) will work best, but I am open to suggestions.