Randy:
In all the stuff I have read about setting up power districts I have yet to see any specific information as to what size layout should be divided into blocks. There are references to 'large layouts' and 'small layouts' but I have not seen a method of actually determining the point at which a layout should be divided up.
My layout will be 10' x 23' with a little over 500 feet of track. About 50% will be in staging and helices. I will power all accessories from separate power supplies. I will have a max. of three to four locomotives running at a time (one switcher and a consist) with a few others idling (if I can stand the noise). How many power districts do I need?
Thanks
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
rrinker Nothing in HO scale needs 4 or 5 amps to run, so limiting any given area of the layout to a lesser value is only prudent.
Nothing in HO scale needs 4 or 5 amps to run, so limiting any given area of the layout to a lesser value is only prudent.
Rich
Alton Junction
Yes, but 5 amps into 12 volts is 60 watts. Ever try to touch a 60 watt light bulb that was turned on? ANd considerign typical HO DCC voltage is actually 15V - that's 75 watts.
When my oldest was about 3 he wrecked by very nice Casio engineering calculator by putting ii in the lamp on the nightstand, which had a mere 40 watt bulb in it. By the time I noticed it in there, the plastic back had melted through. Now let 75 watts run through the plastic trucks of your loco.... OK, at full power it would trip the breaker, but only a slight loss in the wires, or if the loco wheels are firmly on the track, in the case of a derailment, it may only flow 4.5 amps, which won;t trip the breaker. 4.5 amps at 15 volts is still 67.5 watts of heat generated.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
rrinker Yes, you do not want to ever feed a 10 amp booster directly to the rails without some lower current circuit protection in between. And even 5 amps is iffy.
Yes, you do not want to ever feed a 10 amp booster directly to the rails without some lower current circuit protection in between. And even 5 amps is iffy.
Yes, you do not want to ever feed a 10 amp booster directly to the rails without some lower current circuit protection in between. ANd even 5 amps is iffy. It takes far less power to run any 'recent' HO loco than you might think, and if you break the layout up into logical power districts, each with its own circuit breaker, the total draw per section may well be far less than you think - if you've done the dividing logically, there will only be a few locos at a time in any given section. Not only does this prevent a derailment in one section from shutting down the entire layout and ruining everyone's fun, it prevents things like melted wires, decoders, and plastic bits.
One other thing. When I run a 5 engine consist, all powered, pulling 60 cars up a 2.6% grade on a curve, the current readout stays at ~1.8 Amps. This includes everything on the layout rails too. Basically this means the engines are loafing. I would like to try pulling the 60 cars up that grade with one or two engines to check the current draw, but the wheels slip. In theory it should be 1.8 amps too as that is the amount of torque it takes to move the load. ( Amps = torque )
Bottom line, you might not need as much track power as you think.
Think of it this way. If you have 20 engines sitting on your track, all with 1 Amp decoders, on the surface it would seem that you need a 20 Amp DCC system. But you won't be running all 20 engines at the same time ( at least I wouldn't ) and it's almost impossible to max out a decoder, let alone 20. A 5 Amp system would probably work and a 10 Amp system surely would. And you could divide the system into blocks and have a seperate booster and power supply for each.
I have already melted a couple of Kadee trucks with my 5 Amp system. A short with a 10 Amp system could be catastrophic. The DCC systems I have used automatically reset in about a second. I guess you could use fuses.
My overhead fixed lighting will be completely independent from anything ont he layout for a couple of reason. One is the one you gave, don't want to be stuck in the dark if a breaker trips because something failed on the layout. The other is that the pathway through the basement is the main way in and out of the garage - I never use my front door. I think the last time I actually entered the house that was was when the realtor was showing it. So while I plan to have all layout circuits switchable by a switch at the top of the stairs (with pilot light) so i can kill anything layout related from one point, I do not want the fixed room lights also controlled by that, so I can flip on a light, run downstairs to leave the house, or come home and flip on a light so I can see to go up stairs. I was planning to run 3 total circuits for the layout, one for the layout lighting (power supplies for LED strips), one for the rest of the layout (DCC power, structure lighting power, etc) and one for the workbench area. That should be more than sufficient to keep each circuit well under maximum permitted loads. I was also planning on more outlets than the minimum required to reduce or eliminate the need for extension cords while building the thing.
Here is the power supply I use:
http://www.ebay.com/itm/171816941910?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
It is fully adjustable with current and voltage clamps. I have it set for 4.8 Amps for my 5 Amp NCE system. The power supply trips faster than the NCE unit.
Keep in mind that all lighting should be feed from a separate breaker from your homes electrical panel. Maybe even two breakers. You don't want to be in the dark if a power supply pukes. Even wall warts can short out.
Hi Don:
Very good information. Thanks very much. I was pretty much guessing at how many LED strips I would need so this will help me sort it out a lot better.
All I'm trying to do at this point is figure out how much power I will need and how to break it up.
Thanks for your offer to help with specifics.
So, here's photos of my "sub-station" — warts and all!
Keep in mind that I am in the process of pulling new wire and making changes/improvements so you will see loose wire and open high voltage terminals.
I don't have time to identify each component right now but I will go back and edit this post as time permits and try to explain the purpose of each one.
This is all fed by the two 115 VAC power strips and those are wired into several "panic switches" which I have located around the layout fascia (from my old DC days!). Everything you see here is fed from one 20A. breaker off a 50A. branch circuit.
Cheers, Ed
Here's how I would do it...
Break it up into 3 supplies.
1 DCC specifically to supply the track (~14.0VDCC HO)
1 for accessories (12V + 5V + Ground Lines)
1 for LED lighting
Now how much lighting do you need? Well figure out how many 60 watt bulbs it would take to light your layout. Grab 3 of 4 INCADECENT bulbs above your layout, and line them up Adjust the space between them till you reach adequate brightness. You can figure out how many lights per foot you need.
Now a 60 Watt bulb puts out about 700 lumens. So now you can figure out how many lumens per foot you need. This will help you figure out if you need to double up on your LEDs (Some aren't as bright as others...so read the specs on lumens per meter or lumens per foot)
Next you know how big your layout is, and you can calculate the number of 60 watt bulbs your layout needs based on the bulbs per foot. (Draw it on graph paper if you have to)
A LED bulb is roughly 6'x more efficient then a traditional bulb. So 10 Watts will produce the same Lumen output as a 60 Watt bulb (same brightness) But you have to go through a power supply which is 80% efficient on average.
So lets say you calculate you need about 12 regular bulbs. That's 12*700 lumens/bulb = 8400 lumens total. This should help you figure out how much LED strip you will need to buy. (They rate them by lumen output)
12*60 Watts = 720 incandecent Watts total
720 / 6 = 120 Watts for LED equivalent.
Would I buy a 120 Watt supply? NO! That's running it at full tilt and that will wear it out early. I would run a supply at no more than 80% of what it's rated at. So...
120 / .8 = 150.0 Watts supply output total.
So I would find the closest power supply that is at least 150 watts output.
150 / .8 (for 80% power conversion efficiency) = 187.5 Watts pulled from the wall
[edit] made a mistake and fixed it between calculating power input and power output rating.
As a final note, please PLEASE look at the CRI # (Color Rendering Index) when buying LEDs. Aim for at least 80 on the CRI. That produces about 80% of the spectrum we are used to. The higher the CRI the better!
If you need specific design recommendations, please feel free to write.[edit]Here is a good website with recommended light levels for various situations. Unfortunately it's in lumens per meter squared. But it's a relatively easy conversion to total lumens. Multiple it by your plan area and you can calculate total lumens necessary.
http://www.engineeringtoolbox.com/light-level-rooms-d_708.html
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
Look at the thread from last week about blowign up power supplies with those LED strips. They take a lot of power. But this is amps at 12 volts - not amps at 120V, which, if the power supplies were 100% efficient, would be 1/10th - 40 amps at 12V is 4 amps at 120. More like 6 or so when you add in the inefficiencies in the power supplies, but still not taxing even a single 15 amp circuit.
Steve - I don't think those power supplies are for full NEMA racks, they'd need shelves or some sort of mounts as well, they are quite narrow. They'e meant to go in some sort of chassis, which may or may not be rack mounted. SO if they are palced in some sort of enclosure that prevents contact with the terminals, that would be more than sufficient. There's an AUssie guy with a YouTube channel, EEVBlog, does a lot of equipment teardowns and stuff, quite entertaining - one of the things he recently looked at was a 600V (!) 8 amp power supply, what uses 600V DC I do not know, but it was a 2U rack mount unit with effectively two power supplies internally paralleled to get the 4800 watts. Now this one needed phase AC input to run it - not only is it high power, it also is super precise. He got it for free - the company that bought it got a US spec model and tried plugging it in to AUssie 3 phase power (they use 240V there, not 120), and it promptly blew up. He tore it apart and found the blown components. Now that is a power supply - amazing build quality, also equally amazing price, many thousands of dollars.
hon30critter Randy: Thanks for pointing out that I had included the DCC power supply in my 12 volt calculations. It would be run off of 110 volts using its own power supply. Dave
Thanks for pointing out that I had included the DCC power supply in my 12 volt calculations. It would be run off of 110 volts using its own power supply.
For my 60+ Tortoises, I use a series of MRC Railpower 1370s, but regulated wall warts would work just as well. That leaves the issue of the LEDs.
Hi Stevert:
Thanks for explaining the proper housing for the rack mounted power supplies.
As Ed suggested, I am looking at power supplies that come with their own enclosures. The price isn't significantly more than the rack mounted ones, and they come with multiple output connections already built into the case. They are primarily intended for CCTV applications. This is one example that Ed suggested:
http://www.ebay.com/itm/18CH-Channel-Power-Supply-Box-for-CCTV-Camera-Security-Surveillance12V-10A-DC-/131000202272
In your opinion, is this a viable solution?
hon30critterMain lighting - 25 amps DCC - 6 amps Accessories - 10 amps _____ 41 amps total Am I totally out to lunch here?
OK you are talking about amps at 12 volts. LION would indeed use separate supplies for each level or zone of LED lighting. Ergo, stick with the wall warts.
12v Transformers at 25 amps would be VERY expensive, and not worth the effort.
Stick to the wall warts. You had it right the first time.
ROAR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS
What I wonder about in a situation like this is how to measure actual amps being consumed and at what point a breaker is being tripped.
While the situation is different, I had a toaster oven and a deep fryer on the same 15 amp circuit. Never had a problem running one or the other, but when we ran them both together, the breaker tripped. So, I rewired the circuit from 14 ga to 12 ga wire and changed out the 15 amp circuit breaker for a 20 amp circuit breaker and my problems were over.
When I added up the watts listed on the two appliances, the total was around 2,000 watts, as I recall. But is there a way to measure those watts (amps)? I just can't believe that Dave needs 40 amps for this purpose.
I don't think you're out of line with the calculations. Note that a 12V DC power supply is going to be too low to supply the DCC system, so you will need a different source there.
One thing you must definitely do - run multiple power busses with individual fuses/circuit breakers. You do not want 12V at 10 amps running everywhere - that's 120 watts and a short with some resistence can easily generate 100+ watts of heat without overloading the 10 amp supply. And if you've ever touched a 100 watt light bulb...
The LED strip lighting is a special case. You can conenct a few strips end to end, but at some point it no longe works since the current draw will cause too much voltage drop in the traces on each strip. This should be specified in the information for the strips. And I'd go half - if it says you can chain 4 strips, chain 2 and use heavy (#12 at least) bus lines to take power to the next set of strips, and so forth. It's the same concept as having a track power bus and feeders. I'd still use multiple power supplies and distribute them around, having the bus runs go out to both sides to cover the greatest area with the shortest wiring runs. Don't be tempted by higher current power supplies - they do make them, but I would not want to run everythign off a single 100+ amp power supply - not to mention when you get up to a certain level they end up needing 20 amp wall outlets and then eventually 3 phase power to run them. Relatively high current is unavoidable for the LED strip lights, but you should try to keep it in sensible chunks - also if all layout lighting ran from a single supply and that one failed..
For the on layout stuff, structure lights, Tortosies, etc - here is where the first thing after one of those hefty power supplies should be a board with multiple fuses/breakers on it, limiting things to an amp or 2 with multiple circuits. Things like building lights and Tortoises are generally wired with rather thin wire, since they don't draw much current. Thin wire will glow and burn if there are enough amps available, so the lower current fuses are there to protect the wiring and the layout in the event a short develops in one of the structures or under the layout. Just like power districts on the DCC side, this keeps the whole layotu from going down if a problem develops in one area.
hon30critter Specifically, I am asking if something like this power supply will work if I use four of them: http://www.ebay.ca/itm/321568555111?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
Specifically, I am asking if something like this power supply will work if I use four of them:
http://www.ebay.ca/itm/321568555111?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
Just an FYI, but those are rack-mount power supplies with exposed line-in connections rather than a socket/plug connection.
That means they have to be mounted in an enclosed equipment rack to meet applicable wiring/safety codes.
They look like they're 2U, so you'd need at least an 8U cabinet. Standard size is 10U, so probably something like one of these.
Of course, you could just hang them under the layout or something, but if you ever have a house fire (even if caused by anything else) and the insurance co sees those, they'll likely wash their hands and walk away...
Dave, I am neither a licensed electrician nor an electrical engineer, so I will leave it those who are more expert in this area to comment on your power requirements. But, given that cautionary note, let me make a few points.
Circuitron does comment on wattage by noting that a 1 amp power supply can control up to 20 Tortoises, so only 2 amps would be needed to power your 39 Tortoises. I agree that 6 amps is more than enough for your DCC command station. So, the remaining issue seems to be how much power you need to drive your layout lighting. But with 8 amps accounted for, another 32 amps (3,840 watts) for your lighting?
Regarding your 100 amp service panel, the total amperage of your circuit breakers can, and often do, exceed the service panel capacity. The key is the maximum number of amps being consumed at any one time. For heavy users of electricity, there will be an eventual need to upgrade the service panel and bring in a heavier line to your home.
Lion:
I do plan on using an electrician. Before I go too much further I have to find out if I can get another 20 amp circuit out of my panel, which is 100 amps total. I had the panel replaced a couple of years ago and I had the electrician install an additional 20 amp circuit into the garage. At the time I thought that would be plenty but now I'm not so sure. Anyhow, my days of working inside the fuse panel are over!
Thanks for the advice. It will be heeded.
Hi Rich:
It seems high to me too, and I'll readily admit that I don't understand the power needs as well as I would like to.
Here is the logic behind my calculations:
- Layout general lighting - I am going to use LED strips with 60 LEDs/meter. The layout is 24' x 10' on two levels. For the main level ceiling lighting I am going to use two parallel strips of warm white LEDs plus a bit more over the return loops, and I am going to run a single strip of blue LEDs around the layout as well for night operations. There will also be a single strip of white LEDs in the lower level which is all staging.
I calculate that the combined length of all the LED strips will be about 50 meters in total. If I understand the power requirements for the LED strips, each 5 meters requires about 2 amps @ 12 volts. That works out to 20 amps, plus a safety margin of 5 amps (25%) = 25 amps for the main lighting.
For the DCC system I am allowing 6 amps which is likely way more than I will ever use.
For the accessories like structure lighting, vehicle lighting, signals, street lamps etc., as well as 39 tortoises I am allowing 10 amps. If that seems high, keep in mind that I am an LED nut so I could end up with 300 - 400 LEDs on the layout.
Main lighting - 25 amps
DCC - 6 amps
Accessories - 10 amps
_____
41 amps total
Am I totally out to lunch here?
Thanks for your time.
Those sort of power supplies are used in all sorts of equipment. This is why there are ring terminals - you don't take a line cord and wrap bare or even tinned wire around those screws, you put on ring (and rings, NOT spade) connectors and put them under the screw. The screw would have to fully back out for any wire to come loose. And of course you unplug the thing before messing with any of the wire connections/ The dual outputs make it easy to run two seperate 12V lines wach with a more reasonable 5 amp fuse in it.
Most of the ones like that when new have a plastic shield that covers the wire connections to you don't accidently touch them. This comes off to access the terminals and should be put back in place for obvious reasons. The whole thing should be placed in a ventilated enclosure with a strain relief on the line cord and ideally a switch to turn it on and off, although just enclosing the terminal end is enough to prevent accidental contact. Think of a bus shelter sort of thing, or the covers over the third rail there in Lion's photo - the business end of the power supply slides under there which keeps fingers and tools from the exposed terminals.
I'd just build my own, but the parts to make a quality power supply cost more than you can buy these things for, let alone design and build time. These things are cheap enough to even keep a spare on the shelf in case one fails during a critical operating session. With my planned LED lighting, I'll need lots of amps at 12V to run it all - these things are just the ticket.
Amps, Volts... 10 amps at 12 volts is about the same as 1 amp at 120 volts (or something like that) Out on the poer pole, the fuses that isolate our property from the utility are 100 Amp, but that is at 4000 volts. Chop that down, and we have plenty of ampeers for our entire campus.
Primary Power Supply of LION provides 10 volts at 10 Amps. Runs 10 trains. Ameters show LION has snever used more than 3 amps, but him knew that knot when him specified power supply.
LION does have several power supplies for different reasons. But if you are using all of those LEDs for lighting, in the valance or elsewhere, those should be separate from the model power, and should be specified by your electrician. Stick to the model power, and you will not use all that much.
The reason for using LEDs for lighting is they draw so little power. If you are using 40 amps, then there is something that I do not understand.
Third rail (above) is 650vdc... each car has 700 amp fuses, and 10 cars there are, ergo 7000 amps per train, and maybe three or four trains on a particular circuit at one time figure 40,000 amps draw possible. (And there are almost 300 trains operating during rush hour!) That is a lot of power. I'd go on, but that would be political, and Mr. Steve would withold my wildebeest if I did that. Do not ditz with the third rail, and if you are really using that many amps, you need an electrician.
Back to your question, it seems to me that you could simply install a 50 amp sub panel in your garage and run separate circuits to each segment of your layout.
Dave, you should know best how much power you require for your layout, so I do not mean to appear to challenge your calculation.
But, to my mind, 40 amps seems incredibly high. As I am sure you know, 1 amp equals 120 watts, so 40 amps equals 4,800 watts.
I run a fairly large layout with 60+Tortoises, lots of signals and control panels, and an NCE PH-Pro DCC system, all off a 15 amp circuit including a dozen overhead fluorescent lamp fixtures.
Thank you for the detailed response Ed!
You have confirmed my concerns about the power supply that I posted the link to. The terminals are uncomfortably close together.
I had also looked at the CCTV power supplies with their enclosures, but now I understand the benefits of the way they are laid out much better. I also like the idea of being able to close them off with their included door panels.
I was aware of Rob Paisley's web site but I will spend more time studying it.
You have put me on a better path. Thanks.
Hi, Dave
I have visited Rob Paisley's site for reference of electrical circuits and diagrams often.
http://home.cogeco.ca/~rpaisley4/CircuitIndex.html
You may find some useful information there.
I have amassed many dozens of various power supplies in my quest for "electronic nirvana" on my layout. I have used some of the type you show in your link but keep in mind that many of these are not UL or CSA rated and may pose a risk due to poor quality or workmanship... however mine are still going strong but I only load them to about 50% since I do not trust some of the capacity claims.
The bad thing about these is that the high voltage terminals are right next to the low voltage ones and ARE exposed so you run the risk of shock, OR accidentally kicking 115 volts into your layout unless you put them into a secondary enclosure.
If you wire them CAREFULLY you're OK but a strand from the hot to either of the low voltage terminals will make things go poof real quick.
The terminals on mine are clearly marked: line, neutral, ground: + out, — out.
[edit] I see in the third photo on the ebay page in your link that this model has line, neutral, ground, two commons and two pluses so there is more distance, but still a bit of a risk if you don't protect those Hi Voltage terminals.
I bought one of these last year and it turned out that it would only provide about 25% of the stated capacity! Yet it gets 4 stars?
http://www.amazon.com/Pyramid-PS12KX-13-8-Volt-Power-Supply/dp/B0002JTD1Q
I put a 4.5 amp 12V light bulb on it and it tripped the overload. Amazon gave me my money back and said to keep the thing, we don't want it back. It works fine for my Tortoise power supply and the total current draw is about 2 amps.
I have found that closed circuit camera power supplies can be had at a reasonable cost and these are filtered and regulated and each output is protected with a quick acting interrupter and automatic reset. Many are designed with 12, 16, 24 or even 48 outputs at 12 VDC or 24 VAC.
I am not suggesting THIS exact one, but you can see the similar transformer, then the terminal strip and circuit protection, all in a nice enclosure. The nice thing, too, is that I can run individual circuits from this out to various areas of the layout and I trust that the current is stable and limited to about 1 amp each.
One of these would probably power your LED strips but you would probably have to wire one strip to each terminal, which really isn't a bad way to go.
These are just ideas that work for me... others, I'm sure, will have good suggestions, too.
Enjoy, Ed