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PWR56 Question
DaveB:
Question: Building a new layout. The room is 32x16. Will have 150 ft of main line with 3 passing sidings, a 26 ft 8 track switch yard and several industrial sidings. I have 1 PWR56 that was on our smaller previous layout. Will 1 PWR56 run this layout or would it be better to have a second one? Ring instruction manual says 30 ft max on 16 gauge bus lines, I will have longer than that. What would be the recommendation for wiring?
Thanks, Dave
nodcc4me:
32' is pretty close to Ring's specs. I would say try it with one PWR56 centered on the layout and check the voltage at the ends of the run. If it is low you can get another power supply and adjust the location of the first one.
G8B4Life:
It should work fine, Rings recommendation of 30ft is for 16ga wire. Go heavier gauge and you can run your bus longer. I know Bill runs longer than 30ft on his layout but I forget the length he said, and what gauge wire he used.
As Al mentioned, divide the bus into two halfway along and put the PWR-56 there, that way if the total bus length was say 100ft then each leg of the bus from the PWR-56 would only be 50ft long. If you had a really really long bus run you could get into ringing territory (http://www.lkorailroad.com/powering-the-lko-part-iii/) but I've no idea how long that is.
Another question to ask alongside is how many trains do you plan to run? the PWR-56 is only a 3A supply and it sounds like you have the potential to run quite a few trains at the same time.
If you were to go the route of checking the voltage at the end of the bus, you really need to have a load connected at the end to give a true indication of what the voltage really is when in use.
- Tim
Alan:
Your first concern should be capacity. On a layout as large as yours it seems likely there could be many powered units (locomotives, sound units, lighted cars, etc.) in operation at any given time. The first thing I would do is try to put a number on that. Estimate your maximum equipment requirement not your typical equipment requirement. From there you can estimate how much power is needed and thus how many PWR56 to use. This makes sure you don't run out of power at some random time.
Distance is your second concern. The rule is simple - longer wire runs require larger wire size. The PWR56 quotes 16 gauge because that is the maximum wire size its hookup terminals accept. There is nothing wrong with using a short (12") piece of 16 gauge as a pigtail from the PWR56 to hook to a bus that is of heavier gauge for the long wire run. This is how you would go about it if you utilize a single PWR56 on a large layout.
When you run the numbers I doubt a single PWR56 is going to be sufficient. Multiple PWR56 can solve both the capacity and distance issues. By mounting two or more PWR56 evenly distributed around the layout you get more power and it shortens the bus run for any one PWR56. This allows you to use smaller size bus wire.
PWR56 also act as signal repeaters so multiple around the room boosts the HC / LM signals. Potentially a useless feature in a 32x16 room. Have found no need for repeaters in my room of 28x32. In fact, I don't have a Ring power supply at all. Just HC and LMs.
Non-hobby power supply like mine is another option for you. I use a single 15V generic switching power supply (from eBay no less). To this I use a single 12 gauge bus around the layout (pic below). This arrangement has some nice attributes:
* Minimum number of components.
* Easiest installation.
* Less expensive and more powerful than hobby brand power systems.
* Single, easily accessed location for power supply. No crawling under the layout.
* Power supply can be upgraded to higher wattage if need arises with no change in wiring. Just swap out supply.
* 12 gauge bus has no practical limit on number of trains running simultaneously.
* Power is relatively uniform around the whole layout even under varying loads.The arrangement forces me to give up the power supply to HC reporting feature. But c'mon, how useful is that feature anyway? Here are two blog posts if you want to see my solution:
http://www.lkorailroad.com/powering-the-lko-part-i/
http://www.lkorailroad.com/powering-the-lko-part-ii/
Figure out your max trains and we'll help you from there.
Alan:
--- Quote from: G8B4Life on April 15, 2020, 08:26:03 AM ---... If you had a really really long bus run you could get into ringing territory (http://www.lkorailroad.com/powering-the-lko-part-iii/) but I've no idea how long that is.
- Tim
--- End quote ---
Tim makes a valid point about very long wire runs but don't lose sleep over it. I sometimes tend to go off the deep end with the electrical stuff only because it is my "other" hobby. Ringing is unlikely to present any practical problems except in rare odd cases. Besides, all DC power distribution systems, Ring or otherwise, are equally susceptible to ringing so if it happens, it happens. The brand of power supply makes no difference. There are easy fixes to suppress ringing should it occur.
Now if this were a DCC setup then yeah I would be concerned about ringing.
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