Need Some Electrical Expertice

[nachoman]

10 amp? Gee. You could charge a car battery with it

for a model railroad? that's about 10 old athearns at once, or 20 newer locomotives. That would be sufficient for a small club

[P5se Camelback]

Kool!

I'll have to get some down and dirty advice from you and Gary S. when the time comes.

I was a crackers Industrial Designer ... there wasn't much I wouldn't tackle and wrestle into submission ... but I can't see electrical or electronic and so it doesn't compute. When I first started at Sperry Corp., there was an office of three E.E. Circuit Designers on the other side of a 5-foot partition from the space that was my little group's design studio. Unless I stood next to it and looked over I couldn't see them and they couldn't see me (or later, my two guys.) But I could hear parts their discussions as they went about designing new leading-edge circuits for the next Main Frame Computer, the cabinetry design and interior component layout for which I was filling up sheets of maker paper developing concepts. But I wondered for several months why they kept talking about Gatorade all the time until I actually sat one day and really listened for about 20 minutes and came to the realization that they were really talking about ...


... gate arrays! :oops: :oops: :oops: :oops: :oops:

[BR60103]

At one NMRA DCC seminar, someone said that a power supply over 5 amps could probably do some serious damage to equipment in scales smaller than O, like welding switchpoints or melting trucks.

[P5se Camelback]

Well, not knowing how to identify a positive or a negative electron if they stood next to each other in front of me, can you step that power down? Or should I try to sell it (not knowing what it's worth - no box but looks brand new - I take care of my belongings!) on EBay?

Might this lump be a power source for A DCC system? I mean, I do know enough not to attach this directly to the raails ... it's not like I didn't (with some help) get a couple of DC cab-type layouts operating in my varied past!

At one point in the early '80's, The Prototype Circuit Board Shop at Sperry Corp was using double sided PC Board scraps to cook me up baords for some hand held throttles that I used the copy camera in the shop to shoot the artwork from a page in Model Railroader and the the guys would burn me as many of those little boards as I wanted. I built four of them.

But when it comes to all this power supply stuff and "putting components together" rather than purchasing an entire "turn-key" systen that I just have to hook up wires ... I leave that stuff to guys like Kevin and Gary ... fellas who do this electrical shananigans all the time!

[Gary S]

Remember: Just because the power supply can supply 10 amps doesn't mean it always will. The amperage flowing out of the supply is based on Ohm's Law: Current equals voltage divided by Resistance. The 10 amps wouold come into play only if the resistance was low enough to allow that much to flow. Of course, under a short circuit with very low resistance, the 10 amps could certainly flow through the short which could melt whatever was causing the short and possibly cause a fire. That's when you hope the supply has overload protection.

Sounds like the 10 amp supply would be great for uncoupling electromagnets. I would put a fuse in the circuit however!

[ezdays]

While we're all here and talking about this sort of thing ... I have ...

" 'Tripp Lite' Model PR-10b Powerverter 10 AMP Precision Regulated DC Power Supply."
Input: 117V AC 60 Hz Fuse Protected
Output: 13.8 V DC 10 AMP Fully Regulated Low Ripple...So now I'm wondering if there is a future for this twenty pound lump under the Lehigh Susquehanna & Western? :? :?:

Whaddya think? :?:

Just as long as you don't have to lug this thing around a lot, I think having something like this around is worth its weight. You can't get a lot of good power without it weighting a bunch. Think about it, if you had a three amp power supply and needed six amps, you'd be out of luck, but if you have a ten amp supply, you got power to spare. In my opinion, you can only have too big a power supply if you need the room and you don't need the power.

[P5se Camelback]

ezdays wrote:

"Just as long as you don't have to lug this thing around a lot, ... "

I used to lug that thing with me, along with the other pieces of the battery charging system, a box full of sets of different spring rates, final drive gears, extra sets of 2x3=6 batteries, sets of "matched" tires of different compounds, extra sets of wheels, extra motors, suspension parts, etc. .... and do it twice a weekend! It was like packing to go on vacation for a week, just for an afternoon of racing at some place an hour or two away!

It was fun ... but I don't miss it! I'd much rather sit right here and give myself a gloriously wonderful headache trying to figure out how to arrange a campus of industrial buildings in a specific area of a layout that to this point, only exists on a dozen or so pieces of canary yellow tracing paper! :mrgreen: Now ... that's fun!

But, back to the power supply ... must all 10 Volts come into play all the time in one application? Could you not somehow tap 3 or 4 volts for track power and 5 or 6 volts for uncoupling and the remainder for accessory lighting or whatever? Now I realize that might be a totally ridiculous, stupid, moronic, completely idiotic question, but I've already admitted to being clueless about anything beyond "green wire ground." :oops:

I ask this question armed with the vague recollection that the relationship between ohms and watts and volts can be shuffled/manipulated/modified with devices called resistors and capacitors and possibly several other such small, wildly important components of electrical/electronic circuits, and you end up with something taht magicall does what you need to have accomplished. It's just that I am a very visual kind of guy and not being able to "see" electrical impulses flowing through wires, it's all Latin to me!

[nachoman]

You can always put a smaller fuse downstream of a 10A supply. The danger is, if you have a short, 10A is enough to do a fair amount of damage. If you put a 5A fuse downstream of there, any current draw over 5A will blow the fuse, protecting you remaining circuitry from further damage. Think of it like the electrical system in your car. Let's say your alternator supplies 50 amps when the car is running. And let's say you have an accessory that draws 3 amps. The manufacturer designs a 5 amp fuse for that accessory's circuit. That way, if there is a short circuit, no more than 5 amps of current can flow through that wire until the fuse blows. If there was no fuse, the full 50amps would try to run through that wire until it melted the wiring harness and potentially caused a fire. You don't want the same thing to happen to your trains. If a DCC manufacturer says 5A max, that means the electronics can handle no more than 5A. If there is no fuse in the system and you forget to take one of those track gauges of the rails...

[Gary S]

But, back to the power supply ... must all 10 Volts come into play all the time in one application? Could you not somehow tap 3 or 4 volts for track power and 5 or 6 volts for uncoupling

did you mean to say amps?

[P5se Camelback]

Gary ... one more time ... I don't have a clue what I am talking about when it comes to electrical/electronics.

I couldn't tell you the difference between an ohm, a volt or a watt ... or even Gatorade ... er ... gate arrays, whatever they are/it is! :? :?

However, if you want to talk high pressure injection molded part design, or argue the economics of molded plastic/structural foam cabinetry parts vs. formed steel cabinetry parts ... bring it on, your butt is mine!

[ezdays]

Ten amps (not volts) is simply ten amps. Any load put in parallel with the others will increase the current drain by a little or a lot depending on what it is. Sometimes a device can inject a bit of noise (unwanted signals) on the power supply that can affect other devices being powered by it, but for the most part, you can divide the ten amps up to power various devices as you wish. Remember though, an overload on one will affect the others and pulling the maximum power from any supply will not only stress it, but tend to generate a lot more heat.

Also, powering a low current drain device with a large output supply could cause a few problems. Let's say that you have a device that draws 500 mA (1/2 amp), and so you use a one-amp supply. A problem with the device could cause the current drain to increase, but the current is limited with the one-amp supply so as not to cause too much damage. Using a ten-amp supply would allow a much higher current drain to occur, probably cooking the defective device beyond repair. The above suggestion by nachoman of using branch fuses to each device to prevent this is a good one.

[jim currie]

Gary ... one more time ... I don't have a clue what I am talking about when it comes to electrical/electronics.

I couldn't tell you the difference between an ohm, a volt or a watt ... or even Gatorade ... er ... gate arrays, whatever they are/it is! :? :?

However, if you want to talk high pressure injection molded part design, or argue the economics of molded plastic/structural foam cabinetry parts vs. formed steel cabinetry parts ... bring it on, your butt is mine!

P5se do your self a favor and pick up a copy of "UGLY'S electrical reference" has a lot on useful stuff in it , simple explations and a lot of useful tables in the back.
jim

[P5se Camelback]

I don't know that I'll ever get it! Now Don, in a very kind attempt to explain, has introduced a fourth word into the mix! Now we have Ohms, Amps, Watts ... and Current. I read Don's post three times and the only thing I can tell you is ...

Do you remember what the parents sounded like in the "Peanuts" cartoons? "Whaa whuh whaaa whaa wa wa," like a trombone, sorta.

it took me several years to figure out how to not have a short when I threw a turnout to the "other" route on that 4'x8' "platforn" I had as a pre-teen/teenager! I was in my 40's when I finally understood the DC thing well enough to wire my hand laid turnouts with isolated route-dependant live frogs ... I'm sure that's not the correct term, and I can't remember the right one at the moment, but you know what I mean. [And the truth be known, I had a Kalmbach "How to Wire ..." book opened to the right page while I wired up the first couple. Now I can wire them without the book.]

I feel like some sort of village idiot sometimes, but I just don't get electrical/electronics! I mean, I actually feel pretty good about myself if I install a new special IC-controlled switch for the ceiling fan where there was once just a regular light switch ... and it works ... first time, and doesn't blow a breaker!!!

I actually took photos of the engine bay of my project car with about 30 close-ups of connections, because I don't know what it is or what it does, but if I can see the way it was wired up before, I can wire it up again. On the other hand, I had no trouble building the engine, checking ring and bearing clearances and torquing the crank main bolts and the head bolts down to spec, and all that stuff! (It has a 280-degree duration camshaft ... it's a loper at an idle, but comes on really strong when you step on the loud pedal!) I had an SCCA friend come over and install the new wiring harness - I pinstriped his Harley as payment.

When the time comes, I'll find someone to come over and help me wire and put power to my layout, especially if I eventually spring for DCC!

Seriously ... thank you, Don ... I know you were trying to help! We all have our areas of expertise and then there are the things best left to someone else ... well, I can design damn near anything (I may have to do a little homework first if I've never don aanything like it before,) I can build all kinds of stuff, but I generally don't mess with anything beyond wiring positive/negative/green wire ground ... other stuff I leave for others who are more qualified.

[nachoman]

Another good source for power supplies is your local thrift store - if you know what you are looking for. I saw a 13.5V DC, 5A power supply that came from some kind of a wine bottle chiller - they wanted 6 bucks for it (comes with the wine bottle chiller ) They usually have wall-warts aplenty, and various power supplies that went to battery chargers, electronic games, and electric appliances.

[P5se Camelback]

I'll bite ... Wall Wart ... that is one of these little power supplies like the one that powers a really cool lamp that I have ... it's a 1 1/4" x 1 1/2" x 2 1/2" black thing with a two spade connectors at the end of a long black cord that plugs into the lamp which uses an High Intensity lamp.

... and I guess my original question here was can you step down 10 amps to something lower that is safer to use?