Voltage from two transformers

My new staging yard will have its own power supply. When a train crosses
from the staging yard to the mainline, there will be a split second when
it will draw power from both MRC units. Does voltage double up -- will
it be getting 24 volts for that interval -- and will this damage
engines? If it does, I suppose I'll have to coast across the insulated
joiners onto dead track, reduce the first throttle and then turn up the
second throttle. The mainline already has two MRC 2500 units, and each
block has a DPDT to determine which throttle controls that block. But I
didn't want to have to rewire my control panel to include the new
addition, so I gave it a separate transformer.
Reply to
harrym
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No, voltage is not additive in this situation. As long as the polarity is the same for both adjoining sections, and the voltage level is the same, you should see no difference. If the polarity is not the same, your engine will try to go in two directions at the same time, and could be damaged.
You would be far better off to wire in a DPDT toggle switch and create a transition block on the yard lead or to one of the yard tracks that can be controlled by both the mainline and the yard power, depending on which way the switch is thrown. That way there's no danger of getting your reversing switches crossed up... And you'll find that HO scale (and most other scales) locomotives don't coast well at all....
Reply to
gmcrail
If you're running fully independent supplies, the locomotive will stop because the supply and drain of the power aren't going to be connected. Use common rail wiring for best results. Better yet is to not do two different packs that each handle one area of the layout but rather switch between them depending upon what you are doing on a particular piece of track. A simple SPDT electrical switch will allow this for all of the sections (blocks) of your track.
-- Why isn't there an Ozone Hole at the NORTH Pole?
Reply to
Bob May
harrym wrote in news:ubednQr6tuJSg7_fRVn- snipped-for-privacy@news.ruraltel.net:
No, voltages in parrallal will not double. Voltages will double if they are in series.
In this situation the pack with the higer voltage will overwhelm the pack with the lower vaoltage. There is a possibility that this could dammage the power pack, but since these powerpacks are designed for some pretty rugged duty anyway.... I wouldn't worry. We do this sort of thing regularly on our layout. WE have an extension that is controlled by it's own throttle. The main layout has it's throttles. at the transition the locos are pulling from both. Been doing this for some time with no problems.
Reply to
Gordon Reeder
See my web page for one way of wiring DC.
Reply to
Terry Flynn
Terry Flynn replied: See my web page for one way of wiring DC.
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website contains a wealth of valuable information, Terry. Thanks for sharing.
Bill Bill's Railroad Empire N Scale Model Railroad:
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History of N Scale:
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Railroad Bookstore:
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to 1,000 sites:
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Reply to
Bill
When you are exhausted and fed up with having to be an electrical engineer in order to run your trains, come back here and find out about using DCC (Digital Command Control) instead. DCC is several orders of magnitude simpler and easier to work with. With three MRC packs, you've already spent as much as a DDC system would have cost you, and you still do not have the flexibility of operation you are looking for. For about the same money, and a lot less hassle, you could already be there. Don't stay stuck in the stone age of DC. There are far better ways to do things now. If you enjoy electrical engineering, then, by all means, engineer your heart out. But if you would rather spend your time operating your trains instead of having to figure out how to operate the track under them, come learn about the joys of DCC.
For starters, there is no need for a control panel. You never need to wire one and you never need to make any changes or modifications to one. How's that sound?
CH
Reply to
Captain Handbrake
IF the two transformers are "in phase" you will have 12V but double the current available.
IF on the other hand, they are "out of phase" (and you have a 50/50 chance of this happening at any given time), you WILL get 24 V., and let the magic smoke out of your equipment.
IMHO not worth the risk.
Don
-- snipped-for-privacy@prodigy.net
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Reply to
Trainman
Oops, My bad. You're talking DC, I was talking AC.
Don
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Reply to
Trainman
And you'll never have to learn how to figure things out. Quit basing your opinion on the higher level of allowable ignorance. I would ten times rather chase an open or short through a DC circuit than have to try to find it inside a non repairable chip. (Usually non replaceable too, buy new board, trashcan blown one.) You get to learn how to trash the old board, because it's cheaper to buy a new one than repair the old. Microelectronics can be wonderful where needed, but I don't think I'd want to risk a $1000 brass Pacific to the glitches of a ten cent chip. Don't tell me it doesn't happen, I've played with electronics far too long to believe it.
Like a model railroad that's "finished" and three months later "boring." And again elevates the level of allowable ignorance. "Don't think, buy."
Greybeard
Reply to
Greybeard
Captain Handbrake @ ACL.com wrote in news: snipped-for-privacy@news.east.earthlink.net:
I suspect that all the complaints about the cost of DCC fail to take its simplicity into consideration. By the time you buy all the little pieces, the switches and relays necessary to engineer a sophisticated DC controlled layout, you will almost certainly have as much money invested as the equivalent DCC and still not have all the benefits of DCC's simplicity and flexibility. Sure a DCC starter set is more expensive than a DC powerpack. But you have to look at the TOTAL cost (in both cash and lost sanity).
Reply to
Norman Morgan
What is it that you are risking?
What, "doesn't happen"?
Reply to
Paul Newhouse
harrym. if i've read this right and you're on standard variable dc control you risk blowing your power supplies or at the very least an internal fuse or circuit breaker in one or both of them. your locos should be ok. what you are doing is putting a short circuit across the difference in voltage between the two power supplies using the wheels of the loco. you could try and balance up the power supplies while running between the circuits but this is still very iffy and would need at least one decent centre zero voltmeter. a far better solution would be to put a suitably rated diode in both circuits. the lower voltage will then be blocked while the loco traverses the junction. there will be a small (400mv) drop across the diode in circuit but as the loco will likely be running at low speed across this section it shouldn't matter. please ask if any more help is needed. cheers michael
Reply to
Michael Wright
I have plenty of things to figure out without messing around figuring out things I dislike. So do plenty of the rest of us. Interest in electronics is like eating worms. A few people may enjoy doing it, most don't.
It has nothing to do with ignorance. I am quite good at electrical/electronic crap, I just hate doing it. So do many of us.
.....And I would rather shove needles under my fingernails.....
Fortunately, opens and shorts are extremely rare in DCC components, and the vastly simpler wiring required on the actual railroad is much easier to troubleshoot when you have done something wrong in construction. However, unlike conventional DC, once a DCC system is installed, you never have to do anything else to it. If it works when you turn it on it will work forever. Since it is so much easier and simpler to install, the likelihood that it will work as intended is much greater.
Hurrah for that!
I'll choose that option every time. And so will thousands of us that despise effing around with electronics. However, I do repair decoders that have been mishandled or damaged by their owners. Only friends though, I wouldn't do it for money or compensation. There isn't enough.
You said that, not me. I've never had any of those kinds of problems with my $1,000 brass Pacific since 1995, when I made the switch to DCC. I did have those problems in the stone age when an operator would over-run a block or throw the wrong switch or something similar.............
A specious argument at best. The interest is in the model railroad, NOT the electrical crap that makes it go. If it's boring because you don't know what you want, then how is farting around with wires and switches going to put the interest back in? Especially if you don't particularly like wires and switches? Engineering a new track plan or improving your operating scheme might do something, but having to face yet another bout of electrical torture in order to realize that is surely going to turn me off much quicker than changing some track around. Since I use DCC I can re-route and change my track daily, if I want to, with no thought given to the operating system that makes it all go. It just goes. I don't give a damn HOW it goes or WHY it goes. I only care that it goes. Switching from DC to DCC removed 99% of the frustration and hassle of model railroading for me. I can deal with the remaining 1% just fine. If you do not know how a real railroad is run, then DC will probably seem to be a perfectly fine system for operating the trains. If you really want to operate like real trains operate, then you need to remove the control from the tracks and put it inside the locomotive. DCC makes that possible with a minimum of fuss and no need to be an electrical engineer. If I had to go back to running A DC/block control railroad, I believe I'd just quit the hobby. It ain't worth it to me to go through all that crap.
CH
Reply to
Captain Handbrake
How about I don't care how a real railroad is run? Some of us just like to build models, structures, and scenery and watch the trains run :-).
Yes, with a few exceptions that is entirely correct.
But don't attribute a lack of interest in realistic operation to a lack of knowledge.
Reply to
Larry Blanchard
That's true, but not the thrust of my argument. You can't cover all possible interpretations in a few sentences. Someone is always going to see more there than you print, or extract a meaning different from the one you are trying to convey.
Now, if you don't care, then this is not meant for your consumption. You don't care. there's nothing wrong with that
I don't, anymore than I won't allow anyone to attribute a lack of enthusiasm for electrical/electronic workings to a lack of knowledge. For my part, there is no lack of knowledge, just an intense desire to avoid all possible contact with something I dislike very much. Others do not care at all for operations. We have two fellows like that in our group. They will go home before they will run a switcher or a local freight on operating night. Mainline through freight or passenger, nothing else. Suits the hell outta me. I prefer to run the locals and switcher jobs.
CH
Reply to
Captain Handbrake
When I became seriously interested in modelling US railroads, I went to a considerable effort to figure them out. I figured out that US society, industry and politics all influenced the railroads, so I figured out what those influences were - still am, in fact. How is that ignorant?
I figured out how to research how they how they did things, operated things, built things, painted things. How is that ignorant?
When I figured out I needed specific locomotives, cars and structures, I figured out how to detail, modify, kitbash and scratchbuild models to suit. How is that ignorant?
I figured out that in some cases I needed to produce my own scale drawings, so I figured out how to to that. When I figured I needed custom decals, I figured out how to design and produce them. How is that ignorant?
You seem to base your opinion on the idea that to be ignorant about electrical engineering is by extension to be ignorant about model railroading.
It isn't.
Model railroading is the sum of it's parts. For most modellers, the electrical/control part is not the main objective, merely a means to an end. As far as I can make out, you're an amateur electrical engineer who just happens to have a model railroad to absorb the output of the devices and gadgets you make. Which is great for you, but it puts you, I believe, in the minority. Most model railroaders, by definition, want to devote their time and energy to modelling and running their railroad.
Reply to
mark_newton
The least liked method of operating my friends DCC layout is using the DCC hand controller to operate turnouts and signals. That's one reason why most locations on my friends DCC layouts have control panels. They are easier to operate. For example to operate through the DCC hand controller requires at least 3 button pushes, a control panel requires 1. I have considered building a DC walk around controller to operate turnouts, using simple technology for my block control system. There is one yard were operation from both sides is an advantage. I could use either push buttons or an electric pencil method on the hand controller. The limit to the low tech system (no multiplexing serial communication) is the physical size of the hand controller and how many pins you have on your hand controller plug.
Reply to
Terry Flynn
Here is a point on which we can both agree. I dislike very much using the handheld to do anything other than operate the locomotive. This business of stationary decoders to operate turnouts and such is not a "feature" it is a nuisance. There is no substitute for being able to operate a turnout by hand or from a fascia-mounted control of some kind. I prefer manual operation of turnouts above all other. Remote operation from a central control point by a dispatcher is acceptable, but using the handheld to operate accessories while you are trying to drive a train is a pain in the arse.
Cheers, CH
Reply to
Captain Handbrake
Having DCC decoder control of a turnout doesn't stop you from having local electrical control or hand control of that turnout. Conflicts can be dealt with by having an electrical position switch on the turnout. My industrial module is wired for all three. Diodes on the output of the DCC decoders protects them from localized electrical switching and with the over center switch mounted on the linkage the turnouts can be thrown by hand.
I definitely agree with your last point!
Regards, Greg.P.
Reply to
Greg.P.

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