DC 2nd Control station question

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Patrick

Well-Known Member
For those on DC, it's been too long since I've dealt with basic DC electronics, and I think I have it figured out, but...

I currently have on one DC control station hooked up, and the 2nd one is nearly ready. Does it matter that the 2 Control stations are reverse polarity of each other? The direction on each controller has to be different to have the same +/- on the same terminal. I don't think it does as they shouldn't technically be seeing the same block at the same time, and I shouldn't be running a train between blocks on different controllers. When moving a engine between blocks, both blocks should be on the same controller, correct? Other wise I can cause issues if memory serves. Just the first time I've been able to have two trains doing different things and I may be overthinking this.

Thanks in advance for any advice.
 

santafewillie

Well-Known Member
As long as he +/- on the two of them are correctly oriented, it doesn't matter. I hook both (-) terminals to the same common wire to all of the tracks. The (+) goes to the inputs on your selectors. I have never had an issue, but I don't normally run two trains at the same time.
 

Patrick

Well-Known Member
My big worry is feeding back across the second controller as they are of differing brands. There isn't a specific +/- on either one as the polarity changes when you change directions, at least on the meter they do. I guess I just need to hook them up and what's the worse that can happen? Temporarily blow the internal breaker?
 

Iron Horseman

Well-Known Member
My big worry is feeding back across the second controller as they are of differing brands. There isn't a specific +/- on either one as the polarity changes when you change directions, at least on the meter they do. I guess I just need to hook them up and what's the worse that can happen? Temporarily blow the internal breaker?
Is it possible to put an isolated section between the two with a DPDT switch on it to select which controller. Flip to controller 1. Move train onto section and stop. Flip to controller two. Pick up and go again.
 

dave1905

Active Member
I may be misunderstanding the question, but you can't hook two "control stations" to the same piece of track at the same time. I assume by control station, you mean a power pack or the controller that powers a train.

If you want more than one power pack, you need to have a control panel that has a DPDT switch for each individual section of track. The track has to be divided into sections, with insulated joints or gaps in the rails between each section. If you want to run two trains around a loop in the same direction and control them independently, you pretty much need a minimum of 4 sections. The track connects to the center of the switches and each controller connects to the side terminals of the switch. You throw the switch to select which controller you want to connect to that section of track. If you have more than two controllers, most people use a rotary switch to control each section of track.
 

dennis461

Active Member
Well, I guess I'll add on here since my layout has two controllers, DC operation.
First, you do not NEED two controllers unless you have an extremely long layout and voltage at the other end is too low to runs trains at the speed you like. Fatter wire may be called for to keep voltage drop at a minimum.

How long is the layout?

Now, my layout.
I had a shelf layout with my analog homemade voltage regulator throttle.
Next I built a turntable addition with a 18" radius loop in another room, it had an old Troller brand Autopulse throttle, analog with PWM at the lower voltage. I used this to test wiring and train operation.

When the turntable addition was ready, I moved it to the shelf layout and connected it to make one layout, but kept most everything as originally built/wired.

My layout has a common rail configuration, the other rail has blocks and SPST switches.
I added a SPST switch to connect the two separate main bus wires between the shelf layout and the turntable addition.
When this switch is closed, I can disconnect either throttle and run the entire layout with the remaining throttle.

When this switch is closed, I can keep both throttles connected AS LONG AS BOTH ARE SET FOR SAME POLARITY and run the entire layout with EITHER throttle. I can run a train at slow speed with one throttle and increase speed with the second throttle.

Now if the throttles are not set for same polarity, strange things happen. No train movement, or half speed operation. Luckily I have not fried any electronics and actually almost never have both throttles connected. My homemade throttle has a DC output OFF switch (DPDT) and I plan to add a DPDT and output fuse to the Autopulse.

Hope this helps.
IMG_4106[1].JPG
 

Patrick

Well-Known Member
Sorry I lost track of this thread...

I have enough power to run my DC trains around the loops, so to speak. I have an inner and outer loop with a couple sidings on the inner loop, of which one is a 5 siding yard. I have the outer loop insulated on both tracks at the switch pair on its own block and the sidings on another 8 blocks, isolated on one track with a common between all blocks. I'm using Atlas 215 Selectors for the block switching. Currently the outer loop "common" is wired to inner loop common for a total of 9 blocks. My goal was to originally be able to run a train on the outer loop one direction and do something completely different on the inner loop, but allow trains to move between the loops without major train moving.

My biggest issue is what dennis461 has pointed out that the two controllers I have have the direction settings completely opposite. At this point, I could make that work, but not with the way I want the trains would move. I have at this time everything working fine on one controller.

dave1905 and MHinLA: : I have isolated blocks already as I know you can't hook two power supplies across together with reverse polarity between them. Tends to make things go boom. Block train control isn't my major issue, but I think I have something figured out that might resolve what I'm looking to do. It's been way too many years since AF electronics and circuit design in general. That tends to happen when an electronics tech get into computers and goes a different route in life.

Thanks for all the responses.
 

trailrider

Well-Known Member
My biggest issue is what dennis461 has pointed out that the two controllers I have have the direction settings completely opposite. At this point, I could make that work, but not with the way I want the trains would move. I have at this time everything working fine on one controller.

Patrick - Reverse the leads to the track from whichever powerpack or controller is going the "wrong" direction. That should have your trains going the same directions.
 

MHinLA

Well-Known Member
Am I dreaming ? I seem to have explained this only a few days ago to, I think, another member or in a different forum !!
I'm not going to get into disputes with anyone else as I either can't understand it, too tedious, plain wrong. I'll stick to mine and be done.

I have never seen or known anyone, weather DC or DCC, who had 2 or more controllers/power packs/transformers running a layout ! The only exception is on huge layouts/club layouts where the RR has a division point/s.
On small/med home layouts there is no need to do this and is electronically wrong...We have 1, one powerpack which runs all the trains..If you have 2 or more you're chancing sending 13v x 2= 26v or more to an engine, frying the motor !! We just don't do that !
In analog DC we have one throttle such as an MRC Tech IV. The rails have blocks situated so as to have your longest train within 1 block...
Toggles are mounted in a panel where one has, say, 4 toggle switches/4 blocks. The toggles [spst] are simple on and off switches. The powerpack is connected directly to them in parallel, not the track. The rail gaps are on one rail throughout the system and they do not change to the opposite rail anywhere.. Each toggle has one wire to its own block, (between gaps). The other wire goes to the ungapped common rail.
One engine/train is sitting in a block. The block is turned off at the panel.. We can now run another train by turning on the block it's in and other blocks onward; just not the block the 1st train is in and turned off..And vise versa..The direction of a train is done right on the powerpack, as usual. The wiring up of this is up to you..There are several ways, with the same outcome..
DCC also has only 2 wires, but to the rails, not to toggles. And no longer is there any need for pesky blocks; which is the biggest reason DCC was invented ..M
 
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Bruette

Well-Known Member
My big worry is feeding back across the second controller as they are of differing brands. There isn't a specific +/- on either one as the polarity changes when you change directions, at least on the meter they do. I guess I just need to hook them up and what's the worse that can happen? Temporarily blow the internal breaker?
Patrick, I'm not an expert on DC power for model trains, but I do know a thing or two about electronics.

If you run both or more DC power supplies with the grounds connected as Willie recommends what you have done is to put them in phase with each other. That should, theoretically prevent any feedback.

If you run two power supplies of opposite polarity, what should happen is they will cancel each other out if the voltages are equal. If they are not equal the track voltage will be the difference in voltage between the two and the polarity will be of the same as the higher voltage power supply. I would think it may be possible to damage the internal circuity of lower voltage of the power supplies, especially electronic power supplies.

If the polarity of the power supplies are the same, no problem. The voltage will be approximately the same as the higher of the two.

As long as the +/- on the two of them are correctly oriented, it doesn't matter. I hook both (-) terminals to the same common wire to all of the tracks. The (+) goes to the inputs on your selectors. I have never had an issue, but I don't normally run two trains at the same time.
If I were you I would just follow Willie's recommendations.

This is why I love the simple wiring of 3-rail AC track!
 

santafewillie

Well-Known Member
I have never seen or known anyone, weather DC or DCC, who had 2 or more controllers/power packs/transformers running a layout !...On small/med home layouts there is no need to do this and is electronically wrong...We have 1, one powerpack which runs all the trains..If you have 2 or more you're chancing sending 13v x 2= 26v or more to an engine, frying the motor !! We just don't do that !
There's several reasons for having two power packs on a DC layout. One reason, as long as I run on one loop, my grandson can run on another loop without interference. If the power packs are properly oriented they can be run in opposite directions at the same time
 

MHinLA

Well-Known Member
There's several reasons for having two power packs on a DC layout. One reason, as long as I run on one loop, my grandson can run on another loop without interference. If the power packs are properly oriented they can be run in opposite directions at the same time
Yes, of course ! That's totally correct ! But you know what mean concerning the OPer ....
 

MHinLA

Well-Known Member
🌈 Patric, other DCers needing basic block control understanding. I edited it again today. Please see my edited/discombobulated/wrong instructions now corrected in post #13..Sorry for any confusion... M
 
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Patrick

Well-Known Member
My reasoning for the dual controller is the same as Willie's however, the grandson has his own layout next to mine. (N-scale)

I think I have it straight what I need to do

dennis461: I had read that article previously, but thanks for posting the link. I had though of purchasing the Tech 7 when I purchased my latest controller.

MHinLA: As long as the transformers aren't wired in series, you wouldn't be putting too much voltage against the load (motor in the engine). It was the canceling them out issue I'm overthinking, but will have time to look at it this long weekend. I really like the idea of DCC, but until we get the car paid off and then more on the house, I'm limited as too my available playtime funds.

Louis: There are times I really miss my Lionels.....👍

Willie: Thanks for the help you've given on this.
 

Iron Horseman

Well-Known Member
This is why I love the simple wiring of 3-rail AC track!
AC/CD doesn't mater. It is the CENTER third rail. Marklin HO & DC has always used three rail track for this very reason. They also continue to use it with their digital command stuff.

The old AC powered O-Scale outside 3rd rail stuff still had reversing loop problems.
 

Bruette

Well-Known Member
AC/CD doesn't mater. It is the CENTER third rail. Marklin HO & DC has always used three rail track for this very reason. They also continue to use it with their digital command stuff.

The old AC powered O-Scale outside 3rd rail stuff still had reversing loop problems.
That's two new things I just learned. :) Thank you sir!

That is I never heard of 3 rail DC or outside rail hot. What was the center rail? Was it both outside rails? Now I'm curious.
 




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