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DCC questions

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DCC questions
Posted by ROBERT OLEJNICZAK on Monday, April 09, 2018 5:35 AM

I have a layout room size is 18x 25. What size wire should I be using 14awg or 16awg for my DCC system. I also have a Walthers 933-3171 turntable 90' can this run on DCC if I hook the wires into the main bus for the track and a auto reverse. I understand the table has to run on dc to turn. Please let me know. Thank you 

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Posted by mlehman on Monday, April 09, 2018 10:27 AM

I'd go with the 14 AWG for the main bus. If you're likely to be the only operator or one of just a few, 16 AWG could work, but runs those lengths are likely to be will benefit from the fatter bus. For drops from the track to the bus, 22 AWG will work for short lengths 3' to 4 feet, but you may want 18 AWG for longer paths. You can't use the larger sizes to the rail in HO, so you need to plan on stepping down to smaller AWGs as part of your planning.

You can set up a TT motor to drive like a loco motoer off a DCC board. The output will be DC for the TT motor, but you can feed and control it via DCC. Thoese are general ideas, as I've not had any specific experience with the Walthers TT. If Auto reversing is built into the TT, it may function without a need for an autoreverser, as adding one of those may confuse things if the TT has built in reversing. There are several threads here on the Walthers TTs that a Search will turn up and be useful to you.

Mike Lehman

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Posted by MisterBeasley on Monday, April 09, 2018 10:50 AM

Welcome aboard!  Welcome

There is a separate sub-forum here for "Electronics and DCC" and topics like yours are usually found there, and will generally get more responses.

As a new member, your posts will be "moderated" for a short while, so don't be surprised if your posts don't show up immediately.

It takes an iron man to play with a toy iron horse. 

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Posted by ROBERT OLEJNICZAK on Tuesday, April 10, 2018 7:20 AM

Do you think I should use stranded or solid wire?

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Posted by DigitalGriffin on Tuesday, April 10, 2018 9:27 AM

Need more information:

1.  What is the furthest distance from your booster to your furthest track from the booster.

2.  What kind of current will you be running?

Let's take your worse case scenario and run 43 Feet and 3 amps from the booster.

A #10 wire will give you a <2% drop in voltage.

Now lets break your layout into 2 boosters, your worst run would be 21 feet @ 2 amps.  You get a <1.6% drop in voltage with #14 wire.

But even IF you ran 21 feet @ 3 amps on #16 Wire, you would have a .51V drop or 3.51% which is marginal, but acceptable depending on adjoining districts.

http://www.calculator.net/voltage-drop-calculator.html?material=copper&wiresize=13.17&voltage=14.4&phase=ac&noofconductor=1&distance=21&distanceunit=feet&amperes=3&x=28&y=19

Ideally you want to keep voltage differences between districts to about <.1 Volt.  But that adjoining district also has a voltage drop associated with it.  So lets say district 2 as 13.9VDCC due to voltage drop, and district 1 has 14.0VDCC due to voltage drop.  14. - 13.9 = .1 which is acceptable.


I successfully run 16AWG but I run a lot of wires in parallel every couple feet.  This allows for a minimal voltage loss and also allows for more current, and more flexible runs.  It also keeps the bus wire closer to branches.  As I have buildings and animations toward the center of the table, running additional wires for the track power just made "sense".  But it's additional work.  My power supplies also sit in the middle of their districts, so it cuts the run length down in half.


Don - Specializing in layout DC->DCC conversions

Modeling C&O transition era and steel industries There's Nothing Like Big Steam!

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Posted by DigitalGriffin on Tuesday, April 10, 2018 9:32 AM

ROBERT OLEJNICZAK

Do you think I should use stranded or solid wire?

 
Solid for feeders.  Stranded for bus.  Stranded keeps is flexible.  Solid makes it easier to solder to track.

 

Don - Specializing in layout DC->DCC conversions

Modeling C&O transition era and steel industries There's Nothing Like Big Steam!

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Posted by BigDaddy on Tuesday, April 10, 2018 9:50 AM

Dan beat me to it.  Move along folks, nothing to see in this post.

Henry

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Posted by mbinsewi on Tuesday, April 10, 2018 9:56 AM

If you use the "suite case" connectors, don't you need stranded on both ends?

I've never used them, I don't know.  My bus is solid 14ga, feeders are solid 22ga., and I strip small areas of the bus, wrapped the feeder, soldered, and taped the connection.

Mike.

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Posted by SpaceMouse on Tuesday, April 10, 2018 10:30 AM

DigitalGriffin
I successfully run 16AWG but I run a lot of wires in parallel every couple feet.  This allows for a minimal voltage loss and also allows for more current, and more flexible runs. 

I think this answers a question I have but I'm not sure. Does additional feeders reduce voltage drop, or are you saying you run parallel bus lines?

Chip

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Posted by DigitalGriffin on Tuesday, April 10, 2018 11:25 AM

SpaceMouse

 

I think this answers a question I have but I'm not sure. Does additional feeders reduce voltage drop, or are you saying you run parallel bus lines?

 

 

In essence, yes.  I run my bus in a circle around my layout and every couple feet bridge one side to the next.    To show you what kind of difference it makes, run that little voltage calculator I showed you, and cut the current in half.  This is because 1/2 the current is going down one leg, and 1/2 the current another.  (Rough estimate).  Your voltage drop is half.

However you need to do some linear algebra if you want to find the true current and voltages across each bus line.  https://en.wikipedia.org/wiki/Kirchhoff%27s_circuit_laws



I run my bus in "boxes" about 4'x4' in dimension.  That way I'm never more than 2' from a bus line.

Don - Specializing in layout DC->DCC conversions

Modeling C&O transition era and steel industries There's Nothing Like Big Steam!

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Posted by gregc on Tuesday, April 10, 2018 11:44 AM

DigitalGriffin
This is because 1/2 the current is going down one leg, and 1/2 the current another.  (Rough estimate).  Your voltage drop is half.

across the short distance between the two feeds (which may be neglegible).   But it is no difference across the presumably longer length they have in common

greg - Philadelphia & Reading / Reading

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Posted by DigitalGriffin on Tuesday, April 10, 2018 12:26 PM

gregc

 across the short distance between the two feeds (which may be neglegible).   But it is no difference across the presumably longer length they have in common

 



If you run ring busses like I do in boxes, your statement is incorrect.  It will make a big difference over a long run.  (or am I reading your statement wrong?)

Even if you ran two parallel feeds with no ring bus, as long as there are two independent leads to the booster, then my statement is also correct.  You just need to run a feeder to each bus.  But with a ring bus, that isn't necessary.  You can run 1 feeder.

Don - Specializing in layout DC->DCC conversions

Modeling C&O transition era and steel industries There's Nothing Like Big Steam!

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Posted by gregc on Tuesday, April 10, 2018 3:15 PM

DigitalGriffin
 
SpaceMouse

 I think this answers a question I have but I'm not sure. Does additional feeders reduce voltage drop, or are you saying you run parallel bus lines?
 

In essence, yes.

to which question are you answering yes?

greg - Philadelphia & Reading / Reading

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Posted by riogrande5761 on Tuesday, April 10, 2018 4:36 PM

Let me throw a fly in the oinkment.  *snort*

If you use suitcase connectors to connect to the bus, I'd guess if it is stranded some of the wires will be severed.  You can get then to go from 18 to 14 AWG and house wire IIRC is 14 AWG and fairly economical for a bus.

Rio Grande.  The Action Road

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Posted by BigDaddy on Tuesday, April 10, 2018 6:26 PM

mbinsewi
If you use the "suite case" connectors, don't you need stranded on both ends?

The 3M page specifies stranded wire for some of their connectors that I think would encompass useful sized connectors for bus/feeders that we would use.  The knock off suitcase connectors don't usually specify.

 
 

Henry

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Posted by DigitalGriffin on Tuesday, April 10, 2018 9:50 PM

[quote="gregc"]

to which question are you answering yes?[/quote]

lol. Well I guess that would make a difference.  Adding more bus wire would help  (Second question.)

 

Don - Specializing in layout DC->DCC conversions

Modeling C&O transition era and steel industries There's Nothing Like Big Steam!

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Posted by SouthPenn on Tuesday, April 10, 2018 10:59 PM

I ran parallel #16 stranded wire to brass shorting bars. I ran a single #16 wire from the shorting bar to the #22 track feeders and connected them with wire nuts.

The shorting bars were installed about every 10' - 12' with parallel #16 wire running between them.

South Penn
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Posted by CMStPnP on Wednesday, April 11, 2018 9:14 PM

BTW, I just bought some "suitcase connectors",  I was not aware Fry's Electronics sold them but most Electronics stores I visited called them "T-Tap" connectors for the T-Connection type OR "In-Line connectors" for the single line conversion type where you shift from one wire gauge to another.     I just bought the 14 guage to 16 guage T-Tap connectors and will use either terminal blocks or solder for the feeder wires.

Model Railroader has a video on youtube somewhere where the guy recommends piano wire for feeder wires and then he takes a pliers and shapes them like track spikes and uses a real small drill to drill the hole through where a track spike would be on a RR tie.    I thought that was an interesting approach but he never said what size piano wire.    Is there only one size?   Beats me and how he solders such a small wire to the rail without melting the tie would be a neat trick unless he just drives it in like a spike......he didn't say in the video.

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Posted by BigDaddy on Wednesday, April 11, 2018 9:25 PM

CMStPnP
I thought that was an interesting approach but he never said what size piano wire. Is there only one size?

No there are lots of sizes.  22 ga wire is 0.025" in diameter.  I would think running it through the tie would make melting the tie even more likely.  Lot's of hobby shops sell it, in the K&S rack with the small brass and aluminum tubing and rods

 

Henry

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Posted by CMStPnP on Thursday, April 12, 2018 12:38 AM

BigDaddy
No there are lots of sizes.  22 ga wire is 0.025" in diameter.  I would think running it through the tie would make melting the tie even more likely.  Lot's of hobby shops sell it, in the K&S rack with the small brass and aluminum tubing and rods

He was using hand laid track so it could have been wooden ties in his case but still thats just too small for me to solder without burning everything up.   It also means bare exposed wires under the layout.    Myself I am going to try soldering under the rail near the joint to see how that works.   I think that would be a lot easier to hide.

Brass Tubing, h-h-h-m-m-m, think I'll try that as lining for my switch machine shafts.   My Dremel can cut those to custom sizes.

BTW, I just noticed Amazon sells T connectors as well and via PRIME, but looks like a lot more expensive than Frye's Electronics. 

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Posted by DigitalGriffin on Thursday, April 12, 2018 11:34 AM

CMStPnP

BTW, I just bought some "suitcase connectors",  I was not aware Fry's Electronics sold them but most Electronics stores I visited called them "T-Tap" connectors for the T-Connection type OR "In-Line connectors" for the single line conversion type where you shift from one wire gauge to another.     I just bought the 14 guage to 16 guage T-Tap connectors and will use either terminal blocks or solder for the feeder wires.

Model Railroader has a video on youtube somewhere where the guy recommends piano wire for feeder wires and then he takes a pliers and shapes them like track spikes and uses a real small drill to drill the hole through where a track spike would be on a RR tie.    I thought that was an interesting approach but he never said what size piano wire.    Is there only one size?   Beats me and how he solders such a small wire to the rail without melting the tie would be a neat trick unless he just drives it in like a spike......he didn't say in the video.

 



That's how I did mine for the longest time for appearances.  I soldered wire onto a rail spike and drove the spike in.  It makes the wire "non visible"  Problem is over time I discovered sometimes the spike would work loose a little, and then the contact was lost.  So a little solder couldn't hurt either.

 

Don - Specializing in layout DC->DCC conversions

Modeling C&O transition era and steel industries There's Nothing Like Big Steam!

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Posted by bearman on Thursday, April 12, 2018 11:49 AM

I do not use suitcase connectors, but if you do, from what I understand go with the 3M Scotchlok, do not buy any knockoff.

Bear "It's all about having fun."

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