I believe (but not totally sure) that all PS2/3 DCS engines will run on DC. Has anyone thought about the advantages or disadvantages of running our DCS layouts on DC? Would the DCS track signal quality be better? What about power distribution? Would inductive effects be reduced?

Original Post

A while back I ran some tests to optimize the most reliable and fastest way to upload & download DCS files from an engine. I found that DC power did make a slight improvement in both upload & download speeds.

A couple years ago I experienced very interesting situation at a show where the power went out. Obviously no power means no running trains right? Not really. I disconnected my AC power supplies and rigged up my Milwaukee 18v cordless batteries to keep the layout running. At the time these were the XC batteries which were about 5AH. The fully charged batteries easily ran my 4 trains for the two and half hours the power was out and still were at 50% juice when I switch the power back. At the time I wasn't sure how long or how well this would work, so I took some precautions to extend battery life like not running smoke and removing a few of the lighted cars to conserve power usage.

During the above situation I didn't notice if the trains communicated any better or worse, but I do know that I had a mix of PS2 and PS3 engines running that all worked well on DC power. Those batteries saved the day, and for two hours I had the most popular layout that still worked!

H1000

GHD posted:

Interesting! Just curious where you put the 18 volts into the system. I assume to the input side of the TIU . Is this correct?

Yep, That's correct. The TIU received power from the battery off of the Fixed input 1 and the second battery was wired to the Fixed input 2. I also did use a WIU which was easily powered from a portable cell phone charging bank with a USB A to MINI B cable.

One very dangerous thing that I did was not using any circuit protection. As this was quickly thrown together, I didn't have any fuse holders or breakers to install between my TIU and the Battery. Keep this in mind if you attempt this setup.

H1000

DC works well for loading chain and sound files, but I have never seriously considered it for track power. 

GHD posted:

Interesting! Just curious where you put the 18 volts into the system. I assume to the input side of the TIU . Is this correct?

The TIU variable channels do not pass DC, they're AC only.  Using DC through the TIU restricts you to two channels.  I believe you could use DC in passive mode using the variable channel, but I've never actually tried it.

gunrunnerjohn posted:

DC works well for loading chain and sound files, but I have never seriously considered it for track power. 

GHD posted:

Interesting! Just curious where you put the 18 volts into the system. I assume to the input side of the TIU . Is this correct?

The TIU variable channels do not pass DC, they're AC only.  Using DC through the TIU restricts you to two channels.  I believe you could use DC in passive mode using the variable channel, but I've never actually tried it.

I never really tinkered too much with DC power sources on the TIU to actually run trains. Does that apply if the Variable channels are set to fixed output?

H1000

Yes, DC and the variable channels are mutually exclusive.  Like I said, you "might" be able to use them in passive mode without the DC going through the channel, but I haven't tried it. I use DC through the fixed channel on my workbench to load sound/chain files.

There is also some issue using DC on the TIU if you use DC on the AUX power, I remember Barry talking about this.  I haven't run into it, but it's something to take note of.

The question of AC vs DC comes up quite often. There are a number of products (engines, control systems  and accessories) which specifically state should only be operated on AC and this requirement should be observed. My layout is flexible and can run variable AC, variable DC and fixed voltage TMCC. Over the years, my experience has shown that many AC products will work on DC and in many cases (for example: conventional running)  the results are somewhat better with DC. As a side note, successful conversion to battery power is dependent on proper system operation on DC.

 

 

Some AC products that WON'T run on DC are all your TMCC locomotives, most Legacy locomotives, etc.

Rigatoni Express Railroad posted:

If you changed variable channels to fixed, would DC then work or are variable channels configured differently electronically?

No, they only work with AC. 

I haven't seen any benefit running DC. I bought large Bridgewerks packs and converted my G scale years ago from a suggestion of better signal. They handle big consists with plenty of power in reserve. So I guess that's the big benefit.

 The signal was the same with AC or DC for me. I believe it's more about good clean power and a lot of it.

" on Sour mash and cheap wine " ??

Why go back to DCC when I have DCS!

Engineer-Joe posted:
Rigatoni Express Railroad posted:

If you changed variable channels to fixed, would DC then work or are variable channels configured differently electronically?

No, they only work with AC. 

I haven't seen any benefit running DC. I bought large Bridgewerks packs and converted my G scale years ago from a suggestion of better signal. They handle big consists with plenty of power in reserve. So I guess that's the big benefit.

 The signal was the same with AC or DC for me. I believe it's more about good clean power and a lot of it.

Just as a note, the foundation of my recommendations for Bridgewerks throttle DC Power supplies was in comparison to other DC power supplies and was directed towards G scale/One Gauge users as DC power is what users in that scale use.   G scale MTH DCS users can use AC but most have other mfg engines which require DC power, so it is best for them to get a DC throttle power supply.

Mark:  The short answer is, if you are using the best type throttle DC power supplies (Bridgwerks throttle) then your signal results will be basically the same as an AC power brick or Z4000.    If you try to use the inexpensive DC power supplies that don't use the heavy copper wound transformers inside(like the Bridgewerks has), then you will get lower DCS track signal performance and encounter more operational issues.   Note that just because a DC power supply has a large copper transformer, does not mean you will get the best results.  With DC power supplies your results can and will vary greatly.  

I have a write-up on my DCS Tips page that covers my thoughts, observations and recommendations on power supplies:  http://www.rayman4449.com/DCS_...Type_of_Power_Supply 

Raymond

Ray's Electric Trainworks (MTH Authorized Service Center)

www.rayman4449.com

Don't forget about our HO set-ups, they run on DC too.  I use the TIU fixed-in with DC, an thus DC out to my HO layout.  I gave up on trying to run my old conventional HO engines using DCS because the variable in and out must be AC.  A while back I had some OGR members brainstorm some ideas on how to change that AC output to DC, and be able to change the polarity for going forward or reverse.  However, technically, it was beyond me. 

If MTH is listening, having a variable DC output from the TIU would help us HO & G scalers, to mention a few. 

Varying the polarity would be tricky.  I suppose you could do it just like a classic E-Unit, every time the power is interrupted, change polarity.  A latching relay would probably do the trick.

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