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Discussion starter · #21 ·
For turnout motor power, a DCC book I have shows the wires coming directly from the rail. But for large scale, is it best to take the power from the bus? Or does it make any diff? Ditto for Kadee magnets?
 
#22 ·
If you run power to the rails well, just connect the turnouts to the rails. Remember the turnouts usually only draw power when moving, some people have problems, I don't.

Kadee magnets are permanent magnets. Magnets don't need any external power.

Greg
 
Discussion starter · #23 ·
Thanks Greg, makes sense.
On the other thing, I'd thought they were electromagnets, so thanks for the correction. I seem to recall an operations pdf on the Kadee site, I'll have to look that up.
===Cliff
 
Discussion starter · #25 ·
That's probably what I was thinking of, because I had this specific picture in my memory that showed the wires coming off the magnet. I was into model railroading ~35 years ago, HO, so I'm often confused as I try to correlate things and get back into the game. Thanks again George,
===Cliff
 
#26 ·
Posted By Greg Elmassian on 28 Dec 2010 12:29 AM
Remember that I have SS track and SJ SS joiners.

Yes, I used NoAlox on several test joiners about 6 months or so ago (have to look up the date), will be testing soon to see if there is any improvement.

Greg That's the problem Greg - Stainless Steel over time even with stainless steel joiners creates this resistance here and there that on my layout became even an audible feature - a higher frequency hum and if you touch the connecting rail clamp it's hot like a soldering iron - been thre burnt my fingers on it. I am throwing step by step my stainless steel out for ProLine's NI rail. Do to the drastic conductivity difference (1:10) of stainless steel versus Brass rail, Stainless steel layout are much quicker prone to problems, that can not easly be maeasured with a Voltmeter, but are being felt by the loss of response to DCC commands, i.e. an engine operating by no longer be reachable by the handheld. So what is the cause? Simply speaking signal distortion, the rectangular wave transition becomes too rounded and the input chipset no longer see that bit coming by, but yet there is still enough power for the train to run.
 
#27 ·
Posted By CliffyJ on 29 Jan 2011 08:04 AM
For turnout motor power, a DCC book I have shows the wires coming directly from the rail. But for large scale, is it best to take the power from the bus? Or does it make any diff? Ditto for Kadee magnets?
We connect our ProDrive DCC (Switch drvie with build in DCC controller) directly to the track at the beginning of the switch. There are no problems associated with that. I find it necessary to run a separate bus parallel to the track.
 
#28 ·
I think Axel means "unnecessary" in his last sentence.

I have direct experience with Axel's DCC switch drives, they are very low current, both in stand by and during operation. Very convenient to use.

Regards, Greg
 
#29 ·
Axel: I can easily detect a poorly conducting joint, SS, brass, or other. I made a load that draws 8 amps, and I connect it to the rails. You can easily measure voltage drop on either side of a joint with a millivoltmeter.

Regards, Greg
 
#30 ·
Greg:

I can hear one
Image
Sound like a bunch of bees in the rail - bezzz, bezzz, buzz

But that was not the poin of my post. When I was at ZIMO they showed me on their Oscar (German short form for oscilloscope) the wave deformation caused by high resistance that leads to non understandable DCC signals, yet still measures high voltage even with your high load.
 
Discussion starter · #31 ·
Hello Axel, good to hear from you.

Just so you know, I'm still planning on your R3 & R7 switches and DCC ProDrives for my initial layout build next spring.

All this reminds me of a chapter I read this morning in a DCC book, regarding powered frogs. I didn't see on your site the cost of upgrading the switches for the (between-the-points) microswitch that changes frog polarity, though they are obviously designed for that upgrade. (Forgive me if I'm getting something wrong, I'm struggling to get it all). Could you mention that upgrade price, email me it, or direct me to the link that I've missed?

Thanks, and best regards,
===Cliff
 
#32 ·
Axel, if there is not high resistance, then you will not see voltage drop. If you don't have voltage drop, then you don't have resistance. Ohms law cannot be repealed!

The DCC signal degradation would be from something else like inductance or capacitance.

Regards, Greg
 
#33 ·
CliffyJ, the R7 has a reed switch and a magnet for powering the metal frog.

Only the R2 and R3 need something to power the frog, and nost likely will not be needed for larger engines with 3 axles or more.

Problems could occur at low speeds on 2 axle engines with traction tires. Myself I have the first trailing unit behind an engine with power pickups tied to the engine (I do this with all steam tenders and powered LGB tenders). I even found frr sleeve bearings wheel sets for the toytrain tender for extra power pickups on my toytrain porters.
 
#34 ·
From what Axel describes, the resistance is probably non-linear. Low at low current, high at high current. Greg, your 8 amp test would filter for that automatically.

Also, if one can HEAR a bad joint, then something is physically moving to produce an acoustic response.
 
#35 ·
The "singing" joints always have extra resistance, and only sing under load.

I would hear them sometimes, and tried to locate them by looking for voltage drop. That was very difficult with a light load. My 8 amp load found them all right away, making it very easy.

I'm not sure I agree at all with saying that SS has more problems than nickel. I'd need some more side by side experience. My experience is that ANY clamp can get dirt into it if it's not snug, and temperatures and expansion and contraction make things move, which can allow contaminants into rail joiners and clamps.

One thing for sure... for the small amount of metal involved in the joint itself, the type of metal there makes no difference in terms of the conductivity of the metal, it's all about oxidation, contamination, contact areas.

Yes, over a long distance, SS has more resistance than nickel, but nickel has more than brass which has more than aluminum. The voltage drop along solid rails seems to be insignificant as compared as the resistance in the joints between sections. Even my cleanest joints can exhibit .01 volt under 8 amps of current. That's more than the loss in the solid rail.

Sure, if you want to take it to an extreme, like power a layout from only one point and run hundreds of feet, the difference in rail material will show, but to make a reliable layout, you need multiple feeders, there's no "Academy Award" for running fewer feeders, ha ha!

Eventually ANY joiner can fail or go to high resistance. Why have a layout that has no "backup"?

Regards, Greg
 
#36 ·
Posted By Axel Tillmann on 30 Jan 2011 10:49 AM
Posted By Greg Elmassian on 28 Dec 2010 12:29 AM
Remember that I have SS track and SJ SS joiners.

Yes, I used NoAlox on several test joiners about 6 months or so ago (have to look up the date), will be testing soon to see if there is any improvement.

Greg That's the problem Greg - Stainless Steel over time even with stainless steel joiners creates this resistance here and there that on my layout became even an audible feature - a higher frequency hum and if you touch the connecting rail clamp it's hot like a soldering iron - been thre burnt my fingers on it. I am throwing step by step my stainless steel out for ProLine's NI rail. Do to the drastic conductivity difference (1:10) of stainless steel versus Brass rail, Stainless steel layout are much quicker prone to problems, that can not easly be maeasured with a Voltmeter, but are being felt by the loss of response to DCC commands, i.e. an engine operating by no longer be reachable by the handheld. So what is the cause? Simply speaking signal distortion, the rectangular wave transition becomes too rounded and the input chipset no longer see that bit coming by, but yet there is still enough power for the train to run.


Alex

I would be most interested in seeing a scope trace for the effect you mention

A decoder that passes the DCC tests shouls have no problems. We have tried to destroy the DCC signal and only through large capasitenance is there a potential problem.

I have a lot of stainless in the garden and have never encountered any problems that would cause the signal to go out of spec.

Stan
 
#37 ·
Ditto Stan. I also have a scope, and better than that, I have a DCC packet analyzer that shows timing errors, etc.

There is no way for a DCC signal to stay a perfect square wave in the real world, but as Stan says, a decoder that passes DCC testing should be fine. I have all sectional track and there is a 100 foot section with 4 sets of drop in bridge clamps and still no DCC issues.

Regards, Greg
 
Discussion starter · #38 ·
Posted By Dan Pierce on 31 Jan 2011 06:12 AM
CliffyJ, the R7 has a reed switch and a magnet for powering the metal frog.

Only the R2 and R3 need something to power the frog, and nost likely will not be needed for larger engines with 3 axles or more.

Problems could occur at low speeds on 2 axle engines with traction tires. Myself I have the first trailing unit behind an engine with power pickups tied to the engine (I do this with all steam tenders and powered LGB tenders). I even found frr sleeve bearings wheel sets for the toytrain tender for extra power pickups on my toytrain porters. Thanks Dan, that's very helpful to know that the R7's have it and the R3's don't. Great tip. I'll be running one or two 2-axle loco's, so I'd better outfit accordingly.
Axel, any comments?
===Cliff
 
#39 ·
The R3 and R2 switches can be retrofitted with the same reed switch. The reed switch is disproportionally expensive for the price range in the R3 and R2 market. Putting the reed switch in by default makes the switch too expensive for the market. But the retrofit kit is easily installed.
 
#40 ·
Stan and Greg

There is a good old German saying that talk about "graue Theorie" (grey theory) which tries to state more along the line the proof is in the pudding or praxis is what counts. I don't' care about DCC approved or not approved. The reality is that chipset need a so called quick transition time from 0 to the trigger level of the input. If you slow the transition (as common when the rectangular signal is being rounded) then the input chips don't see the transition and miss that bit. Point in case the engine runs beyond the buzzing clamp but you can't control the engine at all anymore. Enough power to run but the signal looses bit information here and there. Once I clean out the buzzers it comes back to live. However, on the far distance of my layout I used to loose sometimes control as well until a put another feeder line in.

Once I replace the stainless steel with NI plated brass that effect will be gone, becasue at the core is brass therefore the slightly less conductivity doesn't play a role becasue we are still dealing with solid brass rail to conduct the electricity.
 
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