Author Topic: The Stephenson Rocket  (Read 6562 times)

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Chris333

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Re: The Stephenson Rocket
« Reply #45 on: October 07, 2021, 04:56:37 PM »
0
In Japan they love little tiny round circle layouts. The caps let you run at very low speeds without worry about the dirty track. This is the guy I first bought them from, but have since found them elsewhere:
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I used them in my Nn3 boxcabs and they run off a 1.5 volt battery with no speed control at all, just on/off. But they work with a regular power pack as well just don't go over 5.5 volts.

mmagliaro

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Re: The Stephenson Rocket
« Reply #46 on: October 07, 2021, 06:31:47 PM »
+1
That's tremendous, Chris.
Believe me, I have considered using those caps many times, especially since I only run DC and almost never run a second loco on the track.  Years ago (I'm talking the 1990s), I bought a few and experimented with them.  But they have come a long way since then.

In a larger engine, where you could string 3 of those caps together in series to get about a 16v limit, (but 1/3 of the capacitance), I wonder if that would work.  There would be enough room in, say, a Kato Mikado tender for 3 of those... I think.
But I am not sure that these super caps really behave completely like capacitors in a series arrangement.
--
But again, unfortunately, I cannot use them in the Rocket.  There just isn't enough room.

Chris333

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Re: The Stephenson Rocket
« Reply #47 on: October 07, 2021, 06:37:58 PM »
+1
Another idea to throw out. This chassis has 6mm wheels and 12mm WB:
https://tomamw.miiduu.com/6171-nhoe009-dia60wb16mm-super-slow-drinve-unit-oso-power-0616-rtr

Still probably too big to fit in the tender.

peteski

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Re: The Stephenson Rocket
« Reply #48 on: October 07, 2021, 07:02:10 PM »
+1
In a larger engine, where you could string 3 of those caps together in series to get about a 16v limit, (but 1/3 of the capacitance), I wonder if that would work.  There would be enough room in, say, a Kato Mikado tender for 3 of those... I think.
But I am not sure that these super caps really behave completely like capacitors in a series arrangement.


LOL!  Max, what you are describing is a typical keep-alive module used in DCC decoders to allow locos to run through dead spots.


This is one of the TCS modules I reverse-engineered.  Where I'm indicating a single cap (Cx), it is actually a bank of 5 series connected 1F 2.7V caps.  Since these are capacitors, connecting them in series works just as you would expect.  In this case 5 series-connected caps result in 0.2F (220,000uF) capacitance and a max voltage of 13.5V.  The rest of the circuitry limits charging current, while allowing full current to be supplied when track power is lost. The Zener (along with the resistor) protects the caps from excessive voltage.

But the DCC keep-alive modules are connected to a rectified voltage in the decoder.  The polarity will never change.  And even thought reverse bias seems to work for Chris (and you mention that it is not as bad as doing it to electrolytic or tantalum caps), my former electronic training prevents me from ever connecting any polarized cap in reverse.  I just cringe!  :scared:
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mmagliaro

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Re: The Stephenson Rocket
« Reply #49 on: October 07, 2021, 08:49:44 PM »
+1
Pete, do you use "super caps" for those keep-alives, or are they just conventional electrolytics?
I presume they are the "super", because I don't think anybody makes such a thing as a 1F electrolytic capacitor
that isn't the size of a small dog.

peteski

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Re: The Stephenson Rocket
« Reply #50 on: October 07, 2021, 11:12:58 PM »
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Pete, do you use "super caps" for those keep-alives, or are they just conventional electrolytics?
I presume they are the "super", because I don't think anybody makes such a thing as a 1F electrolytic capacitor
that isn't the size of a small dog.

Exactly.  Maybe even a medium size dog!  Those are all SuperCaps.
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Chris333

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Re: The Stephenson Rocket
« Reply #51 on: October 07, 2021, 11:37:14 PM »
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Whatever I'm using is basically a battery is what I was told.

peteski

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Re: The Stephenson Rocket
« Reply #52 on: October 08, 2021, 03:14:03 AM »
+2
Whatever I'm using is basically a battery is what I was told.

Well, someone does not understand the difference between a battery and a capacitor (regular or super type).  Batteries use chemical reaction to "hold" the charge. Capacitors are simply 2 plates very close together that hold static charge due to laws of physics. There is no chemical reaction taking place.

But for a laymen I can see how the 2 different ways of storing electrical energy can be easily confused.  They are both "black boxes" with 2 leads that can hold electric charge. But what's inside the black boxes is quite different.

If you feel like reading, here is some educational info: https://www.explainthatstuff.com/how-supercapacitors-work.html

It all boils down to "But the big advantage of a supercapacitor is that it can store and release energy almost instantly—much more quickly than a battery. That's because a supercapacitor works by building up static electric charges on solids, while a battery relies on charges being produced slowly through chemical reactions, "
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randgust

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Re: The Stephenson Rocket
« Reply #53 on: October 08, 2021, 02:32:41 PM »
+1
There's some pretty cool applications out there.   The streetcar that our firm designed for Savannah, GA was a small commercial generator (marine type) linked to an entire bank of super capacitors in the floor.  All braking of the streetcar (stop-start-stop-start) was through the motor, so the braking energy could be recaptured rather than waste heat.   Very successful.  We had two gensets on board and found that it actually did just fine on one.  While there were other issues, the basic use of capacitors instead of a battery worked extremely well, allowing the use of a quiet biodiesel-fueled boat generator to top off the capacitors on demand.  And the Allen-Bradley controller system was stock - mostly to just keep the thing from spinning out on starting because the power dump to the traction motors could be .... instant.

Back to 1:160; I don't know what Jim Hinds (Richmond Controls) uses for capacitors on his lighting boards, but they charge and hold for an impressive period to just light some LED's.   I've also used orange-juice can sized ones for a switch machine power supply for decades, you DEFINITELY want to discharge those before working on the switch machine wiring.   They are blasting up to eight big solenoids in my diode matrix switch controls by route.   

Capacitors good.... in the right applications.

Spades

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Re: The Stephenson Rocket
« Reply #54 on: October 08, 2021, 06:09:58 PM »
0


But for a laymen I can see how the 2 different ways of storing electrical energy can be easily confused.  They are both "black boxes" with 2 leads that can hold electric charge. But what's inside the black boxes is quite different.


Electricity, a science to the left of witchcraft


If you feel like reading, here is some educational info: https://www.explainthatstuff.com/how-supercapacitors-work.html

It all boils down to "But the big advantage of a supercapacitor is that it can store and release energy almost instantly—much more quickly than a battery. That's because a supercapacitor works by building up static electric charges on solids, while a battery relies on charges being produced slowly through chemical reactions, "

I can finally grasp how an emergency excite switch works.

mmagliaro

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Re: The Stephenson Rocket
« Reply #55 on: October 10, 2021, 06:06:34 PM »
+18
Here's the next construction update.
Wheel revisions, wheel mounts, driver plating with nickel, wheel pickups, and the early stages of how I think the drive is actually going to work.  At present, the tender weighs a "whopping" 7g, and the engine about the same.  There will be some more gains, but I don't think they are each going to be more than about 10g.  Unknown whether I can really make this work, but anyway, here we go!



























« Last Edit: October 10, 2021, 06:13:47 PM by mmagliaro »

nickelplate759

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Re: The Stephenson Rocket
« Reply #56 on: October 10, 2021, 06:15:22 PM »
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Oh...My...God!

That's amazing (already)!
George
NKPH&TS #3628

I'm sorry Dave, I'm afraid I can't do that.

Angus Shops

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Re: The Stephenson Rocket
« Reply #57 on: October 10, 2021, 06:37:16 PM »
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Oh...My...God!

That's amazing (already)!

This. Exactly this.

peteski

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Re: The Stephenson Rocket
« Reply #58 on: October 10, 2021, 08:20:29 PM »
+2
And we thought that Max's last scratch-built N scale loco was the shiz, and here he is outdoing himself again.  I don't know what to say.  :)  Is there such a title as NMRA Grandmaster Model Railroader?  If there isn't, they should consider it.
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Chris333

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Re: The Stephenson Rocket
« Reply #59 on: October 10, 2021, 09:16:25 PM »
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I have hope that it won't be a rocket with that gear ratio. Just wonder if it'll be so light it just sort of vibrates instead of moving.