Chris, Thanks that's a cool site. I understand how the cap works, I just wondered if it would have the same effect with DC. Guess I'm old fashioned and living in the stone age with DC, but I'd rather have more weight than electronics in my locomotives. I even go further and remove all lights from them since in the 1950's locomotives would not have their lights on in the daytime.
Gadget Tom's is fast shipping for sure. Mine only took 2 days. The Supercap is made with a technology called Aerogel Foam (Carbon Nanotubes), but it is applied on a dielectric like normal caps, so it's really the same as an electrolytic cap in construction. Instead of just plates between the dielectric, they somehow build the carbon nanotubes on the dielectric. The carbon nanotubes hold a much higher electron density than regulat foil plates, so much more power is stored in these caps. I have only seen supercaps shaped like normal electrolytics, button sell chaped, and a square (CB Crystal Size) shape. I don't think they can be reformed like a foam, with the Aerogel Foam being the technology to grow the carbon nanotubes, not meaning they are formable like putty. As far as using them for DC trains, probably not possible unless you add a wireless radio digital control circuit for controlling them. In the most basic form of using caps for DCC, what happens is the decoder has a bridge rectifier to convert the track power into DC power. DCC track power is more than twice the full blast DC power, and changes direction at a high frequency. Opposite the track side of the bridge is where you install the cap circuit. The cap slowly charges to full capacity, then when track power is inturrupted, it bleeds it back off for the decoder to use. For DC use, the cap might not charge because the only power going to the loco is just what the motor needs to run at the speed you set. Maybe 2-4 volts. When the cap does charge, there is nothing to stop it from dumping it's full charge instantly. With a POP through your motor! I don't know how you could implement using a cap on regular DC locos.
Robert thanks, guess it will remain another DCC feature. I asked about reshaping because I have seen where people open the cap up and un-roll the foil to make mounting space paper thin. I think it was an EOT device in a HO scale flatcar in MR many years back. Oh well, it was worth asking ; )
Chris; I suppose i'm sure about the current numbers, i could be a decimal point off and be .1 and .2 amps respectively. To take the measurment, i followed the info on the meters for DCC page that you posted earlier. I used a 6amp bribge rectifier as the artical said. I temp-wred it in with aligator clips between the negeative track power lead and my meter set on the 10amp setting. My meter has three amp settings, uA, mA and A. The reading i took was the same on all three, only the fine reading beyond two decimal point changes to more detail. So i suppose this is right. I know that my old cheep meter that i was using on my failed test would not work at all on this test, as i found it lacked sufficent amp capacity to do the job. The new meter i bought yesterday cost me about $100 buck, and is much better and has "true RMS". Tony B....
I measured one of my GP35's and got 30mA or .03 A off it at 8 volts, so your measurements are pretty close. It depends on the speed you are going, and how many cars you are pulling. Well, I'm off to day 2 of the train show! Have fun boys and girls... I will be playing with my trains today!
.02A (or 20mA) would make more sense :teeth: it is neither .02mA, nor is it .2A Tony :zip: still as long as it doesn't fry :shade: Chris
there is a space for both - look at my mods of GP35: bambuko's GP35 mods I am adding the decoder and tungsten alloy weights :teeth: Chris
Rob, having sorted out power to the tracks, I have turned my attention to the decoder (DCX74zD) As it was my first installation (in amongst all the other DCC firsts on my little railroad :shade I didn't want to just install in the loco, in case I had any problems - I wouldn't know than, whether it was the decoder, my crappy installation or me still learning my PowerCab. I decided to test it before installation. One can buy ready made: NCE decoder tester but I had few old LEDs, bulb for the load etc laying around, so I have built my own. And we have success on all fronts :teeth: everything works fine and I am already programming my new baby ... without even having it installed in the loco :thumbs_up: the only tiny bit of concern is that LED brightness is slightly different depending whether I am in forward or reverse - can't understand this? Chris
no, no it is not this :teeth: I have already tried reversing things etc I suppose there is a way of adjusting the brightness of every light in the decoder anyway, so should be no big deal... just was puzzling me thanks for trying anyway Chris
Chris: are you saying the Front and Rear LED's are not the same brightness? If so, the resistors and LED's themselves have tolerances. Common resistors are 10% but surface mounts are 1 or 2%. LED's however are a different story, especially surplus. If you are saying that say the Front output is always brighter than say the Rear, that can only be related to the decoder's Function output transistor saturation which easily should be no problem for the really low current of LEDs. Some decoders (e.g. Digitrax but not NCE) can set the brightness but I don't know if you can do it independently.
I have repeated the tests today and you are right - it must be tolerances in resistors and LEDs I have used. The results are the same reagrdless of swapping of white and yellow leads or swapping different decoders - must have been the excitment and late night working that prevented me from thinking clearly :angry: for DCX74zD there is something like: 118 Mask for dimming functions: Bits => 1= Lf, 2 = Lr, 4 = F1, 8 = F2, 16 =F3, 32 =F4, 64 =F5, 128 =F6 119 Dimmer brightness: 50 = c . 50% of full strength 100 = 100% /no dimming effect. thanks for your help Chris
well, it was bothering me and here is the answer (at least one of the films I've had in mind) - very impressive use of capacitors to cary the loco over the dirtiest track with ease : http://kimsartshop.com/media/MOV00366.MPG Chris
You can paint a little over the LED to dim the bright one. Or, try roughing it up to scatter more light.
thanks Jeff, I will experiment with different LEDs, resistors etc - the combination I have "inherited" from the original MTL pcb is too bright when used with decoder (at least for me - looks silly). Here btw, DCX74zD installed in my Geep: Chris
I ordered DCC yesterday!!!! I also bought a Lokpilot micro to place in my gg-1. The lokpilot even got a mars light/ditch light/gyro light funtion!! But i dont want to destroy my gg-1 ( i am specially worried about the diode lights) last time i played with a decoder i let the "holy smoke" out of it! So i know i need to isolate the engine, and ajust the power out do the lights. Have anyone done this? I would like some pic`s!?
do you have ohm/continuity tester and do you know how to use it? just make sure that there is no electrical connection between tracks and motor - motor should only!! be connected to to the orange/gray wires of the decoder. Have a look at this page (for example): decoder installation plenty of good and reliable info with pictures and explanations: Lights for DCC Chris
