Subject:
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Re: Even more Wow!! for your buck!!! was Re: Woo Hoo!!!!! (part deux...)
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Newsgroups:
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lugnet.org.ca.rtltoronto, lugnet.trains
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Date:
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Tue, 3 Jun 2003 02:23:44 GMT
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Viewed:
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245 times
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In lugnet.org.ca.rtltoronto, Larry Pieniazek wrote:
> In lugnet.org.ca.rtltoronto, Brian H. Nielsen wrote:
> > In lugnet.org.ca.rtltoronto, Larry Pieniazek wrote:
> > > In lugnet.org.ca.rtltoronto, Brian H. Nielsen wrote:
> > > > In lugnet.org.ca.rtltoronto, Larry Pieniazek wrote:
> > > > > In lugnet.org.ca.rtltoronto, David Koudys wrote:
> > > > >
> > > > > <snip>
> > > > >
> > > > > Regarding reverse loops and DCC I seem to recall that it's possible to
> > > > > automate them so you don't have to cut gaps that the motor has to coast
> > > > > across
> > > > >
> > > > > See this track diagram
> > > > >
> > > > > http://members.shaw.ca/sask.rail/dcc/loop.html
> > > >
> > > > I'm not up on DCC, but with normal track it is normally done by having the
> > > > loop divided into 2 power blocks,
> > >
> > > That diagram is divided into two blocks. One for the approaches, and one for the
> > > reverse loop itself. That's standard wiring, been done that way since I was a
> > > wee lad, there's no need to divide the reverse loop itself into two blocks.
> > >
> > > With conventional control (for example the old ATLAS line of components) you
> > > reverse the loop block to match which way the train enters and while the train
> > > is in the block, you reverse the approach block.
> >
> > Okay, yeah, my memory of what I too used to do years ago got cross-wired.
> >
> > Then I guess I don't understand the set-up that is causing his need for a gap
> > to be crossed. Is it a DCC related issue or simply him not reversing the
> > polarity of the approaches while in the loop?
>
>
> The latter I think... by having a truck long gap, the motor coasts across the
> gap but never shorts out from one wheel set to the other, once it hits the
> powered side again (even though the polarity is reversed) it just continues on.
>
> This is actually an elegant solution if you can handle having the trains lurch a
> bit. At the speeds we work at that's not a problem. For a two truck diesel in HO
> that has interconnected power pickups on the trucks, and which is operating at
> realistic speeds, it might not work well at all.
> >
> > Brian H. Nielsen
Yep--Larry hit it on the head--the isolated section is so there isn't one set of
wheels on one polarity, and the other set of wheels on the reverse polarity--
(see if this font is really courier ;) )
######################
Track
TTTTT
O O
#######################
Track with electric truck on it
TTTTT
O O
###### #################
Pol.AB Pol.BA
Track with small gap--two different track sections opposite polarity--wheels on
either side causes short
TTTTT
O O
###### ##### ###############
Pol.AB none Pol.BA
Truck crosses gap--no shorts, no electricity at all
If the engine is going fast enuf, as Larry mentioned, it'll cross the gap no
problem.
Though the other idea, as Larry pointed out earlier, which is to switch the
polarity whilst the truck is entirely on that section is a great one, it adds a
further complexity--i.e. switches and knowing when the truck is in that 'block'.
THe solution above runs without any tipe of intervention at hte cost of the
motor not getting any electricirty whilst on the insulated gap--for LEGO doesn't
seem to be much concern.
After testing for an hour this evening on the layout in my living room, I have
noticed that, unless you're moving exceedingly slow, there is no problem with
the insulated gap. What is a big headache, however, are the switches--the train
invariably ends up losing comunication across the switches at any speed.
Doesn't happen all the time, but half the time the engine just shudders thru the
switch--and only on the turn--the straight thru seems to be less of a problem.
I have wired it up such that both sides are 'live' at all times, no matter where
the switch is, but still the train shudders thru half the time.
Anyway, more playing :)
I'll let you know how it goes.
Dave K
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