Subject:
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Re: Lego train basics
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Newsgroups:
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lugnet.trains
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Date:
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Thu, 27 Jul 2000 15:02:21 GMT
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Viewed:
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1304 times
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Larry Pieniazek wrote:
> > > 2.My large(three unit) gas turbine locomotive has four(4)motors.Does anyone
> > > think this will overwork the single power pack?
> >
> > Nope.
>
> 4 motors and no lights just barely won't overwork a single pack. IMHO.
>
> I feel that 5 will. That has been my consistent experience. The power pack
> cuts out and needs to be left alone for a few minutes to an hour to reset
> itself. (which is a testimony to the good engineering of the electronics
> inside the speed controller)
Interesting that it takes that long to reset. When I was a kid, I had a
train powerpack which used some kind of overload cutoff which reset
fairly quickly. I think it was basically a bi-metal strip (which bends
when the temperature gets too high, breaking the connection). I never
observed what it would do if a dead short was left (any self reseting
device which doesn't have smarts buiilt into it should reset and then
trip again if the short is left, so if it resets quickly, it will flip
on and off, of course a smart device could basically use the overload
switch to change things so the output is now just in series with a
current detecting circuit, which will only allow the reset to occur once
the current is removed).
> And opinions differ but I am a huge non fan of running two controllers onto
> the same track. Tiny differences in output voltage mean one of them is doing
> most or all of the work. Again in my humble opinion, I am not an electronics
> engineer.
As a (rusty) electronics engineer, I can't actually think of anything
which would cause a real problem when using two controllers so long as
they are wired up correctly, but then I also don't know how the overload
circuitry works, so there could be a catch there.
Note that there are plenty of real life situations where multiple power
sources are coupled in parallel (of course using more than one train
motor is an example of coupling mechanical power sources). Our electric
distribution grid is one example (though I think the interconnection may
be a little more sophisticated than just tying the outputs of all the
electric plants together). As long as there is a non-zero resistance
between two power units (guaranteed by the fact that our world is not
the ideal world of freshman physics), there is a load to dissipate the
differences.
--
Frank Filz
-----------------------------
Work: mailto:ffilz@us.ibm.com (business only please)
Home: mailto:ffilz@mindspring.com
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Message is in Reply To:
 | | Re: Lego train basics
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| Some minor disagreements with J2: (...) drive) (...) entirely a (...) Yes, it does matter. If you only have one motor, put it under the heavier end of the locomotive. Weight helps adhesion. It may be that the ends are close, but if you have a low (...) (24 years ago, 27-Jul-00, to lugnet.trains)
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