Subject:
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Re: lgauge.com update (DCC)
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Newsgroups:
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lugnet.trains
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Date:
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Sun, 10 Apr 2005 20:46:58 GMT
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Viewed:
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1286 times
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In lugnet.trains, James Powell wrote:
> > I had a look at DCC mods for Lego train motors, but people seem to have used
> > N-gauge DCC decoders so that they can fit the decoder inside the motor
> > casing. This may be good from a space saving point of view, but I'm not sure
> > about the power ratings of the decoders.
>
> James's current favorite: DZ 123. 1 Amp Continous, 2 Amp peak, 2 accessory
> outputs, series 3 decoder...
>
>
> > Lego trains are up to four times the size of N-gauge in each direction,
> > that's up to 64 times the weight, requiring 64 times the power to move them.
> > An N-gauge DCC unit won't be rated to 64 times a typical N-gauge load, so
> > surely Lego trains are overloading an N-gauge DCC module?
>
> Not at all. The lego motors are something like .3 Amp stalled, therefore they
> are conservatively allowing a 1 A decoder lots of room.
>
> I don't know what a 1A decoder would be like run at 1A for a long time, but
> under some conditions there can be problems with them. Above 35C or so, they
> tend to trip on overtemp after 1/2 hr or so.
>
> If you find it to be a problem, then I can see external mounting a DH decoder
> (probably if Digitrax, a DH123...which has the same rated current...)
>
>
> So, I'd just continue to use a N or Z scale 1A decoder inside the casing.
>
> James
>
> (I seem to remember the resistance of the motors to be around 33 Ohms...giving
> about 360 mA draw, but don't hold me to it!)
Some of my steam engines have 2 train motors, 2 technic gearmotors and 3 lights
in the firebox:
<http://www.brickshelf.com/cgi-bin/gallery.cgi?i=1149832>
<http://www.brickshelf.com/cgi-bin/gallery.cgi?i=1093549>
and the Pendolino has 4 train motors and uses the full 1 Amp continuously at
about 8 Volts (less than full speed):
<http://www.brickshelf.com/cgi-bin/gallery.cgi?i=707093>
Therefore it is likely that I would exceed the continuous rating of the decoder.
I like to run the motors at no more than 250mA continuous, preferably 200mA, so
I try to design the trains around this. All locos with enough room have
multiple train motors.
Considering that an N-gauge train is so small, have you ever heard of one
pulling 1 Amp continuously?
I understand that most DCC enthusiasts have one decoder per loco and then group
them together for multiple working. The Pendolino could have one decoder for
each powered vehicle, but they are at opposite ends of the train and therefore
under different loads as the train travels round the layout. I don't want the
back end pushing the middle off on a curve, so there must be an electrical link
along the length of the train.
I think the multiple motors (usually 2 per loco) would lead to an external
decoder being the preferred solution. An alternative would be one decoder per
motor, but this gets expensive when I have about 45 motors!
Do you find that with different locos naturally having different loads, due to
friction and weight, they run at different speeds with DCC as well as with
ordinary DC control? As an alternative to DCC, I was considering making a
closed loop PWM controller that would stop a loco racing down a hill and boost
its power up a hill, maintaining constant speed around a looped eight layout.
Mark
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Message has 2 Replies:
 | | Re: lgauge.com update (DCC)
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| (...) This "connection" can be digital, via the DCC controller. LDCC can't currently handle such situations automatically, but it can be done via software. There are also "speed stabilised" DCC decoders available, using various methods of load (...) (19 years ago, 11-Apr-05, to lugnet.trains)
| | | Re: lgauge.com update (DCC)
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| (...) (snip) (...) Yes, because the decoders are not limited to a N scale engine. If the 1A current is too limiting, the HO scale decoders are always a possibility for a external mounted decoder. (...) You do not require a electrical link along the (...) (19 years ago, 16-Apr-05, to lugnet.trains)
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Message is in Reply To:
| | Re: lgauge.com update (DCC)
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| (...) James's current favorite: DZ 123. 1 Amp Continous, 2 Amp peak, 2 accessory outputs, series 3 decoder... (...) Not at all. The lego motors are something like .3 Amp stalled, therefore they are conservatively allowing a 1 A decoder lots of room. (...) (19 years ago, 10-Apr-05, to lugnet.trains)
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