Brake on DC

[mbendebba]

Hello Folks:
Can anyone explain in plain english, or french, what the term break on DC means and why should I care.

Mohammed

 

[shropshire lad]

Re:Break on DC

Hi Mohammed
Basically when the loco decoder, with brake on DC set up, detects a DC supply it will stop. You can switch a shortish isolated section in front of a signal for example so the train will automatically stop when it is set to danger. Quite useful to avoid over running sidings out of your normal sight too. No use if you want to run a chipped loco on analogue tho because it won't run.

 

[Gizzy]

Re:Break on DC

Is that break, or brake on DC?

Pronounced the same, but 2 different spellings and meanings....

 

[Gizzy]

Re:Break on DC

I see Colin has the answer for you Mohammed....

 

[Neil Robinson]

Re:Break on DC

At the risk of thread hijack, I'm aware that some decoders, when used on an analogue system, will slow, pause and then accelerate in the reverse direction to before when the track supply is instantaneously reversed. The length of the pause and the rates of acceleration and deceleration are individually programmable.
I naively assume that all decoders with the brake on dc facility will do this.
I'd appreciate clarification of the above.

 

[mbendebba]

Re:Break on DC

hello colin:
it is brake I guess. It is spelled as Break on the Massoth website. In essence, a loco equipped with a brake on DC decoder will come to a stop when it encounter an electrical disruption in one of the rails. Is that it

 

[mbendebba]

Re:Break on DC

hijack away Neil, I want to know as much as I can about this, the more tangents the better

 

[mbendebba]

Re:Break on DC

I have locos equipped with first generation decoders and none of them ever failed to stop at a signal regardless of whether the layout was digital or analogue

 

[shropshire lad]

Re:Break on DC

The DCC bus is AC, if you interupt one side of the supply the loco will just stop. If you have an isolated section of track and switch that to DC a brake on DC loco will use the Dc supply to slow down and stop,run the sound etc until it detects that the DCC bus has been reinstated at which time it will move on again governed by it's programmed delay if any.
Neil
Totally unscientific but I've just run an anologue loco 'forwards' then reversed the polarity (by turning the loco round) and it ran 'backwards' with the same command. Seems the faux dc from the system is directional?

 

[mbendebba]

Re:Break on DC

Colin:
That is a perfect explanation. I get it, thank you very much
Mohammed

 

[ntpntpntp]

Re:Break on DC

I naively assume that all decoders with the brake on dc facility will [stop/pause/reverse with brake-on-DC]
I'd appreciate clarification of the above.

Pretty sure that's a specific Massoth/LGB "feature" to allow automation of a back-and-forth shuttle service without the need for external electronics, although I think some other decoders will try and "soften" the effect of quickly changing the DC polarity under analogue, which in some ways has the same effect as the feature you're describing. Very much depends on the decoder though.

Generally the "Brake-on-DC" function is as Colin described, ie. use it to slow a loco to a gentle stop in front of a red signal, and accelerate away again when DCC is re-instated to the rails. I've seen it used to great effect on an N gauge modular system, you just have to spend some time programing all locos to have reasonably similar deceleration characteristics so that they stop in the same distance. You can leave the acceleration rate different to suit the type of loco and train it's hauling.


Colin, yes indeed the "faux dc" on a DCC system is directional, otherwise you'd not be able to drive your analogue loco back and forth at will!

There are some decoders out there that are not great at running correctly under DC, which is why a lot of people turn off the "run on analogue" function in the decoder to avoid runaways if they're strictly a DCC only operator. I've got an older NCE decoder that sometimes seems unable to make it's mind up which way to run under DC, so that loco doesn't get taken to friend's lines! It runs perfectly on DCC.