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Old 24-11-2017, 08:00 PM   #1
Nokonium
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Default DCC and DC switch

I have a friend who has some old DC locos and he’d like me to look at enabling, on my layout, for him to bring over his locos for some exercise.

Where is the think smilie when you want it?

If I wire up a ‘switch’ to switch power sources, override insulators in power sub-districts apart from ones on points etc. that would link the up line with the down line I think that it is possible. Anyone else done this? I have no intention of risking DDC locos on anything D.C.

Last edited by Nokonium; 24-11-2017 at 08:03 PM.
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Old 24-11-2017, 09:12 PM   #2
kevin141
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Yes is the simple answer but you can run DC locos on a DCC system if it just running them they are fine but do not park them up for long as the motors do not like being stood most digital fitted will run on DC most will but do not have a electronic track cleaner in use.
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Old 24-11-2017, 09:21 PM   #3
Steve M
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DCC loco on DC is fine. DC loco on DCC is a potentially expensive no-no.
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Old 24-11-2017, 09:22 PM   #4
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Am i mis understanding this. DCC locos run perfectly on DC, whereas, the opposite, DC,locos on DCC, is to be avoided, at all times. john
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Old 24-11-2017, 09:41 PM   #5
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No, you are not misunderstanding, it is not wise to run DC locos on DCC.........HB
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Old 24-11-2017, 11:07 PM   #6
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To run DCC on a DC layout one needs to make sure the decoder is set to accepted current, that there are no electronic track cleaners and that the DC controller is not a feedback type. Both feedback and electronic track cleaners will confuse the decoder into thinking it is reading a DCC signal.

To run DC locos on a DCC layout is possible (Was the main reason why I origionally bought into DCC as back then decoders were the same price as locos!) but not advisable.
While when DCC first came out some DC locos had been tested on DCC, and I'd been told some had been tried for a considerable number of hours without any issues (Back then most locos had Ringfield or pancake motors) but since those days, I've been informed that the mini vibrations (A DC loco on a DCC layout with a DCC controller that also runs a DC loco.... The loco has a buzzing sound when on the track due to the mini vibrations of packets of DCC info travelling through the rails) can with fragile motors damage the coating of the windings so one can end up with a short in the windings which is either new motor time or is new windings time.
I have run DC locos on my Lenz DCC system and had no issues but I've not ran them for long. More of a test for the loco and a few trips round an oval usually followed by a DCC loco for fun. The DC loco at address 0 acts like a DCC loco in that it runs and is controllable totally independent to the DCC equipped locos, and the DCC locos act as expected. I personally was fascinated how this was possible as how did the DCC locos receive current when the DC loco wasn't? Clever technology indeed!
Due to today's fragile motor windings, and the huge cost in today's locos and lack of spare motors at reasonable prices should the worst happen, it is not really worth the risk in damaged windings to run DC on a DCC layout? It is probably why newer DCC systems no longer have a DC capability like they used to, and this is a wize decision in general, as no one wants ones pride and joy to end up a static model.
So to sum up, while it is possible, it is generally best avoided, especially if you want your models to live long healthy lifespans.

Regarding a DCC to DC switch. This is a good idea. I presonally feel (Though I have had DCC for a while I've not yet had the opportunity to use it on a layout as yet) that I would wire it as DC and then connect my DCC control system to it. The reason why is I found a DC layout, especially if one has a larger layout, is so much easier when it comes to fault finding when it is in DC form, especially if trying to trace a short! The main difference in DCC "Mode", that the ideal situation is to have all sidings live regardless of the direction the points are switched in, so one could do with some switches to enable the DCC operation to be entirely live, and when in DC, it is not entirely live.
This is the ideal compromise... To have a main DC/DCC switch and several smaller DC/DCC switches.
REMEMBER. DO NOT LET DC AND DCC CONTROLLERS COME INTO CONTACT WITH EACH OTHER. I advize to use a double pole changeover switch as the main layout DC/DCC switch.

Last edited by Mountain Goat; 24-11-2017 at 11:31 PM.
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Old 25-11-2017, 12:26 AM   #7
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I wired my Dad's layout for DCC but with the ability to change the double track main line to DC if or when required.
Basically that meant 3 power districts: the outer main line, the inner main line and everywhere else.
The easiest way to switch it is to move everything off the two running lines into sidings and the depot, then the DCC controller is unplugged so the DC controller can be plugged in. It is limited as the full layout cannot be used but does avoid the need to remove everything from the layout.

I wouldn't risk having DCC and DC controllers attached at the same time unless the two tracks are completely separate.

From what it sounds like, you wouldn't need more than your running lines to be powered on DC either?

Last edited by Bazil; 25-11-2017 at 12:37 AM.
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Old 25-11-2017, 01:13 AM   #8
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I'd say most have separate DCC and DC lines. The main thing is to ensure that trains can't cross from one line to another.
Lenz used to sell a device where one could drive a train from a DCC area straight onto a DC area and back again. Not sure if other DCC manufacturers made them. I dont think Lenz still make such devices though, and I have no idea if they could only be used with the Lenz DCC system or with other DCC systems.
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Old 26-11-2017, 11:32 AM   #9
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So it is possible but I will have to keep it simple, two ovals and that is it.

DTDP switch for the power supplies.
Switches to reverse the isolation of DCC sections to form continuous ovals.
Isolators on both rails at crossovers.

As the point motors are digital, switching off the DCC power supply will essentially freeze them because there will be no commands to change them, so set them to straight on before switching the power.

Thanks everyone.
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Old 26-11-2017, 11:39 AM   #10
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One thing to note is are your point decoders powered from the track or from a separate bus.

If powered from the track source then applying DC to the same track could damage them so some further isolation advised.

Rob
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