Converting kit built loco’s to DCC

[Tony ParkerParticipant]

I am in the throes of moving from analogue to DCC control. I have been told that I must insulate the motor from the chassis Being a bit dense I can’t think, of a way of isolating the gearbox has anyone any experience please. I hope to be able to get to Partington on the Sunday and speak to the guys there, but would like to get one of my GE loco’s running to prove that what I have done does actually work.

[Nick RidgwayParticipant]

Electrical isolation, yes. Because DCC comes through the track as alternating current with coding on it and the motor is direct current that has been decoded from the incoming power, so there needs to be a chip in the way to transmogrify what comes in into what the motor needs.

Mechanical isolation is impossible!

Why not go back to where it came from,  and ask that individual to explain further?

Do consider also isolating the signalling function from the driving function as part of the driving and operating design for the layout, otherwise DCC “becomes the message as well as the medium”, and real railways don’t work that way.

• This reply was modified 1 year, 9 months ago by Nick Ridgway.

[Tony ParkerParticipant]

Good morning Nick. Thanks for taking the time to reply to me. I think that the article I read was written by someone who was trying make DCC more mysterious than it really is. I appreciate the way DCC functions, the necessity for the decoder and so on. If I understand you correctly, what you are saying is that I must ensure that the motor contacts are properly isolated from the metal body and loco chassis which using Romford/Markits wheels is of course live to one side of the AC feed. A bit of insulating tape should take care of that. What I think that will have to do, is to mount the decoder in a totally insulated box either in the loco tender or in the case of my two GER M15 tanks in the bunker which isn’t that difficult as the leads of the 8 pin sockets and decoders I have bought are more than long enough to accommodate this.

[Paul WillisParticipant]

Tony,
There are two aspects of insulation that you need to think about:
– the gearbox (and motor, if integral rather than mounted on some form of drive shaft)
– the DCC chip itself.

You may not need to insulate the gearbox if you are using conventional pickups, and everything is fairly fimly fixed. However I have recently followed the 2FS route, and other 4mm modellers and started building split frame chassis to give improved pickup and reduce fiddling with bits of bent wire. With a floating gearbox as a result of CSB suspension, there was a risk that the gearbox could contact the insides of the frames, particularly on curves.

As a result, I found that the easiest way to insulate the gearbox was to position a Rizla cigarette paper against the gearbox side, and flood it with cyano to fix it. Once it had set, it was easily trimmed to size with a scalpel.

For the DCC chip itself, I insulate it with heat-shrink tube, rather than insulation tape. It’s cleaner and more convenient, IMHO. I had some previously, but picked up a lifetime’s supply from Maplin in their closure sale…

Unfortunately the EMGS Q&A doesn’t seem to allow the posting of images to show these. However I’ll post them onto the Scalefour Society Forum and provide the links here.

HTH,
Paul

[Paul WillisParticipant]

Image for insulating a gearbox from the frames:

https://www.scalefour.org/forum/viewtopic.php?f=90&t=2506&p=63181#p63181

Cheers
Paul

[Paul WillisParticipant]

And insulating a DCC chip using heat-shrink tube:

https://www.scalefour.org/forum/viewtopic.php?f=90&t=2506&p=63182#p63182

Cheers
Paul

[Tony ParkerParticipant]

Hello Paul. Sorry about the delay in acknowledging your response to my query in the EMGS forum. Presently, I use Romford/Markits RP25 driving wheels one side insulated, and the other live. Looking at you your posts on the Scalefour site, and thank you for that, I think the easiest way for me to proceed is to scrap or offer for sale the un-insulated wheels and replace them with insulated ones and fit two sets of pick ups. My interest lies in the ex-GE lines so I am dealing with small engines and I think that I will have to mount the decoders in the tenders of my J15’s, E4 or in the case of my F5’s J69’s in the bunkers in styrene cases. I have a number of engines running with Triang X04 motors which are bolted to the chassis. Insulating both sides will go so far to deal with shorts, but the problem will still remain of the bolt passing them the motor and inot the chassis. The answer I think will be to bore the mounting hole out and use a sleeve to isolate the motor from the chassis with insulating material under it.

Once again thank you for taking the time to respond.

Best wishes,
Tony

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