Re: Converting a DC Locomotive to DCC


Steve Haas
 

<<Carl,

Thanks, I am feeling better now.

Interestingly, I did place a piece of electrical tape on the frame and
rested the motor on the tape,effectively insulating the motor from the
frame. While I am waiting for the new decoder that I ordered to replace the
damaged one, I have not yet secured the motor to the frame with the screw.
As I mentioned in an earlier message, I will probably use a nylon screw just
to ease my mind.

Rich>>


Rich,

If I've been following this conversation correctly (that _is_ subject to
debate <GRIN>), in order to completely insulate the motor from the frame
you'll need to Both:

1) Put something (Kaplon tape(?) between the frame and the motor, and
2) use the nylon screw.

This is because both the motor to frame contact and the metal screw will
conduct current from the frame to the motor. Direct contact in one case,
and from frame>metal screw> motor case in the other.

Doing one without the other is most likely going to cause you problems.

Here's a link to the instructions for NCE's ATLS4 decoder, which is designed
for the Atlas S4, but can be used in similar switcher models:

http://www.ncedcc.com/images/stories/manuals/atls4.pdf


I forget which decoder you are installing (and which engine), but this
particular installation discusses many of the principals involved in
installing this type of decoder.

There are various sites (some manufacturers, some retailers, some just like
individual such as Bruce now that he's sold Litchfield, and various Yahoo
groups (Rick Bell's Yahoo DCC install group comes to mind) that have
installs in the form of clinics, Power Point presentations, etc. that will
show you tips and techniques on how to install various decoders into various
locomotives.

Best regards,


Steve Haas
Snoqualmie, WA














--- In WiringForDCC@yahoogroups.com, Carl <carl.blum@...> wrote:

Hello Rich:

Sorry, your statement is correct. I just wanted to point out the /just
/changing the screw to nylon doesn't assure insulation of two metal
pieces that the screw clamps.

As long as the decoder outputs don't have a current path back to the
power from the DCC rails, all should be fine.

Totally unrelated but interesting just the same, I designed a fixture to
set 25 digital clocks to the same time. I had 5 printed circuit boards
made to hold the clocks. I had insulated pads put in around the mounting
holes. Even with the insulators behind the circuit board it would short
out when I tightened the metal screws. I replaced the metal screws with
nylon and the problem went away. At this point I figured it wasn't
broken any longer, so I stopped trying to fix it.

Good luck, Carl.

On 3/12/2012 3:13 PM, Rich wrote:


Carl,

You just went and destroyed my fragile understanding of this entire
issue. LOL

I thought I understood that as long as the brushes were isolated from
the frame and as long as the frame was isolated from the rails, that
it was OK for the motor to touch the frame even if only where the
metal screw secures the motor to the frame.

Nuts, what am I missing?

Rich






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