DCC Controller, DC Transformer and Baseboard wiring

As well as using DCC control for the Locos I will need 16v ac for the Capacitor Discharge Unit (CDU) to fire the turnouts motors over and 12v dc for the Signals, Building and Street Lights and to drive a small hand held analogue DC controller for testing Locos that have not yet been chipped (converted to DCC operation).

To supply these additional voltages I am using an old H&M Powerpack, here is a front and back view;

Front View

This Powerpack supplies 16v ac from the left hand side banana connectors (yellow),
12v dc from the rear screw terminals.
12v dc from the right hand side banana connectors (from a separate winding of the transfomer so electrically separate from the rear 12v dc supply)



Rear View

I have made up a special cable to connect all three supplies to the layout via a 6 pin XLR female plug fixed to the black cable left, and a male XLR socket (fixed into the baseboard). This type of plug is used in the music industry for connecting microphones, speakers, amps etc and is extreemly robust.
 The black cable left has 3 pairs of wires as follows;
16v ac - two yellow banana plugs (right in photo) supply to the CDU
12v dc - red and black banana plugs (left in photo) supply for Building and Street lights, also supply for hand held DC Controller
12v dc - red and black spade terminals (centre left) supply for Signal control.


Here is a photo of the male XLR socket fitted to the underneath of the right hand baseboard;

The male XLR socket is to the right in the photo.
Also in the photo, to the left of the XLR socket is a male 2.5 X 5.5mm DC Chassis Socket.
I want to have all the power connections in one place on the baseboard, so this socket will take the plug from the NCE DCC Controller 6v dc PSU. Connected to this socket is some twin speaker cable which runs through this and the next baseboard to where the DCC controller pcb will be mounted. On the end of the speaker cable is a male 2.5 X 5.5mm plug which plugs into the DCC controller pcb.
The result of this is that I can have the DCC mains psu and H&M Powerpack co-located in a double mains socket, and connected to the baseboard with only two cables (one each).

The two 12v dc supplies, CDU output bus, DCC bus and 6v dc DCC controller supply run along under the baseboard using the coloured wires shown in these photos;

 

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The CDU is mounted under the baseboard to the left of the main power connector socketss, here is a photo;

It has a 16v ac input and provides a 20v dc output to crisp;y fire the turnout motor.











Finally, I have revised the wiring scheme for the layout as follows;

DCC Feed (balanced pair)

DCC Bus (32/0.2)

Black (outer rail)

Red (inner rail)

Drop Wires (16/0.2)

Black (outer rail)

Red (inner rail)

Turnout (t/o) motors Capacitor Discharge Unit (CDU) 

CDU Feed from transformer to CDU (32/0.2)

Black - 16v AC pair

CDU output Bus (32/0.2)

Green (t/o motor common 20v dc -ve)

Yellow (t/o operating switch common 20v dc +ve)

Drop Wires (16/0.2)

Blue - t/o operating switch to t/o motor left coil

Brown - t/o operating switch to t/o motor right coil

Standard DC to operate signals

12v dc Bus (32/0.2)

White (signal motor common 12v dc -ve)

Orange (Signal operating switch common 12v dc +ve)

Drop Wires (16/0.2)

Grey - signal operating switch to signal motor "on"

Violet - signal operating switch to signal motor "off"

Controlled DC feed for non chipped locos (using small H&M controller)

Feed from transformer to controller and output from controller to track via switch (32/0.2)

Green (+ve)

White (-ve)

Lighting feed (use same transformer output as Controlled DC feed above)

12v dc Lighting bus (32/0.2)

Blue (+ve)

Yellow (-ve)

Drop Wires (16/0.2)

Blue (+ve)

Yellow (-ve)

Turnout and Slip Frog to turnout motor change over switch

White (16/0.2)

Now I have the main supply and bus wiring done on this baseboard I can finally get down to laying some track, so this is what I will be doing next.

Layout wiring, including preparing Turnouts (Points) for installation

Since my last post I have been working out the track plan on the finished baseboards, this has taken a lot of thought and experimentation, but happy with it now, more on this in a later post.

So started to think about the wiring.
I am going to use a colour coded bus system to take the following feeds arpound the baseboards:

DCC Main Bus (balanced pair)
Black (outer rail) Red (inner rail)

Capacitor Discharge output to operate turnout (t/o) motors (20v dc +ve/-ve )
Green (t/o motor common) Yellow (t/o operating switch common)

Standard DC to operate signals (12v dc +ve/-ve)
White (signal motor common) Orange (signal operating switch common)

I will then take "drop" wires from the rails (Black/Red), t/o motors (Green), signal motors (White) and switches (Yellow/Orange) and connect them to the relevant "bus" wires using "Quick Splice" connectors, which alleviates the need to cut and solder any wires under the baseboard.

In addition the following coloured wires are also required;
Blue - t/o operating switch to t/o motor left coil
Brown - t/o operating switch to t/o motor right coil
Grey - signal operating switch to signal motor "on"
Violet - signal operating switch to signal motor "off"
These wires will go direct from the relevant switch to the t/o or signal motor.


The main bus wires are 32/0.2 stranded copper and the drop wires are 16/0.2 stranded copper.

Quick plug (get it?), I purchased all the wire and connectors on Ebay from "cm3models" who have provided an excellent service (no connection, just thought they deserved a mention).

In line with avoiding any soldering under the baseboards, I have come up with a way of pre-wiring turnouts and then installing them from above the baseboard.
This involves making a 1/8"cork underlay for the turnout with slots cut for the wires. This is glued to the turnout, the turnout motor is then fixed to the turnout through the cork, and then the wires are soldered on.
The turnout motors also have a single pole, single throw switch glued to them to change the polarity of the turnout frog, through the single wire factory soldered to the turnout frog.
Also, for DCC control, before the turnout is installed a couple of small bridging wires connecting the frog to the moving switch blades of the turnout have to be cut, to isolate the frog so that it can be powered from the switch glued to the motor (this is for PECO "live frog" turnouts).

Here is a photo of a turnout, turnout motor, turnout motor with switch installed and cork base.

And here is a photo of a completed turnout just waiting for the wires from the operating switch to be soldered on and then it will be installed on the baseboard, with the motor going through a pre-cut hole.

 

More details of track laying next time.