DCC Allows 'simple' effective wiring
Experience with Zero-1 (+25years) showed it was beneficial to have 2 distributions: TRACK and ACCESSORIES
Modern Decoders, and Operational Accessories also require a 16V a.c. supply - so a 3rd distribution
Experience has shown the need to be able to ISOLATE during fault-finding (eg finding a short-circuit)
Therefore the layout includes the ability to switch-off the distributions to each geographical / logical area.
NOTE: These are NOT the same as the 'dc sections' used in an 'analogue-dc' (or ac) layout, but chosen for convenience in fault-finding.
(This may also involve withdrawing extendable rail sections from baseboard joins, and switchable (normally closed) track joins,
further subdividing areas during faulti-finding only.
Multiple Power Districts and Auto-Reversers are included. Indicators show Power-on-Track
2-Way plus centre-off (Isolate) power switches allow power supply changeover for testing/backup working
THIS DESIGN was based on 2 x 5Amp power sources (Main and Booster) EACH having inbuilt current protection etc.
By powering the track from one, and the accessory control from the other,
a live-frog point can be changed even when it has shorted the track with an overun.
To equalise the load, the layout was split 50:50 with 2 x 5 Amp supplies, but either supply could be selected to any independant
section by the centre-off- toggle DPDT switches, in the case of a failure or for testing.
Please Note: The original diagram below has been subject to modification since due to changes in the Power Sources and Electronic Section Protection (see later)
Note: Ability of Booster above to work briefly in parallel with main DCC source, as a loco bridges sections, is due to it including an Auto-Reverse
ability to match polarity. Voltages should also match throughout.
Not all boosters may include this. The later design uses smaller 2.5A-3.2A Roco Boosters, creating more full Power Districts.
The Electronic Breakers installed at the same time ONLY ISOLATE ONE SIDE and therefore due care needs to be taken in how they are installed, to ensure correct orientation/polarity!! (DPST versions ARE available by buying the 'Auto-Reverse' versions)
UPDATES
PS-X Intelligent Solid-State Circuit Breakers are being added to 'Barnstaple' and 'Storage' Areas, NCE EB-3 (18V limit quoted! -not 23V ) for the remainder
The PS-X claims an intelligent start-up which can cope with the surge current of sound locos powering up
Incline Reverse Loops shortened to 'Train Length' to minimise voltage drop differentials at ends, aiding detection, and Inclines Powered separately (for easier fault-finding)
Earlier experience with the Auto-Reversers on the Garden LGB showed that they needed a good dcc-track-supply to operate correctly.
PB-3 breaker removed in favour or more PS-X Intelligent breakers: PB3 found unsatisfactory in this installation.
(Initially 1 spare PSX has replaced the PB3 in the same position - but will be 3 on output side as existing Barnstaple and Storage Areas )
'A Major Strategy Change':
Changing from the ZTC511 (5A output) as Master, to the Roco Multimaus (2.5-3.2A output), required a change in Power District Sizes
due to the number of Locos fitted with Sound, and Coach Lighting.
This coincided with learning that Roco Amplifiers 10764 and Boosters shared the same circuit board (ie the innards were identical)
A Stack of Amplifiers from Digital Start Sets were therefore modified to be usable as Boosters (by adding a loop-through socket)
'The Great Unknown'
An unknown quantity at this time, and into the future, is the current demand of the Locomotives and Coaches: The number with Sound will only increase, adding to the demand,
and increasing the Start-up' surge current. This has already shown itself in the past with the smoothing capacitor of Hornby's illuminated Pullmans,
which prevented the (5Amp) ZTC511 from starting easily, and again recently when testing with a Single Roco (3A) Amplifier, a couple of sound locos and 3 bulb-illuminated coaches.
The bulbs will be replaced with LEDs as soon as possible! Hence the decision to monitor current continuously as in Zero-1 days!
The Power Districts have been redefined as below:
Note: EB3 replaced by PSX
Each Colour represents a Power District: Sub-Districts are normally linked but isolatable for fault-finding at XRemoveable
Note: EB3 replaced by PSX
Designed assuming that a ZTC (5A) Booster would be providing the 'B' inputs to both Track and Accessory DCC distributions - but currently a Roco 3A unit.
Resulting in the 'A' Side switches being supplied by multiple Roco Amplifier & Boosters, with the 'ZTC 5A/Roco 3A' Booster on the 'B' Side.
(Master) Amplifier: Supplies DCC Signal to ALL POINTS/Accessories for CONTROL (not Power), and 2 'Programming' Tracks (The 'Operational Core')
By connecting the MASTER to the Accessory/Point bus, it is unlikely to be shorted out resulting in total loss of dcc on all devices
(Amps and Boosters). There is a small risk with the 'Programming Tracks' which actually form part of the main layout.
Also now connected to Storage A, but not normally selected (a 'high risk'), since the B source is used to spread/split the current load) - protection being provided by a PSX AFTER the switch. (If an 'A' position IS selected (anywhere except Pgm Tracks), then the corresponding Acc/Points should be set to 'B' for control)
Connection by link cable to each Booster (loop through - maximum 4 Boosters)
Booster 1: (3A) Barnstaple Junction Track and Approaches including GWR Victoria Road, with PSX Intelligent Breaker. (3 subdivisions)
Booster 2: (3A) via EB3 PSX (3 separately protected outputs: Left/Centre/Right) to Town & Fremington, Wrafton & Ilfracombe, Instow & Torrington Tracks respectively (A Future Option: - should more current be needed is to give each its own 3A Booster - The EB3 reduces flexibility in this regard)
Booster 3: 'B' Bus option for Track or Accessory Control:
ZTC (5A) / Trial use of a Roco (3A) depending on current demand (monitored by Tony's Train RRampmeters)
As more Locos are fitted with Sound, and Coaches with Lighting, the current demand is expected to rise:
7 Through Storage Tracks x 2 trains each (minimum), 3 Terminal Tracks and upto 16 locos => 33 locos @ 1 Amp each!!!!!
Tony's Trains LED DCC Volt and Ammeter Displays are fitted to all 4 sources: 'Barnstaple EB3 Input (sum of Scenic Left, Centre and Right)
These replace the Previously Used single ZTC 511 Current Display (when used as a Master), and are valuable monitoring aids.
One of the earliest additions to my Zero-1 layout had been Moving Iron AC Ammeters,and will monitor the AC Accessory Power supply here.
Normal Quiescent Current should be known so as to spot the abnormal!
Additional Features - requiring power!
Station Lighting (mostly LED) for all scenic stations
Working Container Cranes: Heljan, (Brawa) and Faller - the older cranes to be modified for Magnetic Grab as with the Heljan Cranes.
Working Cranes: Trix Gantry, Roco Gantry and Roco Breakdown (Mobile) Crane. Static Airfix Dockyard Crane
Moving Cars: Matchbox Motorway System (late 60's) for Congested Barnstaple Traffic (it may not always move!) and Faller (Wrafton High Street)
Other Working Features: Faller Swimming Pool, Hornby Tippler, Brawa Cable Cars and Fleischmann turntables...
Installed and Operational: LEDs indicate Power Present ('Trackside'): GREEN for Track,
YELLOW for Accessories, BLUE for 50Hz 16V ac Power
Each switched section is now fed separately, with both tracks isolated at the breaks. Optional breaks for sub-sections Changes: 'SpareAC'=Barnstaple AC, 'SpareAcc'= Pgm2/Tourist, 'AccCentre' = Inclines,
An additional DC Power Bus (12V dc) has been added for various accessories using 15A Red+Black Figure 8 flex (no appliacation as yet)
Created in HTMLEdit Studio by Phil Spiegelhalter on 21st September 2006/ revised August 2007
