I have many years of experience with DC, but I'm now learning the DCC game. I've been running on our local club layout using DCC for about a year now. I have recently purchased a Digitrax "Empire Builder" set for my home layout. I have a question about 'power districts', or the subdivision of the layout into several sections so if one drops out due to some problem, the remainder of the layout can continue to operate.
My layout consists of seven sections (not modular), with electrical plug and socket PAIRS (28 total) between each section carrying the master power bus for throttles (4) and switch and accessory power. There is a minimum of nine wires in each interconnect. Each section of the layout has it's own control panel, with conventional 4-cab DC control (rotary switches), switch machine control, lighting control, etc.
I plan on using ONE of the existing four 'cab' positions as the new DCC 'cab'. Thus I can run either DCC or conventional DC on the layout, as desired. I do NOT plan on mixing DC and DCC on different parts of the layout at the SAME time (possible, but too likely to cause problems with complicated switching moves). We do this same thing on the club layout with no problems worth mentioning.
BUT, the whole club layout is just ONE big DCC power district. As we mostly run mainline trains for display purposes, this has not been much of a problem.
My home layout is almost all switching operation, where the possibility of momentary short circuits is MUCH higher (pushing against closed turnouts, minor derailments, etc.are almost normal occurances). Thus I wish to divide the layout into power districts so the whole thing doesn't go 'down' when somebody does something dumb, or just has bad luck.
IDEALLY, I'd like a high speed, sensitive, circuit breaker in EACH section. Digitrax makes such a unit, the PM42, but it has FOUR districts, and costs about $80 list. That's a LOT of money for seven sections, when I can only use ONE of the eight outputs on each unit.
Does anyone else make a similar SINGLE unit for less cost? Is a circuit schematic available for building such? I could probably design one, but why reinvent the wheel?
Will conventional non-electronic circuit breakers of suitable size trip fast enough to keep the Digitrax unit from shutting down (I suspect not).
Alternative ideas are welcome, but my existing wiring does NOT lend itself to a centralized multi-breaker unit like the PM42. That would require a whole new power bus for the whole layout, with attendant plug/socket sets (14), the complexity and cost of which would be nearly as bad as buying seven PM42's.
Dan Mitchell ============