Dynamis Compatability

[Spacejammed]

Hi,

New to Dynamis and got to say i love it, however my layout is big and finding low power spots already. 

My Question is do i have to use Bachmann decoders or boosters with the Dynamis system or can I use another N.M.R.A. conforming product.

Thanks in advance.

[jward]

decoders should be standard. any brand should work on any dcc system. boosters i am not sure of.

if you are getting low voltage spots but not running alot of trains, you might not have enough feeders to the track. the rule of thumb i use is you should have one set for every 6 feet of track. also, if you have alot of locomotives sitting around not in use, it would help lessen the drain on your command station if you gap the sidings and wire them to on-off switches, like you would on a dc layout. decoders draw power whether they are running or sitting.

[Spacejammed]

Already ordered a ton of 24/2 wire from maplin and some resistors/capacitors for terminators, but the switch idea is new one to me thanks for the advice on that one.

[jward]

if you are going to use the on off switches, then you probably aren't going to want to run the typical dcc bus wire with feeders for those sidings. you'll want those switches placed where it will be convenient to operate them, and run your feeders for the sidings direct from the switch that controls each siding.

at any rate, i hope you are not planning to wire the entire layout with 24 guage wire. it's ok to run short distances from a bus line to the track, but for long distances you will need something alot bigger to avoid signal loss. i use 18 guage for everything. so far it's worked for me but alot of people claim even 18 is too small, and use 12-14 guage.

[captain1313]

Spacejammed,

Besides running more feeders you can also cut power consumption to the locos not being used by muting the sound on the Bachmann's by hitting F6 and turning the light off, with QSI's double tap F9 3 times to power loco down and double tap F6 to power up.  I have the Dynamis and have run 4 sound loco's at one time plus several more idling at the shop or sidings with no problem with power loss. 

Kevin

[Spacejammed]

i hope you are not planning to wire the entire layout with 24 guage wire. it's ok to run short distances from a bus line to the track, but for long distances you will need something alot bigger to avoid signal loss. i use 18 guage for everything. so far it's worked for me but alot of people claim even 18 is too small, and use 12-14 guage.

I confused 24/0.2 (24 strands) wire carries 6amps which should be good enough also will be twisting the wire and this will be for the BUS in Star formation.  What wire should i use for droppers.  I am using the following guide:

https://www.model-railways-live.co.uk/Features/Category/DCC_Controls_/Wiring_a_DCC_power_bus/

[jward]

i use 18 guage for everything. for the drops i wouldn't go larger then 18, or less than 22-24. if you are using the smaller sizes like 22 or 24, keep the drops as short as possible, under a foot is good.

like i said, i use 18 guage as a good compromise so that i don't have to keep different wire sizes and colours on hand. i also use different colours for each rail. it makes it easier to keep the wiring straight. mix up the two wires, and you have a dead short.

i also use the star topology in my wiring, and put my switches  at the center of the star. this is the way you'd wire a layout for dc, and i see some important advantages to keeping my wiring this way. the switches allow me to reduce power consumption by, say, turning off power to the turntable tracks. unlike using function 6 to turn off headlights, my way kills ALL power to the decoders on those tracks. it also allows you to quickly isolate any shorts on the layout by turning off power to that section.

for easy to use and wire switches, look at what atlas offers. the atlas connector is the one i am using.

[Spacejammed]

So I ok with the 24 strand for bus but go down to a 16-18 for the droppers?

[jward]

i'd go 18-24 for droppers. larger than 18 and you start getting wire as large as the rail. especially if you're using code 83 or code 70 rail. in the usa 24 guage is telephone wire, and can be bought in 2 to 4 conductor cables.

[Jim Banner]

Larger North American layouts that require long lengths of wire generally use 14 gauge (28/0.3) or even 12 gauge buses, up to about 30 feet.  Beyond that, additional booster are usually used to prevent the buses from resonating and producing large spikes.  Not too many are wired star pattern because of the all the extra wire required and because of all the gaps that are required to avoid loops.

The idea behind using short drop wires, generally less than 6", is to keep the buses close to the tracks above them.  Long drop wires, although able to carry the current, especially when there are multiple drops to the same blocks, start having problems with loops.  Consider what happens if you use 3 foot drops spaced 6 feet apart.  With the power bus spaced out from the track by the lengths of the drops, you could easily create large loops with 18 square feet of area each.  These loops can act both as resonators and transmitting/receiving antennae for the high frequency components of our rectangular wave DCC signals.  That is to say, these loops can lead to spiking at the leading and trailing edges of the DCC waveforms.  The larger the area of the loops, the more the problem is likely to show up.  Star topology does about the same thing except it can divide the railway up into triangular loops unless gaps are used, one pair per set of drop wires.  Twisting and bundling the wires can restrict the area of the loops but at the expense of using even more wiring.  Alternately, snubbers ("terminators") can be used but their ideal placement can be tricky to find in a star and is likely to change if the track plan is changed.

What is the big deal about spikes on the DCC waveform?  They can make it difficult for the decoders to correctly read the information contained in the DCC signals.  And if allowed to get big enough (over 30 volts or so) they can permanently damage decoders.  Neither of these increase the enjoyment of model railroading.

My personal preferences are somewhat different than those of the author you quoted.  I use Romex house wire for buses.  Romex typically consists of two 14 gauge insulated wires, one black, one white, plus a bare wire, all housed in a plastic sheath.  It is the cheapest source of 14 gauge wire and is insulated with a high grade nylon or cross linked insulation, and striping it out of its sheath is easy.  I like to twist the black and white wires around one another, about 3 turns per foot, to cut down on crosstalk (exchange of high frequency signals) between multiple buses.  This does not interfere with striping and soldering drop wires to the bus, exactly as shown in his photo https://www.model-railways-live.co.uk/userfiles/image/Image-4-v2.jpg .  Note the offset between drop wires - it is easier to off set them than insulate them.  While the author advocates Scotch Lock connectors, I still prefer to solder.

Lastly, the quarter test (North American dimes won't quite span the rails.)  Unless your layout can pass this test at every point along the tracks, you have not finished wiring it yet.  This is a Must Do test for all DCC layouts and one worth repeating any time you have mystery problem that occur at isolated spots.  Railways change over time, whether it is from you making changes or from mother nature being nasty, doesn't matter.  However, doing the quarter test on someone else's railway, especially during a show or operating session, is to be avoided at all cost if you wish to be invited back for a return visit.

Jim   

[jward]

i've done the quarter test on somebody's layout, in a tunnel. he was bragging about how smooth his new locomotive ran, and everytime i dropped the quarter on the rails it would stop. took him forever to figure it out. i've rarely had that much fun for a quarter.....

[Jim Banner]

i've done the quarter test on somebody's layout, in a tunnel. he was bragging about how smooth his new locomotive ran, and everytime i dropped the quarter on the rails it would stop. took him forever to figure it out. i've rarely had that much fun for a quarter.....

And were you ever invited back??

Jim

[Spacejammed]

Thanks all for your help bought some extra wire of lower gauge for the drops now see how i get on, I am hoping it will remove need for a booster.

[NarrowMinded]

Is everyone here on the same page regarding wire sizes
In the US 24ga. Wire is smaller in diameter then 14ga.

This may be very obvious to most but reading some of the above makes
me think there is some confusion base on the terms used.



NM-jeff

[Spacejammed]

see thats possibly where confusion is occuring as I in UK so are wiring gauges different i.e. in UK 24/0.2 has 24 strands and will carry upto 6 amps. but 16/0.2 will carry upto 3 amps and the other one commonly sold in UK for lights and point motors is 7/0.2 wicj will carry 1.4amps.