Feeder line isues
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mgj21932
I am wiring a new HO scale layout in DCC. I am planning to use a pair of Tam Valley Hex Juicers for AR polarity control of six reversing segments. The input to the hex juicer accepts 14 AWG wiring from the DCC track bus. Output is limited however to connection with 20 or 22 AWG wire.
I am aware of relationship between wire guage size and run length to voltage drop (and degredation of DCC signal). Locating two hex juicers more or less centered at opposing ends of the layout will minimize the lengths of the 22 AWG feeder lines from the juicers to the track segments. Still, at least some of the 22 AWG feeder lines could exceed 3-4 feet in length, and that is longer than the commonly recommended length for 22 AWG feeder lines. So my question is, can I alleviate the potential for excessive voltage loss by connecting the 22 AWG wire from the output of the hex juicer to a 14 AWG segment running to another connection to a 22 AWG feeder within a few inches of the connection to the track? First, is there any potential gain to be had from the larger guage wire between the AR device and the track feeder wire? Or is the short 22 AWG connection at the output of the AR device a controlling factore ("choke point"), such that there is no theoretical reduction in voltage loss to be gained by splicing a larger AWG segment into the feeder connection. Second, would the two added connections themselves provide sufficient additional resistence that would likely preclude any net reduction in voltage loss? I appreciate that, even if there could theoretically be a reduction in voltage loss from use of a larger AWG segment in the feeder line connection, there might be a trade off created by the additional connections. Under those circumstances, does anyone have an idea (or even just a guess) on how long the larger AWG segment would need to be in order to offset the detrimental effect of the two additional connections in order to yield a net reduction in voltage loss? Or would the additional connections present an insurmountable obstacle, either in terms of voltage loss or in degredation of the DCC signal. Any guidance, even purely theoretical, would be appreciated. Bill Demarest
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Don Vollrath
It is the overall in series resistance of the current path that limits the peak flow of current necessary to operate the AR unit. Twisted then soldered Wire to wire connections will provide a minimum of overall resistance to the intended current path. So make your own wire size transition using a short piece of 20/22 Awg soldered to the longer length of 14awg feeder wire at each end. Good alternatives include a solid barrel crimp splice.
DonV
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mgj21932
Thanks for the advice DonV. Will be sure to make good solid connections.
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BillD
On Jan 24, 2020, at 5:58 AM, Don Vollrath <donevol43@hotmail.com> wrote:
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Max Maginness
Why not use the dual juicers. One per reversing section.
Max
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mgj21932
Thought about that Max but 2 Hex juicers were much cheaper than six dual juicers. So bought Hex juicers to save a few bucks. Did not realize limit on size of output wires until the Hex juicers arrived and I could physically inspect them. Live and learn.
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BillD
On Jan 24, 2020, at 8:37 AM, Max Maginness <m.maginness@...> wrote:
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Max Maginness
The Hex juicers were really intended for turnout frogs in a dense area like a yard throat. The dual ones are much more suited for scattered reversing loops. (and of course the single ones for isolated turnout frogs)
BTW are all your reversing sections in the same power district? If not the hex scheme won’t work.
To late to do an exchange?
From: w4dccqa@groups.io <w4dccqa@groups.io> On Behalf Of mgj21932 via Groups.Io
Sent: Friday, January 24, 2020 5:43 AM To: w4dccqa@groups.io Subject: Re: [w4dccqa] Feeder line isues
Thought about that Max but 2 Hex juicers were much cheaper than six dual juicers. So bought Hex juicers to save a few bucks. Did not realize limit on size of output wires until the Hex juicers arrived and I could physically inspect them. Live and learn. BillD
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mgj21932
Yes. All in single power district.
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Planning to address the concern about voltage loss on 3’-4’ feeders by spicing in 14 AWG wire for most of the length. Do you have an opinion on electric conductivity efficiency of soldered vs physical butt connections?
On Jan 25, 2020, at 8:54 AM, Max Maginness <m.maginness@...> wrote:
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