Ferrite Toroids and DCC (Was Bachmann Spectrum 4-6-0)


> Robby:
>
> The little doughnuts that you see are ferrite toroids. They add inductance
> to the wires and will reduce the level of high frequency pulses. This will
> also have the effect of causing a square wave to be rounded at the corners
> and the edges of the square wave will be more sloped than normal.
As one of Bachmann 4-6-0's just arrived and is down on my break-in
track, I was wondering if these ferrite toroids have a negative impact
for DCC as they "round" the square wave of DCC.
Chris
Reply to
Chris
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for DCC< We have a discussion on the LocoNet group about this (after I asked the question) and I believe the conclusion was they don't do anything to the DCC signal, so forget putting them on!
Reply to
Jon Miller
If both wires pass through the bead from the same direction then they have no effect on the DCC signals. On loconet we were talking about the Digitrax Loconet signals but track signals will work the same. If only one wire passes through the bead then rounding will occur. I suspect that the rounding will be very slight even in this case since the the beads with only one loop of wire really only present a significant resistance (impedance) in the > 30 Megaherz range.
Best,
Ken Harstine
Reply to
Ken Harstine
But they do help reduce parasitic oscillations that can cause radio frequency interferences.
Reply to
Rob Paisley
Chris:
At the frequencies that you are operating it will probably not be noticed. In fact, if there are spikes on the leading edges of the square waves it might make the square waves a little bit cleaner.
Allan Butler
Reply to
Allan Butler
The rounding of the signal happens only downline from the toroids. Thus, if they are on the motor leads, then the motor won't be seeing quite as sharp an edge to the power pulses. Considering the frequency of those pulses, the effect will be negligable to the motor. Upstream, the lack of a load on the sharp edges will make them even sharper on high impedance sourced edges due to the impedance kickback but with the values of the toroids, that will be only for very high frequencies and not really affect anything.
-- Bob May Losing weight is easy! If you ever want to lose weight, eat and drink less. Works evevery time it is tried!
Reply to
Bob May

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