Re: tsunami 2


Mark and Dale:
I have been using separate power systems for my NCE systems ever since I started.  In other words I have separate systems that control track power, for the 37 tortoise switch machines, and for accessories like LED's, sound, and action devices such as turn tables.  By doing this I eliminated stray signals or the chance to taking out everything at once.  I use two of the NCE boosters for the track and switch machines and an old MRC 2400 and 1100 transformers for LEDs and TT power.  Seems to work well and allows me to trouble shoot things easliy.

-----Original Message-----
From: Dale Buxton
Sent: May 17, 2021 7:51 AM
Subject: Re: [HOn3] tsunami 2


My Ramp/Meter is wired in as per the instructions and is working just fine. My start up current peak is about 0.23 milliamps. I do not get the 14+ volt reading at start up every time. Only occasionally. The SoundTraxx PDF for Sound Cars goes into this inrush current thing in great detail. So I have tried to obey the warnings in a like manner. I have only had this problem with Tsunami II decoders with Keep-Alive circuits attached. It might have something to do with consisting the sound cars with the locomotive and leaving them that way at system power off without freeing them from the consist prior to system shutdown. I just don't know. But every once in a while something confuses these decoders at startup and they don't work properly until they are cleared in some way. Either by removing power to them completely. Or clearing the previous consist record. Or re-selecting the locomove. or all of the above.  But, I have experienced exactly the same problem that Robert described. 

Tam Valley Depot has created a "Dumb Booster" to  separate the track power bus from the accessory's bus. As I understand the literature on the subject. Havinall all your accessory decoders on the track bus can also cause a current in-rush at system startup. It would seem as more and more items are added to the DCC world. More and more better ways to wire them need to be created.

Dale Buxton

On Mon, May 17, 2021 at 1:09 AM Mark Kasprowicz <mark@...> wrote:
I've not heard of this happening though perhaps putting the qjuestion to the Soundtraxx list might shed more light.

As for inrush that's a current thing, not voltage. I am not sure how your  RRAMP meter is connected Dale, but you do not mention the current reading because that's the one that shows the initial inrush on start up, the difference of 0.2 volts is insignificant. Inrush is created by a number of stay alive devices starting to charge their capacitors at the same time which tricks the system into thinking it's seeing a short because the demand is so high and so sudden. That said stay alive units have a simple circuit to slow the charge current going into them but which allows the stay alive to discharge fully when track power is not detected.

If you wire the RRAMP meter in series with the NCE output and not just across it, the inrush will be very apparent and much more than magnitudes of 0.2 in 14.

The stay alive is connected to the decoders' +ve and -ve DC rails. I think some of the early sound decoders seperated the motor circuit from the lights and sound but that no longer holds true.

Mark K

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