Having now just installed an Alpha Meter in my layout power supply I find it raises a few questions that I thought would be interesting to share and get some thoughts and feed back on, hopefully as well, from the DCCconcepts chaps.

1) When I first turned the controller on I saw a current reading of around 0.6A.  This current fluctuates despite no locomotive being in use.  Do they draw any current when simply sat on the track?  No sound, not moving but just sat there.  My next step is to remove all locomotives from the track and see what the current reading is then!

2) When I operate locomotives the current continues to fluctuate, so difficult to judge the reading but I would say it rises slightly.  With five locomotives all running, with sound turned on, I reckon the current was anywhere between 0.7 and 0.9A.  I once saw it top 1.0A.  Is this a reasonable reading? If so I cannot help but wonder if a lot of controllers out there are way over sized for the layout they operate.  Signa Track used to do a 3A control unit and a 5A control unit but dropped the 3A unit.  The 5A was around £50.00 dearer but is now the only one you can get.

3) When the locomotives are running the current and voltage seem to vary by quite a bit and make reading the meter tricky.  My guess is that this is a result of dirty track, unless anyone has any other thoughts.

4) Finally the over current trip unit that I have wired in series before the meter now trips fairly frequently, it didn't previously.  I'm sure I've got it set at around 3 or 4A.  As this unit didn't used to trip I can only conclude that the trips are being caused by the Alpha Meter.  Can anyone suggest  what might be happening here?  The current on the meter is showing well below the current that should be tripping the unit and, of interest, the main Ecos controller is not tripping.
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Yes, anything that is across the rails will draw current, even when standing still. In fact the induction of the layout itself will create a tiny reading.

Current will fluctuate while trains run. A motor will, for example, draw more current as the train rounds a curve as the load is slightly higher.

Anything other than small changes is contact change. The meter is actually damped to minimise this but its still evident as we can only damp it so far without compromising accuracy.

I have not idea why your tripping device is reacting. We have one on every section of our large test layout and there is no issue. Perhas if your overload device is overjy sensitive move the meter the other side of it.

regards, Ahjay
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Thanks for your input Ahjay.  I actually removed all the locomotives last night and was still seeing around 0.35 to 0.4A.  Thereby proving that track and controllers themselves take some current as do locomotives sat there doing nothing.

Of course there are also three Cobalt SS controllers powered up as well but I wondered if the track itself would draw a little current.

The meter is certainly proving to be interesting already.
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After a couple of running sessions with the over current trip occasionally cutting the power I decided to remove it.  Interestingly the current reading now seems to be a little more stable as well so the interference would appear to be there even when the trip doesn't actually operate.  I think I will now simply rely on the Ecos to look after over current. 

What I really like about the Alpha Meter is that now I know what a normal operating current looks like which helps to set the over current limit at a realistic point.  Actually I'm quite happy with where I had it at 2.5A for now.
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