I am wanting to add a 0-5Amp AC current meter between my power supply and my DCC command station. Does anyone know where I can find some simple panel mount AC current meters for this application?
First; an AC current meter will NOT show the correct value. AC current meters assume that the waveform is sinusoidal, and provide the RMS value of that, which is the peak divided by the square root of 2 (1.41…). DCC signal is very close to a square wave, and the true RMS value is very close to the peak value.
Tony’s offers a meter that reads the DCC current correctly for a very reasonable price:
http://www.tonystrains.com/technews/rrampmeter_df-appnotes.htm
But I do want to read an AC current. I want the meter between the power supply and the command station and not between the command station and the layout. The power supply supples a true AC current.
Here is one:
http://www.allelectronics.com/cgi-bin/category.cgi?category=385&item=PMA-5A&type=store
and they have a 15A one for about the same price.
Hold it! The wave form out of the power supply may very well be a sine wave. The output from the DCC system to the track will not be a sine wave.
GO TO WWW.DEMARELECTRONICS.COM THEY HAVE A LIST OF DC AND AC PANEL METERS AT VERY REASONABLE PRICES ALONG WITH MANY OTHER ELECTRONIC COMPONENTS. THE METERS ARE BETWEEN SIX AND EIGHT DOLLARS, VERY GOOD PRICE COMPARED TO OTHER VENDORS
Hi guys, I find this thread interesting as I am in the process of rebuilding a new bigger and better RR empire and would like to do as many things “right” as I can. I’m somewhat familiar with the advantages of having an ammeter on your layout. If I understand it correctly, to reduce the chances of burning up your locomotive you put one of these thing on your layout. This would work fine and dandy on the old DC system when you normally ran one engine on one blocked section, but what about DCC? If you can MU several engines together as well as run other locomotives at the same time, and DCC does not require blocking like DC does, can this really be of any real advantage? If I understand DCC, all the engines parked on the track are still running (idling?) even if they are not being used. Would this not contribute to the draw on amperage? I understand that you could remove all the engines and run just one locomotive to monitor the amp draw on it under different conditions, but then you would have to remember all the conditions for all the engines (with my swiss cheese memory I’m lucky to find the train room).
Clearing up any my misunderstandings and conceptions would be greatly appreciated.
The current draw of locos when not running is very minimal. Blocking is used in DCC for two reasons, Block detection and circuit breakers. Block detection is used for signaling and other automation. Circuit breakers are nice when you have a loco short out on a turnout or during a derailment. It will only kill power to the district as opposed to having power cut to the whole layout.