How Much Current Are You Drawing From Your DCC Booster?

[see DCC Accessories page]

If you are like most DCC users, you haven't got a clue. But you should. The current demands of an average DCC layout vary widely during operating sessions depending upon the number of locos in use, loco speed and load, and the number and type of other accessories that draw power from the DCC booster (eg loco lights, passenger car lights, integrated sound systems, etc.). How close are you to exceeding the capacity of your current DCC booster ? Are you contemplating dividing your layout into power districts and adding additional boosters when, in fact, your present layout has adequate reserves? Or, if you must divide your layout into separate power districts, what is the best way to do it to achieve a balanced DCC booster load?

You'll never know unless you can accurately measure the current your booster is putting out at any given point in time. Unfortunately, most DCC boosters manufactured today that have a capacity of less than 10 amps do not have a current meter built in or even a pair of terminals to connect to your own meter.

The problem is in the DCC signal itself. It is a complicated, high frequency AC signal that cannot be measured accurately with conventional AC ammeters. Extra circuitry is needed to smooth the signal into one that can be measured by inexpensive conventional meters without disturbing the DCC signal that goes to the tracks.

Another Tony's Train Exchange exclusive! We have manufactured just a device and are offering it for $15.00!

The CMC (Current Measuring Circuit) comes complete with a wiring diagram and can be installed on your layout in about 10 minutes. Order one today!

Informational note for CMCs using Digital Multimeters
I have the following setup using the CMCs with P30756 Digital Multimeters from Harbor Freight. Meters were chosen because of quality and low cost ($5-10) on sale. The setup is as follows:

Digitrax DCS100 and two boosters. CMCs used to read current for each booster section. One CVC connected to each booster connected to each meter. DC to DC converters used in the meters to get rid of the batteries and so meters could be mounted without further fussing with.

Now came the problem, I used a single “wallwart” to supply the power for the DC to DC converters to all three meters. Meters did not work and after discussions with Don Crano and hours of testing it became clear that some kind of feedback was at work. The solution and everything will work fine is to use a separate “wallwart” for each meter.

I am sure this problem would probably exist with all DCC systems but I
only own Digitrax so have not tested with other systems. Also note this situation would not happen with mechanical meters!

Jon Miller
AT&SF
For me time has stopped in 1941
Digitrax DCC owner, Chief system
NMRA Life member #2623

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