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Hi Jerry-


As I progress with my reading of my LGB Telegrams I am now up to 1996 and in the Spring 1996, Vol. 7. No. 1 (page 39) Heinz Koopmann stated that the LGB Multi-Train System always carries 24 volts.



While Herr Koopmann's comments can be misconstrued to infer the MTS central station has a regulated output, in reality, this is not the case. If you supply 16VAC or 18VAC, the DCC track output will drop below 24V. When using a 20VAC transformer, I've also seen the track voltage above 25V.

It is hard to determine the context of Herr Koopmann's comments, but he may have been referring to the fact that DCC, unlike analog power, has a bi-polar signal on the rails at all times.

In any event, 24V is a fair assumption, especially if you are using a 6A/20VAC transfomer to supply the central station. Also note, 24V is overkill unless you need to run trains at high speeds.

Best regards,
Bob
 

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Jerry-
I've "Googled" the term "true RMS voltage" in the past and I've gotten good results.

http://www.kpsec.freeuk.com/acdc.htm

Remember, even if a meter is listed as a 'true RMS' meter, it may only be accurate within a given freqency range. The low end Fluke meters I checked online are only accurate within lower frequency ranges, e.g., frequencies between 50/60 Hertz, 45/500 Hertz, etc. The meter specifications are usually in your manual. To accurately read a DCC signal, you'll need a meter with a significantly higher frequency range.

Also note, some Fluke meters include a 'possible damage warning' if used at frequencies above 50/60 Hertz. Again, read your manual.

Good luck!

Best regards,
Bob

PS - You can always rectify the DCC waveform, filter it, and read the resulting DC voltage. Remember to add back the 0.7V drop for each resistor. You could probably build a small circuit board with "clip-on" leads for a few bucks.
 

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Jerry-


Hi Greg (and others),

Thanks for the explanation.



You are welcome.

As I mentioned in another thread, the RRampMeter IV is a very nice tool for the DCC enthusiast. The Tony's Train Exchange website is also a helpful tool for DCC beginners.

Best regards,
Bob
 
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