New DCC set 00501

[Michigan Mike]

Hello, my first contact. While waiting on hold to speak with a technician, I'll try to explain my question. After ditching all my Lionel O gauge trains and tracks, I've made the move to HO in Bachmann E Z Track. With starter set 00501, I have two trains running on a fairly simple layout which I hope to expand. I'm told by hobby shop that I will most likely need to run a bus line like I had with the O gauge layout. I used a voltmeter to detect weak stretches on the Lionel track and eventually all areas revealed about 18 volts on the layout. Mission accomplished. So now, in preparation for doing similar on the Bachmann E Z Track, I checked the simple oval with the voltmeter and I only detect about 1 volt of power. Is this normal? The trains seem to run fine, and I am using the power supply and controller that came with the set which I understand to be a 1 amp power supply. I realize I will probably need a 5 amp booster as my layout expands, but I don't understand why I only detect 1 volt of power on the track as it is now. Any suggestions? Thanks.

[Len]

DCC uses a constant 12 volts on the track in the form of a square wave, so most multimeters will not give an accurte reading. Especially if you have it set for DC. There are purpose built meters around specifically designed to show voltage and load current on DCC layouts.

Len

[rich1998]

My multimeters read about 13.6 VAC on my DCC layout. Multimeters will vary since it is not a pure AC waveform.

Rich

[Gary Allen]

Another problematic characteristic of the voltage waveform might be the frequency content.  I think it's pretty high and some meters might not be able to detect the True RMS voltage accurately at the higher frequencies.  My Fluke meter seems to work fine but it's a much better meter than those cheap ones you see at Lowes.  For sure, you must put your meter on AC.

[rich1998]

I use meters from Harbor Freight and I compared with my Scope which does peak to peak. Did the math and quite close. The Scope would show any spikes and there were not at the club layout. A meter will not show spikes.
I have a NCE Power Cab and the DC pack is 13.9 VDC. so I estimate the DCC is quite close.
Same at the club with the NCE Power pro. A club member has a similar meter and about the same voltage.

My meter with a added circuit makes a good five amp DCC amp meter.

Rich.

[rich1998]

All the OP has to do is put his meter on AC and put the probes on the controller output and take a reading and use that number as a benchmark. If the loco is running just fine, that number should be ok.
If he has an issue somewhere on the layout, with a loco there, probe and look for a lower voltage.
Some use a car light bulb as a load. You need a load to find a voltage drop.

Rich

[Gary Allen]

I think there are a couple of issues here: (1) Your meter is possibly inadequate to accurately measure the voltage frequencies associated with DCC.  I believe the fundamental frequency to be in the range 8 to 10 kHz with harmonics much higher.  I believe your old Lionel train provided power at the line frequency of 60 Hz.  (2) Measuring voltage drop along a track with no load is a waste of time.  There will be none (voltage drop that is).  About as useful as testing a battery with no load.

Assuming your meter is capable of measuring DCC voltage (even if not precisely), check if you are loading down your power supply (controller).  Do this by measuring the output of your supply (at the supply output), first with no load, then with both trains running at top (safe) speed with lights on.  If less than a 10% voltage drop, should be ok.  Now measure the voltage at the location of concern (along the track) with the both trains running at top (safe) speed, lights on, one passing through the location of concern.  If less than 10% drop from unloaded voltage, I would think you would be ok.  The simpler method would be to use empirical data, i.e. just see if the trains run ok.

I doubt there would ever be a significant voltage drop within the track rails, regardless of load.  The drop would occur at the rail-to-rail joints (electrical connections).