Lenz Compact

[NZRMac]

I'm using a Lenz Compact (same as Atlas Commander) and Soundtraxx decoder. The Lenz puts 18volts on the track but the Soundtraxx has 16 volts max has anyone used this combo successfully or any suggestions

Ken[:p]

[cacole]

It sounds to me like the Lenz is putting too much voltage on the track. Most DCC systems put only 14 Volts on the track, and 18 volts could damage decoders and burn out lights. Check the documentation and see if the Lenz has a way to adjust the output voltage, and lower it to 14 Volts.

[rrinker]

I forget which of the many DCC sites this is on, but you can use pairs og high speed diodes to drop the voltage. You can also use an alternate input power supply with a lower voltage. 18 is definitely too much for HO, not only is it too much for the Soundtraxx decoders, but if you use low voltage light bulbs and use resistors appropriate for the normal HO voltage of 12-14, running them on 18 could allow too much voltage to the bulbs, shortenign their lives, or result in too much power being dissipated in the resistors, making them get hot. 18v is more appropriate for O and G scale.

[NZRMac]

I've had another look at the transformer I'm using and there is another tapping at around 11volts so makes the output of the controller about 15v at the tracks.
The controller still works ok, so when my decoder arrives in the mail!!!!!! waiting!!!!!!
aagggghhhhh!!!!!! hopefully all will be ok.

[bcammack]

There is a page on the Atlas site explaining how to drop the output voltage.

http://www.atlasrr.com/voltage.htm

[NZRMac]

Thanx I'll give it a try. I emailed Soundtraxx and they told me this

"Ken,

You should be fine with that command station. We have several customers using it with no problems at all.

Alan Lloyd,
Soundtraxx Customer Service
http://www.soundtraxx.com
210 Rock Point Drive
Durango, CO 81301
970-259-0690 (Ext. 14)
970-259-0691 (fax)"
So now I'm not sure, risk melting the decoder or reduce the voltage. Tony's Train Exchange has said use the diodes as well! I think that's the safe way.

[rrinker]

I would say that regardless of what Soundtraxx has OK'd, reduce the track voltage. 18v is too high for HO.

[Anonymous]

May I ask how you measured the voltage, with just a plain voltagemeter or did you use a scope, the first one is likely to give faulty measurements.

[Anonymous]

Coertsmit is right. Your voltmeter is designed to read sine wave AC voltages. The DCC signal on the track is NOT a sine wave so the voltmeter's usefulness is limited to detecting if the signal is present or not.

[NZRMac]

oh right it's just your average digital multimeter, so it might be wrong ?

[rrinker]

It's not going to read THAT far off. If it's a relatively high-end meter that reads True RMS, then it's dead on, actually. A more typical RMS meter is accurate for a sine wave but not square wave - however the difference is NOT huge. Certainly not so much that the reading of 18v is the equivalent of 12v RMS, or even 14v RMS.

If the meter doesn't do ANY RMS measurement, then it will read average volts, and for square wave signals, average = peak = rms.

[NZRMac]

I Tryed using the lower voltage tappings off the transformer but wasn't able to programme the decoder on the program track ( oh yeah the decoder arrived !!! yahoo!!!) so I've used the 15 v tappings and 8 diodes on the output of my Compact and have around 16 volts at the track. Makes everything work and the sound is louder!

Cheers Ken.[8D]