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Comment On MTH Site About Track Voltage

Started by chuff_n_puff, December 18, 2007, 07:32:24 PM

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chuff_n_puff

I read the following article on MTH's site:
Like the DCC standards established by the NMRA, M.T.H. Electric Trains took significant measures to ensure that our first HO locomotive complied with other NMRA standards whenever possible. Since our K-4’s release, some reviewer and consumer comments have been published that criticize the K-4’s operational functionality with power supplies that meet the NMRA’s minimum standard of 12 volts maximum power output. Understandably, those comments point out that the K-4’s top speed is less than expected when operating the train (with 12 volts applied to the track. A more typical max voltage output commonly found in today’s DC power supplies is 16 VDC.
To start with, most of today's power supplies are DCC, not DC, and it reads in AC on a multimeter. I have been operating my 18 train layout on 14 vdcc. If I crank my booster up to 16 volts, to satisfy MTH's K-4, what will that extra 2 volts do to my other trains? I will have to admit that I have been having some volume and other problems with the MTH and the 16 volts straightened it out and increased the volume. I just don't want to over power my other units just to get MTH to behave!

kevin2083

I wouldn't think that 16 volts would be a problem- the EZ command system uses about 17v and there haven't been any problems for me.
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Len

Chuff,

Where are you getting this, "To start with, most of today's power supplies are DCC, not DC, and it reads in AC on a multimeter.", from??

That doesn't jibe with the monthly sale report for the LHS my repair shop is colocated with. It shows for every DCC system they sell, 6 to 8 DC power packs go out the door.

While there are a lot more DCC users than there used to be, they are by no means the majority of HO and N model railroaders.

Len
If at first you don't succeed, throw it in the spare parts box.

SteamGene

Chuff,
Too much voltage is probably dangerous only to your locomotives and perhaps to any cars with lights in them. 
Gene
Chief Brass Hat
Virginia Tidewater and Piedmont Railroad
"Only coal fired steam locomotives"

MWHTrainGuy

I'm somewhat new at this.  I'm running two trains DCC using E-Z Command.  At slow speed they frequently hang up (i.e., stop) and the E-Z Command resets.  Do I not have enough power?  I've checked all the links and they seem fine.  It does, however, seem to happen in the same three or four places all the time.  Any thoughts on what's going on or solutions?

SteamGene

Sounds like local dirt or a lack of power to the track right there. 
Gene
Chief Brass Hat
Virginia Tidewater and Piedmont Railroad
"Only coal fired steam locomotives"

kevin2083

If the EZ command resets, it's because there is a short somewhere in the system. One thing could be that a metal wheelset gets petween the diverging rails of a switch. It doesn't take much to reset the controler. Even an old loco with a worn out motor can overload the EZ command.
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Atlantic Central

#7
chuff,

Not sure why you posted this? Do you have a MTH K4? Do you run DCC?

If those answers are both yes, you have no problem. The MTH K4 will run on your DCC system with no problem. Some of the functions are not numbered the same as standard DCC, but it works. You need not change anything.

If you are using DC, the MTH K4 will only run at a medium speed, regardless of the no load voltage supplied by your power pack.

Unless you have a regulated power supply, the voltage under load will be noticably lower than the open circuit voltage. Many typical DC packs read 16 volts or more, until you sit a loco on the track, then it drops to 12-13 volts.

Dispite that little blurb from MTH, and regardless of what a few power packs might put out, the correct DC voltage for HO is 12 volts. Motors/circuit boards in locos should be designed to provide reasonable top speeds at that voltage, or at least something close to it. NOT 16 volts - that is O gauge or large scale voltage!

Example - I use 13.8 volt regulated power supplies with the Aristo Craft Train Engineer Throttle system to run my HO layout. Under a 1 amp load (four powered diesel units) the max voltage is about 13.5 volts and the locos are traveling at about 70 scale miles an hour - perfect!

The MTH K4 was designed first to operated on MTH's own special system, then DCC and lastly to maybe run on DC - and it is only maybe!

The MTH K4 does not perform as per NMRA specs for DC - period! Mike Wolf can write all the little disclaimer blurbs he wants, but he will never sell me his propiatatary control system junk.

And, the AC volts of a DCC system have nothing do do with the voltage the motor actually sees after it goes through the decoder. The decoder turns it into DC and than delivers 12-13 volts DC max to "normal" HO locomotives.

One final note - as pointed out by Len, don't believe for one minute that DCC has taken over. In fact, the number of existing experianced modelers who are converting to it seems to have leveled off now at no more than 30%-40%, and among total train sales its use is still probably less than 20%. True, many new modelers will go directly to DCC, but even at that it will not replace DC any time soon, if ever.

If you don't believe me, just look at the fact that most manufacturers still offer both DC and DCC dispite the fact that the DCC locos run on DC, and the fact that Broadway Limited retreated from the "all DCC, all sound" sound position by offering the Stealth and Blueline products. Proof that many people are not using DCC and are not willing to pay extra for locos with decoders they don't need. Especially since many of those locos do not run as good on DC with their dual mode decoders as they do without the decoders installed.

Sheldon