73490RE: Marklin CS2 and ESU Ecos
- Oct 30, 2013
In DCC there are two voltages to consider. the main one is the track voltage. IT can vary between 12vac and 15 vac depending on whose system you are using and the amps can be anywhere from 1 amp to 5 amps. It is here where the danger lies. a short at 12vac and 3 amps is 36 watts of power and that can melt plastic and burn decoders the best solution for reducing track voltage if your system can not be programmed for lower voltage is to use a bridge rectifier between system track voltage out an feed to track. Atlas Railroad company dcc site has good details using these, one bridge rectifier will reduce voltage to track by 3vac to 12vac and two will reduce it 6 vac to 9vac, but this does not address the amps . On some systems you can use a wall wart with lower specs to achieve this like on the NCE power cab which limits track power to 12vac and 1.5 amps. The second voltageto consider is the supply from the decoder to the motor in the engine. This is controlled by a CV in your decoder programming and set that to 10vdc max on some speed demons I even program this as low as 5vdc
Another way of controlling the amps in a short is to use a lamp or series of lamps in the feed to the track NCE has a variety of these in their catalogue. when a short occurs the lamp will light up and the filament will only draw the amps it was designed for so in a short 1 to 1.5 amps in the case of the NCE lamps so this gives you a visual clue that there is a problem and the lamp reacts faster than a circuit breaker. Even at 15 vac track voltage one amp to 1.5 amps will not melt plastic in the short term as it is only 18 watts max power there, where as at full 15vac and 3 amps track voltage you have 45 watts of power being dissipated in the short and that will melt plastic pretty quick.
---In firstname.lastname@example.org, <ralph.scott@...> wrote:Is anyone using either of these with dcc for their Z scale locos. I cannot find out what the minimum input and output voltages are? I currently use Lenz set90 @ 11v but I find it cumbersome to use. I was wondering if diodes can be used to drop the ouput voltage to 11v dcc .
I am now using Velmo decoders as these fit most Marklin locos
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