The "Questions-Answers" column in the December, 2011, CTT perpetuates the myth that it is necessary to have a transformer that powers accessories in phase with the track transformer. They do not need to have the same phase--nor the same voltage, frequency, nor waveform. In fact, there are some advantages to having an accessory transformer out of phase.
I recommend that transformer plugs that do need to be plugged in in a particular way be marked not just "in some way", but according to the National Electric Code convention of marking or "identifying" the grounded conductor. This is normally done by coloring the insulation white, using a screw plated with a white metal, molding a ridge into zip cord, or doing something distinctive to that conductor. So a dab of white paint on the side of the plug that should go into the grounded slot of the outlet would be appropriate. On a modern outlet, the grounded slot is the wider of the two, or the first one clockwise from the round equipment-ground hole.
Bob Nelson
Bob, Not arguing the point that accessory transformers don't need to be "phased" I've only been inside a few transformers but I,ve never found one to have a "Grounded Conductor"
Found even fewer with a "Polarized" plug (One blade is wider than the other)
Banks, Proud member of the OTTS TCA 12-67310
The grounded conductor is whichever conductor the plug connects to the grounded slot in the outlet. I am simply saying that, when the desired way of plugging the transformer's unpolarized plug into the outlet has been discovered, I recommend marking it in the standard way, by "identifying" which of its equal-sized blades has been plugged into the grounded outlet slot and therefore has taken on the role of the transformer's grounded conductor.
I use a cord from Home Depot which has a polarized plug on it so that all of my KWs are polarized the same way. This eliminates some confusion. I don't have any significant number of accessories yet, so I need to keep the transformers polarized the same way for running trains. I usually get the polarization correct on the second try (smile).
The Lionel post war transformers are isolation transformers so that the output is totally isolated from the power line.
BB
Of course, as you say, the outputs are isolated.
The point of marking the plugs is so that they can all be plugged in the same way, with respect to the phase of the transformers' outputs. If they all have plugs with two identical blades, as were used when postwar transformers were built, all that is needed is that they all be marked consistently so that they can all be plugged in consistently. But, if some are polarized, either by having a wide blade or by having an equipment-ground pin, there is merit in using a standard marking for the ones that are not polarized. That way, ten years from now, you will not have to remember which blade you marked, but only that you followed the standard.
That being said, as a separate matter, I have recommended that one ground the common of the transformers' outputs, not to the grounded conductor but to the equipment ground or some other reliable ground. This protects you against electrical shock in the same way that any grounded appliance does, by tripping your branch circuit breaker if the layout wiring or track should come into contact with a harmful voltage, as it would if the insulation between the primary and secondary circuits inside the transformer case failed.
Grounding one side is a bad idea for TMCC, that would kill the signal!
I disclaim any expertise in TMCC, or DCS for that matter, until the manufacturers tell us what it is.
lionelsoni I disclaim any expertise in TMCC, or DCS for that matter, until the manufacturers tell us what it is.
Both TMCC and DCS are proprietary, and are not open source (they don't play well with others). DCC used in DC model trains is open source, and therefore has many manufacturers, user created options, and generally lower costs.
I'm surprised no one in 3-rail AC has tried to start an open source digital system.
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