Hi all.

I seem to have discovered an odd problem with two 60215 CS2 causing a large voltage gradient (likely due to the isolation) and was wondering if anyone else had seen a similar problem?

My setups are as follows:

110V supply -> 110-220V step up transformer -> 100VA switching supply (marklins) -> 60215 CS2

The problem is that if you measure the potential between the center stud of the rail and the houses ground (or neutral), I'm seeing potentials anywhere in the range of 100-180VAC rms. If you're grounded, and you touch the center studs you feel a mild electric shock.

This happens at two completely different locations, with two completely different setups (i.e. a different step up transformer, 100VA supply and different 60215) so I don't think it's equipment/house wiring specific and rather the design, or the fact that I have a separate (isolating) step up transformer in the setup.

I did the same sort of test with a MS2 (also going through a step up transformer and it's own 18VA supply) and the potential there is only about 40V.

It's a 1:2 winding, so even at 120V supply we're still at 240V (my house voltage rings in closer to about 114VACrms). The output on the SMPS stage is also a rock solid 19VDC so the supply voltage really has nothing to do with this problem. Unfortunately there is no official 100VA 110(or 120V) supply available. The only thing I can think of is that the additional isolation stage in the step up transformer is allowing the output isolation of the 60215 to float high above. But any impedance path to ground should really cause it to pull back to zero thus eliminating the problem.

Hi Tulit,

I would also suggest you get a proper power supply for North American voltages.

As Ray points out depending on what the transformer looks like inside you may end up with various voltages between your house neutral and the output neutral of the transformer.

One could separate two cases:

1) Full transformer

This is a simplified drawing of a full transformer:



In this case there is a full isolation between primary and secondary sides and it doesn't matter which of the connection points to the left is connected to the house neutral and to the house phase wire. No need to use a polarized plug to connect this type of a transformer.

2) Transformer without galvanic isolation;



In this case there is electric connection between one of the poles of the primary side to one of the poles on the secondary side. For use in the US this type of transformer should (must?) have a polarized plug in order to connect the lower point in the drawing to house neutral and the upper to house phase.

It could be that you have a step up transformer of this type.



Finally, even if it is a bit off topic. My wife is from California. When we married (in 1985) she brought a few electrical items to Sweden. Most of them were replaced by 230 V versions and taken back to the US, but she had a calculator that she loved and on a business trip to the US I bought a 230 V to 115 V travel converter at Radio Shack. (A piece of crap, but a good starting point for doing my own design and at a lower cost than all transformers I had seen in Sweden).



I noticed early that it didn't have galvanic isolation between primary and secondary sides and given that outlets and plugs are not polarized in Sweden. I designed a new box for the transformer with a test button with a red lamp. If lit, then the plug needed to be turned 180 degrees in the outlet in order to operate in a safe manner. The Radio Shack designer of that transformer had evidently taken for granted that the left hole of an outlet is neutral and you can never count on that in Sweden (and in many European countries) and furthermore in theory the pin which was meant to be the left one could also go in the right hole by turning the converter 180 degrees - in short a poor design from electrical safety point of view. But it was a very cheap transformer and it still works even if we don't have the calculator any more.

PS I have an M.Sc.E.E.

I think I've found a solution. There seems to be some dependance on the direction the 100VA supply is plugged into the step-up transformer. One way, we get a potential of 180V between rail and ground. The other way, I see a nice 19V as expected.

I verified the other end of the transformer is correctly connected to neutral as well. Measuring resistance across the coil and coil to coil as well confirmed is configuration too.

Attention!!!
Warrenty disappear if you are not use correct trafo for digital system and for household.
In Canada you must use 120VAC 60Hz for yours CS2.
While at 240VAC is occur for fixed installed equipment.
Only use one trafo for one digital system and another for booster...but they must been at 120VAC system for Canada household!

Hi Tulit,

I think we all can measure a voltage between our tracks and the neutral of the mains, irrespective of the power unit: transformer or SMPS. The measured voltage value depends on the insulation resistance of the transfo/SMPS and of the voltmeter resistance (and of the mains value).
But the available current is quite low: some tens of uA, hence there is no safety problem if your fingers get in contact with both the track and the mains neutral or earth, whatever the direction the transfo/SMPS is plugged into the mains.

Hi!
AFAIK you can select one out of three power sources in the CS2: 60 VA transformer (16 V AC), 60 VA power supply (19 V DC), or 100 VA power supply (19 V DC).
Makes a difference with respect to switching off in overload situations.

So using a 32 VA transformer and running three trains could lead to the transformer switching off (overload) - the CS2 will show a black screen (without proper shutdown).
While a 6646 may do for a Xmas tree layout with a single running train, it won't do for a large layout.

Hi. This was my assumption too but it`s definitely noticeable depending on how well your body is grounded. With the plug reversed, the issue has gone away.

Hi . Yup it definitely says 220-240V. I`ll try and take a picture of the sticker tonight. But I agree, for all intensive purpose it should be fine. Most residential services are +/-5% anyways.