Original poster: "Gerry Reynolds" <gerryreynolds@xxxxxxxxxxxxx> Hi Christoph,Your connection is exactly what the filter designers intended. The filter is to keep stuff from the load from getting to the line. There are filters that have two common mode chokes (turn common mode stuff into differential mode stuff and visa versa) so they could filter differential mode stuff out equally in both directions if Y caps to ground are located at the center nodes between the two chokes. If Y caps across the line are symetrically placed, the common mode stuff will be equally filtered in both directions as well. My filter has line to line caps in only two places (line end and center nodes between the two chokes) but could easily be modified by adding a Y cap (caps designed to fail open if they fail) across the lines at the load end to make it equally bi directional (not an issue for most TC service). The Y caps from each line to green wire ground are located at the center nodes of the filter and therefore this is symetrical. This caps to ground must not be augmented with external caps else safety regs regarding the maximum green wire current could be exceeded.
Gerry R.
Original poster: "Christoph Bohr" <cb@xxxxxxxxxxxxxxx> Hello folks. I use a line filter between my HV-xformer and the power controller ( wanted to keep the nasty stuff out as soon as possible ) Everything works fine for ober a year now, but yesterday I became unsure about the way I installed the filter. Here is a drawing of what is printed on the filter: http://www.luebke-lands.de/media/Filter.jpg BTW the filter is a Siemenst SiFi-B B84112-B-B120 25/085/21 20A 110/230V 50Hz The load end is connected to the HV transformer, the "line" side goes to the variac going to mains. I wonder, if this is right or wrong as I don't know if this filter was originally intended to keep noise out from sensitive equipment or keep it in from noise- producing equipment... I am sure someone on the list knows better ;-) regards Christoph Bohr