It's one of these: tp://www.sky-chaser.com/image/tesla/tcnst1.jpgo far I have assumed that the two large terminals are the output (on opposite sides of the box) and the three smaller terminals running down one side are inputs >raised) and earth.s there an 'official' diagram somewhere?
You assume correctly. The "official" way to check, using an ohm meter, is to measure the DC resistance of each terminal in relationship to each other, and to the case. What you should find is that the secondaries have a higher resistance relative to the primary (my 15kV/60mA France measures about 3k ohm each to the case, about 6k ohm to each other), with the primary being on the order of maybe an ohm or two. You should also find that the primary is not tied into to the case.
The reason for this is due to the transformer being a step up transformer. For a 120VAC in, 12kV out transformer, there is a 1:100 ratio in the voltage in/out, which corresponds directly to the actual turns ratio of wire wrapped around the unit.
The primary side (120VAC) must supply more current, so it is a larger gauge wire with fewer turns (less resistance). The secondary, however, has 100 times more turns, and as it does not carry as much current (on the order of tens of milliamperes, mainly 30 or 60, occasionally 120mA units are seen), uses a much smaller wire (the size of your hair) and will have a much higher resistance.
You will find that all transformers behave according to this model, be they step up transformers, as yours is, or step down transformers (which work the opposite way, to step down voltage).
Jon _______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla