Hi John et al, maybe you can see this picture? Not a schematic but a picture from EBAY of some one selling one just like mine with it showing the plate. #1, #3, and #4 are on the copper core side and #'s 2 and 5 are on the shaft side. Plus here is something else I found on the WEB elsewhere talking about transformers. I think it confirms what bigredc was saying although this is really hard to follow??
bigredc, I think this answers the question you had about the schematic relating to #'s 2 and 4...
1) The line voltage is placed across the two endpoint taps: this gives you a maximum output voltage equal to line voltage.
The wiring of most of these is very similar. With luck, along with the terminal numbers, there is a graphic which respresents the coil. Think of this as a single winding with four fixed taps, and one sliding tap. Two of the fixed taps are the endpoints of the winding. The other two taps are placed about 18% from each of the endpoints. The sliding tap is where you pick off your variable voltage. When installing, you have two choices in common practice. (1) The line voltage is placed across the two endpoint taps: this gives you a maximum output voltage equal to line voltage. Generally the line neutral is attached to the endpoint nearest the "0" setting of the dial, and hot is placed on the endpoint nearer the "100/120/140" setting, the output voltage is then picked off between neutral and the sliding tap. (2) The line neutral is connected to the endpoint near "0" as in (1), and line hot is attached to the tap ~%18 away from the endpoint nearest the "100/120/140" setting. This gives the autotransformer a bit of a "tail" above the hot connection, and it is this tail that gives you the ability to get a higher-than-line output voltage. The output voltage is picked off between neutral and the sliding tap, the high endpoint is not explicitely connected in this arrangement: though you will measure ~140V here with a voltmeter. It may also be possible to get even more voltage by connecting line voltage across both of the "inside" taps, and picking output off between the "0" endpoint and the sliding tap, but I have not seen this done. If you cannot determine which terminal is which by inspection or by the legend, you may be able to figure it out with an ohmeter: obviously resistance should be greatest across the endpoints. But because you are dealing with fairly heavy gauge copper wire, you need a sensitive ohmeter: .1 ohm resolution might cut it, but I doubt it: probably .01 ohm or better resolution is needed.
I tried the ohmeter but was not able to interperate the results.
So if I undersand this #1 is white as bigredc said and the hot line (black) will be combined so as to put #'s 2 and 4 together and the output will be the result of where the #3 sweep is on the dial. Still seems funny cause of the way the arrows are on the diagram/schematic
Last edited by walt1122; 05-16-2011 at 10:31 PM.