With respect to what? You have three choices: primary (total winding), secondary (wiper to neutral), and upside-down (wiper to hot).
In any case, taking a consistent comparison, the leakage won't be much worse in one position than any other, though I expect it will be minimal in the middle, and maximal towards the ends (following a gentle parabolic curve inbetween). I would think the difference to be small, perhaps 20%.
(I think the "consistent" method would be, one half (hot to wiper) with respect to the other half (wiper to neutral), adjusted for turns ratio. This uses it as a normal transformer (that happens to have a common point tied between the two windings), so the measured value is reasonable with respect to regular transformers.)
I wouldn't expect it to be very useful at frequencies over a few kHz, if that's what you're thinking..?
As an autoformer, the output current capacity (including surge/fault capacity) and regulation (series equivalent impedance) are quite good. Most pronounced for high ratios (above, say, 25%), you get the divider effect in addition to the transformer effect, or in other words, a lot of output current flows in series through the top half of the winding, as well as being sourced from the bottom half of the winding. Of course, at ~100%, all the current is sourced from the hot wire, and there's no series impedance. (You're still limited in current by the size of the wire, of course.)
Tim
Home
Help
Search
Login
Register
