| 摘要 |
<p>769.001 S P E C I F I C A T I O N GKP VARIABLE TRANSFORMER METHOD /A APPARATUS Inventor : Stanley G. Peschel In a variable transformer, two high-conductivity brushes are mounted in carriage means and adapted for longitudinally traversing the transformer winding to contact exposed segments of the winding which are relatively elevated with respect to portions of the nearby turns. By relatively elevating and exposing the odd and even turns along two different traverse paths contact with the individual odd and even¦ turns is obtained by the dual brush system without short-cir-cuiting adjoining turns, the brushes being interconnected through an external current-limiting or compensating circuit. Spacings between exposed segments of the winding along these respective traverse paths are filled with dielectric potting material and are wider than the high-conductivity brushes; thus these brushes can never short circuit adjacent turns. The brushes are positioned in the carriage relative to each other and relative to exposed winding segments so that at all times at least one of the brushes contacts an exposed winding segment. Potential differences between exposed winding segments contacted by respective brushes are offset by the voltage difference compensating circuit, such as a diode circuit, connected between the brushes, whereby no turn-to-turn current can flow, irrespective of the external load conditions being applied to this compensating circuit. Preferably, the winding or windings are of copper wire having a square or rectangular cross section, and the high-conductivity brushes are also formed of copper. Further, the winding or windings are advantageously closely coupled to the magnetically permeable core of the variable transformer, thereby minimizing leakage flux and associated leakage reactance. Very large size variable transformers now become feasible by employing this invention.</p> |
