| 摘要 |
<p>A method is used for providing overvoltage protection for the terminals of a tapped transformer and it protects the switches when a load is switched from one power transformer tapping terminal to another, and it may be arranged in several slightly different alternative forms. A power transformer winding (1) has tappings (2, 3) which may be switched alternatively to a load line (7) via a gauged switch (5, 6). To prevent voltage overload during switching, a vacuum cell (12) and resistances (8, 9), together with switch contacts (10, 11) gauged to the main switch (5, 6) are incorporated in the circuit, so that a discharge in the cell prevents voltages above a certain defined value developing. A voltage dependent resistance (14) may be incorporated in the circuit.</p> |
