| 摘要 |
FIELD: electricity.SUBSTANCE: unit with overvoltage protection includes voltage-variable resistor that can be connected by means of the first contact output through the first line to high voltage of electric network, while the second contact output is connected through the second line to earth. Besides, additional resistance is provided, which can be connected between the second contact output and earth or the first contact output and high voltage or rigidly fixed in this position. Corresponding line can be opened by means of switching device. In order to test breakdown strength of electric network, first, the first or the second line is opened and additional resistance is set. Then, test voltage is supplied to electric network. Since voltage drop on voltage-variable resistor is lower than supplied test voltage, voltage-variable resistor overload can be prevented. After overvoltage test is completed, opening of the first and the second lines respectively is stopped.EFFECT: simpler overvoltage test.24 cl, 16 dwg |
