| 摘要 |
PROBLEM TO BE SOLVED: To constitute a load-circuit protective device with which electric power and electrical energy can be measured without installing a current transformer and a voltage transformer for electric power measurement when an electric power measuring function is added to the load-circuit protective device. SOLUTION: The load-circuit protective device is provided with the current transformer used to detect a load current of a load circuit to which a load having a small load change such as a motor or the like is connected, a storage means to which a voltage and a power factor of the load circuit are input, and a computing means which computes the electric power on the basis of the stored voltage and the stored power factor and on the basis of the load current detected by the current transformer equipped at the protective device. The protective device is constituted in such a way that, in a state that an ordinary load is applied, the voltage and the power factor of the load circuit are measured and stored, that the electric power is computed on the basis of the stored voltage and the stored power factor and on the basis of a measured value of the load current of the load circuit measured by the current transformer, and that the computed electric power is integrated so as to compute the electrical energy. COPYRIGHT: (C)2003,JPO
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