| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an error-compensated current transformer which can effectively compensate an error caused from the exciting impedance of the current transformer regardless of a value of a load connected to the current transformer. <P>SOLUTION: The error-compensated current transformer includes the transformer CT which has a primary winding that a current to be measured flows, and a secondary winding that is connected with a load resistance Zb and applies a current introduced in correspondence to the current to be measured for the load resistance; and a computable amplifier OA which performs a computation using a voltage signal produced on the load resistance to compensate the exciting voltage Ve of the transformer. The error-compensated current transformer includes a compensatory voltage-dividing resistor Zs' which has the same resistance to the load resistance and is connected to the load resistance in series, and compensation circuits OA1-OA3 which computes a compensating voltage demagnetizing the exciting voltage on the basis of a second voltage extracted from the series resistance of the load resistance and compensatory voltage-diving resistance. The exciting voltage of the transformer is compensated by using the compensating voltage. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
