| 摘要 |
<p>PURPOSE:To obtain an error compensating current transformer which contrives improvement in errors by feeding an current in order to generate offsetting voltage which offsets voltage generated by the secondary leakage impedance of secondary winding to a compensating impedance that is connected to the secondary winding according to the output of an active element which makes voltage that is measured at the load side by the compensating impedance almost zero. CONSTITUTION:A current source 23 makes up a compensating means and mainly it is composed of NPN transistors 25 and 27 which are connected complementarily. Then, base terminals of both transistors are connected to the output of an operational amplifier 4 and further, emitter terminals of them are connected between the output terminal 5 of secondary winding 3 and a compensating impedance ZC and on the other hand, collector terminals are connected to a required positive current source (+VCC) as well as negative current source (-VEE) through respective resistors 29 and 31. Consequently, a feedback current IC flows through the compensating impedance ZC and then, its current and voltage I2Z2 generated by the secondary leakage impedance Z2 offset each other. In this way, error compensation is performed.</p> |
