| 摘要 |
PURPOSE:To omit winding operations which otherwise would be required for each iron core and to eliminate the need of regulating an input voltage in a testing apparatus for testing AC magnetization properties of toroidal cores, by negatively feeding back a part of an output voltage of the secondary winding to the primary winding. CONSTITUTION:Power from an AC power supply 2 is applied to terminals P1 and P2 of the primary winding W1 of a toroidal core 1 via an amplifier 5, an AC ammeter 3 and a wattmeter W. Terminals S1 and S2 of the secondary winding W2 of the toroidal core 1 are connected with an AC voltmeter and 4 also with said wattmeter W. Further, the terminal P2 is connected directly with the terminal S2, while the terminal S1 is connected with a feedback circuit consisting of a phase regulating circuit 7 and a feedback resistor 6 one end of which is connected to an input terminal of said amplifier 5. According to such constitution, variation in output voltage Es can be reduced. Therefore, even if there occurs any variance in a DC resistance value due to a contact, or an equivalent AC resistance value or DC resistance value of the primary winding W1, it is substantially unnecessary to regulate the input voltage. As a result, there is substantially no distortion in the waveform of magnetic flux in the iron core 1, namely in the output voltage Es.
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