ソレノイドの不良品検査

概要

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Solenoid coils were inspected whether they were inferior or not. Normal solenoid coil has a self-inductance L=287 mH at a frequency of 1 kHz and a resistance R_L=425 Ω. It has also a stray caoacitance C_L, so an LCR serial resonance is supposed to occur, if current is supplied to the coil. The circuit was devised to cause the serial resonance, and waveforms of its damping oscillation were observed with a digital storage oscilloscope. Specimens were originally classified as normal ones, impulse corona inferior ones, inferior ones due to broken wire, and layer shorted inferior ones. With our method, normal solenoid coils were easily discriminated from inferior ones. For further investigation, however, more quantitative measurements were performed. On waveforms of damping oscillation were measured physical quantities, such as a maximum voltage attained V_<max>, 3 resonance period T, a damping time constant T_<damp>, a stray capacitance of solenoid coil C_L, and a junction capacitance of FET C_<DS>. Based on these quantities, the difference in waveforms was analyzed and discussed.
帝京平成大学の論文
2003-12-25