| 摘要 |
PURPOSE:To detect short circuit of a coil turn of an electromagnetic induction device without overlooking even one turn by applying a voltage to one coil of the electromagnetic induction device and observing a change in its exciting current waveform. CONSTITUTION:From a power supply, a voltage is applied to a coil of a test sample voltage transformer 1, and its voltage waveform and current waveform are observed on oscilloscopes 5 and 6 through a transformer 3 and a shunt 4. If the test sample voltage transformer 1 is sound, its voltage waveform shows a sine wave and its exciting current waveform indicates the waveform containing the 3rd higher harmonic wave. Against this, in the case of the test sample transformer 1 contains 1-turn short circuit, it is not clear concerning its voltage waveform, but concerning its current waveform, it becomes a waveform having much contents for the basic wave, and it is possible to detect existence of coil turn short circuit. Thus, even a small coil turn short circuit can be exactly detected. |
