Development of automatic volt-ampere characteristic tester for current transformer
Tang Gen-bao · Dianli zidonghua shebei · 2006
The development of an automatic volt-ampere characteristic tester is introduced. Control-led by MCU,the electrical part and the electronic part of the tester work in phase. The inner auto -transformer is driven by servomotor;with different speeds in voltage rising and falling. The voltage and current are measured and converted simultaneously through dual channels and A / D converters to reach the real time performance. The RMS / DC transform before sampling avoids the influence of voltage / current waveform distortion on measurements,which is caused by the iron core saturation of transformer. The proper disposition of the on-resistance of analog switch and the application of digital calibration technique improve the veracity of tester. The precision is better than 0.5 % all over the scale. Using the skill of scale transform,the characteristic curve can be displayed and printed in logarithmic coordinates to show the tiny change of current before saturation. This project is supported by the Technology Program of Zhejiang Province(2005C31069).