Summary
The paper presents electro-optic Kerr effect measurements of electric field distributions at DC voltage in mineral oil. The so-called AC modulation method is used to reduce measurement errors. For that, a small AC voltage is modulated on the DC voltage. Frequency and amplitude of the AC voltage must not influence the DC field distribution. The test setup and the measurement principle are presented. The Kerr constant was determined to minimize measurement errors and to calibrate the test setup. Therefore, various AC voltages were applied to a stainless steel parallel-plate electrode configuration in the centre of an oil-filled test vessel. Due to the calibration by using different AC voltages, the influence of space charges on the determination of the Kerr constant is negligible. It is important to use a parallel-plate electrode configuration to ensure a constant field distribution along the effective light propagation path. Here, the Kerr constant was identified to be 0.8×10-15 m/V2. DC field measurements were done at different oil gap spaces and various DC field strengths by changing magnitude and polarity of the applied DC voltage. So, the influence of the applied voltage and the gap space to the electric field distribution was evaluated. The enhancement of the electric field strength up to the factor 1.2 of the mean DC electric field is measured in front of the anode. However, the measurement results imply a majority of negative charge carries in the specimen. An error analysis gives information about measurement accuracy. The maximum measurement error caused by the measurement system is about 1.6 %. Therefore, comparatively good experimental conditions were ensured. The error caused by the influence of the geometric edge effect of the electrodes was also calculated. It is about 1.6 % and is negligible for investigations of mineral oil in the given parallel-plate electrode configuration.
Additional informations
| Publication type | ISH Collection |
|---|---|
| Reference | ISH2017_197 |
| Publication year | |
| Publisher | ISH |
| File size | 990 KB |
| Pages number | 6 |
| Price for non member | Free |
| Price for member | Free |
Authors
NODA, FUTAKATA, Andersson
