Search

To accurately measure electrostatic discharge energy, a resistive-capacitive voltage discharge approach was used to measure the parasitic capacitance in a circuit. As a result, an output-stage parasitic capacitance in the circuit during the discharge process and a non-negligible storage-stage parasitic capacitance during the charging process were identified. By comparing the data obtained from the resistive-capacitive discharge voltage model and spark current RCL circuit model, the maximum relative deviation from the total circuit capacitance was 5.4% for both approaches. A model based on graded-stage parasitic capacitance was established to analyze the effect of this capacitance on discharge energy. The energy stored in the charging process increased because of the storage-stage parasitic capacitance, and the discharge energy decreased because of the output-stage parasitic capacitance. The energy calculated by the graded parasitic capacitance model was larger than that calculated by the single-stage parasitic capacitance model, with a maximum relative deviation of 36.7% under the test conditions. The smaller the charging capacitor, the more evident the effect of the parasitic capacitance on the discharge energy. • An equivalent model for analyzing parasitic capacitance of the charging and the discharging circuits. • A method for measuring the parasitic capacitance component of the circuit in the resistive-capacitive discharge. • The availability of the proposed procedure is verified by comparison with spark current RCL model. • The method is discussed to produce small energy sparks accurately in MIE test. [ABSTRACT FROM AUTHOR]

A series of electrostatic sparks at different energies are triggered by different methods in testing the minimum ignition energy (MIE) of dust clouds. It is necessary to investigate the difference between actual spark energies and MIEs under different triggering methods. A multi-energy spark generating circuit combined with high-voltage relay (HVR) triggering and electrode movement (EM) triggering was set up to study the effects of triggering types and inductance loads. The first current peak was proposed together with damping ratio and angular frequency of spark current to evaluate the reliability of the experimental results. Results showed that the deviation of spark energy release efficiency between the two triggering types is about 5%–25% when the storage energy was 34 mJ, 110 mJ, 340 mJ and 1100 mJ, which was not enough to cause the difference in the magnitude of MIE. The MIEs of clouds of lemon powder and sea buckthorn powder are consistent using the two triggering types. But the MIE of clouds of lycopodium triggered by EM without inductance is higher than that triggered by HVR. It indicates different triggering types may lead to different MIE results when testing fine dust even if the actual released energy is almost the same. The spark energy release efficiency without inductance is greater than or equal to that with inductance. However, the MIE of lycopodium clouds dropped from 75–90 mJ with no inductance, to 8–10 mJ with a 1 mH inductance. The MIEs of clouds of lemon powder and sea buckthorn powder showed similar trends. • First current peak is proposed to evaluate spark current together with attenuation factor and angular frequency. • The deviation of discharge efficiency of triggering types is not enough to cause the difference in the magnitude of MIE. • Different triggering types may lead to different MIE results when testing fine dust. [ABSTRACT FROM AUTHOR]