Experimental investigation on the measurement deviations in recording brush discharges from insulating surfaces by Coulombmeters

The total charge on a charged sheet before and after a provoked brush discharge, their difference “C”, the induced charge “A” on different probes immediately before the discharge and their transferred charge “B” measured by commercially available Coulombmeters have been measured for probes from 2 mm to 25 mm in diameter including human thumb and shielded probe. The brush discharges were provoked on PTFE discs 10 cm–20 cm. The results obtained can be used for correct estimation of the incendivity of brush discharges between 10 nC and 90 nC.

► Authors measured charge on a sheet before and after provoking a brush discharge.
► They additionally measured the transferred charge with a hand-Coulombmeter.
► They compared measured transferred charge with measured charge loss on the sheet.
► They found an acceptable low difference between both.
► Transferred charge corresponds better with discharge incendivity than charge loss.