Assessing the significance of surface electric potential values displayed by a non-contact electrostatic voltmeter in five situations of practical interest

Accumulation of electric charges, which is advantageously used in various industrial applications, can also be a major source of damage for the electronic devices and systems. Electric field or potential measurements can directly assess the electrostatic hazard, i.e. to evaluate the risks associated with electric charge generation, accumulation, and discharge in various circumstances. The aim of this work was to assess the significance of the results of electric potential measurements carried out with the non-contact probe of an electrostatic voltmeter at the surface of insulating bodies, in configurations that mimic various situations of practical interest, more particularly those related to monitoring of charge build-up in operating pneumatic transportation pipes for particulate matter or in the various elements of vacuum cleaners (floor brush/roller, telescopic tube, hose, dust collector, …). The experiments were conducted with corona-charged 25 cm² square-shaped polypropylene (PP) slabs and mm-sized granules. The PP slabs were placed in various positions with respect to the ground and to the non-contact probe. In two situations, the charged PP granules were in or moved through the airgap between the slab and the grounded electrode. The results show that the non-contact probe can detect each change of situation, as the potential measured by the electrostatic probe is the superposition of the effects produced by two charge distributions, on the slab and on the granules.