JCI 166 Sample Support
>A simple box support for layer and fabric samples designed for use with the JCI 155 Charge Decay Test Unit
The JCI 166 Sample Support provides a simple way to hold layer type materials and fabrics and present them to the JCI 155 Charge Decay Test Unit for measurement of charge dissipation performance capabilities. Charge decay measurements are normally made both with the material freely supported with no earth surface directly behind the area tested and also with the sample resting against an earthed backing surface. These two arrangements represent the extreme conditions of practical applications. The longer of the two decay times should be used for assessment of the suitability of the material static charge retained on materials may present a risk in static sensitive situations.
The dimensions of the JCI 166 are 170 x 270 x 60mm. The test aperture on the top side of the JCI 166 is located so that when the JCI 155 is aligned with the sides and the back of the unit it corresponds in position to the test aperture of the JCI 155. This is the ‘open backing’ mounting arrangement. Turning the box round, or offsetting the positions appropriately, provides opportunity for ‘earth backing’ testing. The back plate of the support box is provided with a combination Durable Dot/4mm bayonet pin connector. The unit should be linked to the earth bonding connector on the back plate of the JCI 155 to ensure good equivalence of earthing. This is particularly important when the area of the sample tested is larger than the top surface of the JCI 166.
The JCI 166 Sample Support is appropriate to use in basic tests to measure the charge decay capabilities of materials. With materials that, for example, include conductive threads to help suppress that surface voltage generated by surface electrostatic charge it is appropriate to measure simultaneously the charge received by the sample, the initial peak voltage created by this charge and the rate at which the surface voltage decreases as the charge migrates away. To measure the charge received by layer samples it is appropriate to use the JCI 176 Charge Measuring Sample Support. This enables the ‘capacitance loading’ of surface charge to be calculated [1,2].
[1] J. N. Chubb "The assessment of materials by tribo and corona charging and charge decay measurements" Inst Phys Confr ‘Electrostatics 1999’ Univ. Cambridge, 28-31 March 1999
[2] J. N. Chubb "Measurement of tribo and corona charging features of materials for assessment of risks from static electricity" IEEE-IAS Meeting, Phoenix, Arizona 3-7 Oct, 1999