Electrical tests volume resistivity

DIN lEC 60093, Methods of Test for Insulating Materials for Electrical Purposes Volume Resistivity and Surface Resistivity of Solid Electrical Insulating Materials, 1993. 

DIN lEC 60093, Methods of test for insulating materials for electrical purposes Volume resistivity and surface resistivity of solid electrical insulating materials, 1993. 

Electromagnetic interference (EMI) testing has become more prevalent for materials that either emit or are affected by EMI. Shielding efficiency (SE) of materials is deterrnined by measuring electric field strength between a transmitter and receiver with or without the presence of the material under test. Several researchers have suggested a correlation between volume resistivity and SE values (300,301). 

Because the surface of rubbers may conduct electricity more easily than the bulk of the material, it is usual to distinguish between volume resistivity and surface resistivity. Volume resistivity is defined as the electrical resistance between opposite faces of a unit cube, whereas surface resistivity is defined as the resistance between opposite sides of a square on the surface. Resistivity is occasionally called specific resistance. Insulation resistance is the resistance measured between any two particular electrodes on or in the rubber and, hence, is a function of both surface and volume resistivities and of the test piece geometry. Conductance and conductivity are simply the reciprocals of resistance and resistivity respectively. 

Standard test method for rubber property-volume resistivity of electrically conductive and antistatic products Specification for electrical properties of conducting and antistatic products made from flexible polymeric material... 

Electrical Properties. The electrical properties of silicone gels are essentially the same as those of most clean, unfilled silicone elastomers and fluids. Typical values for dielectric constant and dissipation factor when tested at 25°C and 100 Hz are 2.7 to 2.9 and 0.001 to 0.002 respectively. Volume resistivity values, usually, fall in the 10 ohm- centimeter range. 

The Ki-value determination of PVC cable compounds The specific volume resistivity is the most important electrical property of an electrical grade PVC. It is measured on a heavily plasticised product, the cable compound, pressed to a 2 mm. thick sample sheet. Cable manufactures usually test the resistivity of these compounds on cable samples and express the results in a so-called Ki-value. The Ki-value is in fact a volume resistivity value (see below) but measured on a cable sample with tapwater as low potential measuring electrode. A series of Ki-value determinations was performed to investigate the different parameters influencing this quantity. 

Electrical Tests. Dielectric constant, dielectric strength, volume resistivity, power loss, power factor. 

Electrical properties such as volume resistivity and surface resistivity of blend samples are furnished. Blend with 30 phr carbon black was found to be overloaded in terms of both volume resistivity and surface resistivity. That is, the resistivity of these formulations was lower than the limit of the testing equipment. This is an effect of the quasigraphitic microstmcture of the carbon black this makes the blend more electrically conductive. The higher the surface/volume resistivity, the lower the leakage current and the less conductive the material is. The major application of carbon black... 

FIGURE 3.90 Test for DC resistance of insulating materials. Electrical resistance of specimen (ohm) = applied voltage (V)/current measured A). Volume resistivity (ohm-cm) = resistance of specimen (ohm) Xarc of upper electrode (cm )/specimen thickness (cm). Standard test methods ASTM D257, BS 2782 method 202. 

To function as electrical conductors, epoxies and other polymer resins, because they are inherently insulators, must be filled with electrically conductive particles such as metals. The selection of electrically conductive or insulative adhesives is based largely on their conductivities or, conversely, on their volume resistivities. Electrically conductive adhesives should have low resistivities initially and retain those values on aging, moisture exposure, thermal cycling, and other operating and test conditions. The resistivities of metal-filled epoxy adhesives can range from... 

The main electrical properties related to organic materials are volume resistivity (for both conductive and nonconductive adhesives) and dielectric constant and dissipation factor (for insulative materials). Other electrical tests for conductive materials that are more application specific are electrical stability, current-carrying capacity, and interconnect resistance. 

The electrical conductivity data of grease was obtained by volume resistivity test cells made by Electro-Tech Systems, Inc. (ETS) [27]. The cell dimensions automatically calculate the volume resistivity of the material being tested by multiplying the measured resistance by either 10 (large cell) or 100 (small cell). The stainless-steel container acts as both an electrostatic shield and provides containment of material overflow. The test cell is made from PVC and uses stainless-steel electrodes. Figure 19.4 shows a diagram of the test cell. 

DC Resistance or Conductance of Insulating Materials. Primary Film Test Method ASTM D257 Additional Test Method lEC 60093. The test method ASTM D257 covers direct-current (DC) procedures for the determination of insulation resistance, volume resistance, volume resistivity, surface resistance, and surface resistivity of electrical insulating materials, or the corresponding conductances and conductivities. 

BS 4618, Recommendations for the Presentation of Plastics Design Data. Part 2. Electrical Properties, Section 2. 3 Volume Resistivity Section 2.4 Surface Resistivity (London, 1975) BS 5102, Phenolic Resin Bonded Paper Laminated Sheets for Electrical Applications (London, 1974) BS 5762, Methods for Crack Opening Displacement Testing (British Standards Institution, London, 1979)... 

Plastics—Determination of the Fluidity of Plastics Using Capillary and Slit Die Rheometers Plastics—Determination of Fracture Toughness (Gc and Kq). Part 1 Linear Elastic Fracture Mechanics (LEFM) Approach Methods of Test for Volume Resistivity and Surface Resistivity of Solids Electrical Insulating Materials... 

The electrical resistance of plastics is commonly measured both through the volume of the plastic (known as volume resistivity, ASTM D257) and on the surface of the plastic (known as surface resistivity). The term for volume resistivity is ohm-cm, and the term for surface resistibility is ohms per square. Both terms are derived from a mathematical expression based on the dimensions of the test piece and the resistance measured for that test piece. 

D257, tests for electrical resistance, insulation resistance, volume resistivity, volume resistance... 

Table 3 compares properties of PTT, PET, and PBT (40). They were measured on injection-molded samples using ASTM test methods. Tensile strength, flexural modulus, and notched Izod impact of PTT fall in between those of PET and PBT. All three polymers have similar electrical properties except for PET which has lower volume resistivity. The lower moisture absorptions of PTT and PBT are due to the high crystallinities from fast crystallization. 

Standard testing of electrical properties of plastics includes dielectric strength, permittivity, dissipation factor, smface and volume resistivity, and arc resistance. Dielectric strength is the maximmn voltage required for breakdown and is determined by one of three techniques short-time, slow-rate or slow-rise, and step-by-step. The two last techniques use data from the short-time test to... 

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