Electrification time voltage

The measurements, at nine discrete temperatures, were performed with an electrification voltage of 500 Volt and an electrification time of thirty minutes. The measured currents were used to calculate the so-called p-60 value and the p-dc value, see 5.1.5. 

All measurements were performed with an electrification voltage of 1000 Volt and an electrification time of twenty minutes. This electrification time proved to be sufficient to avoid contributions of time dependent charging currents (see Chapter 5.1). The in this way performed measurements agree with the recommendations given in ASTM D257 and IEC 93 methods. 

Resistivity is sensitive to temperature and humidity, and tests are usually made after conditioning in the standard atmosphere of 23 2°C and 50 5%RH. Surface resistivity is particularly sensitive to humidity and the standard humidity should be maintained during the test. Where results are to be used as design or performance data, it would be advisable to test over a range of humidities and (perhaps) temperatures. The resistance of the test piece is measured after the test voltage has been applied for a set period, usually 1 min, although this will very often not be an adequate time for the current, and hence the measured resistivity, to reach an equilibrium value. If it is suspected that this is the case, resistivity can be monitored as a function of time of electrification. 

Electric strength is usually taken as the nominal voltage gradient (applied voltage divided by test piece thickness) at which breakdown occurs under specified conditions of test. These specified conditions of test are important as the measured electric strength is not an intrinsic property of the material but depends on test piece thickness, time of electrification and the electrode geometry, as well as on conditioning of the material. 

The time of electrification, unless otherwise specified, should be 60 s and the applied direct voltage = 500 5 V. 

Volume Resistivity or Conductivity Measure the dimensions of the electrodes and width of the guard gap, g, accurately. Unless otherwise specified, the time of electrification should be 60 s, and the applied direct voltage... 

Surface Resistivity or Conductivity The electrode dimensions and the distance between the electrodes, g, are to be measured accurately. The surface resistance or conductance between electrodes No. 1 and 2 is measured with a suitable device [Brown, 1981]. The time of electrification should be 60 s and the applied direct voltage shall be 500 5 V. 

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