Insulators, breakdown voltage

For dc input voltages that are more than 100 VDC, a layer of Mylar tape should be placed between primary and the secondary(ies) and between any multiple secondaries. One should not completely trust the insulation breakdown voltage rating of the magnet wire since it could nick during the winding process. 

Insulators, breakdown voltage, 15-42 to 46 Integral tables, A-15 to 46 Integration, methods and techniques, A-11 to 15... 

ASTM D149, Test Methodsfor Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials at Commercial Power Frequencies, Vol. 8.01, ASTM, Philadelphia, Pa., 1987. 

The procedure will be the same as that discussed for switchgear assemblies (Section 14.3.3). The test voltage may be applied for one minute as shown in Tables 32.1 (A) or (B) for series I and Table 32.2 for series II voltage systems. Any disruptive discharge or insulation breakdown during the application of high voltage will be considered to be dielectric failure. 

Grain boundary defects are primarily responsible for the operation of zinc oxide (ZnO) varistors, a shortened form of variable resistor. The varistor behaves like an insulator or poor semiconductor at lower electrical field strengths, but at a critical breakdown voltage the resistance decreases enormously and the material behaves like an electrical conductor (Fig. 3.36). When a varistor is connected in parallel with electrical equipment, negligible power flows through it under normal low... 

ASTM D149, 97 (2004). Standard test method for dielectric breakdown voltage and dielectric strength of electrical insulating materials at commercial power frequencies. 

Polymeric materials usually have low dielectric breakdown voltages. Fortunately, the electrical insulation property of PDMS is sufficient (R > 1015 O/cm) [159]. Moreover, the use of a lower electric field ( 1100 V/cm) helps alleviate this... 

A native oxide layer on an n-type mercury cadmium telluride substrate 11 is used in combination with ZnS to provide first level insulation 12. The ZnS is deposited by thermal evaporation and an opaque field plate is provided for signal channel definition. Second level insulation of ZnS is deposited. This layer is thicker than the first level, and is provided with a stepped or sloped geometry under the first level gates. Input and output diodes are provided with MIS guard rings to increase breakdown voltages. 

Lubricant film between the moving parts generally provides an electrical insulation, and breakdown voltage ranges between 30 and 50 V. Electrical bridges may form due to soiling, metal particles, or insufficient lubricant. 

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