摘要:
Polymer concrete electrical insulation including a hardened epoxy resin composition filled with an electrically non-conductive inorganic filler compositions. The polymer concrete electrical insulation system optionally may contain additives. The epoxy resin composition is based on a cycloaliphatic epoxy resin. The inorganic filler composition can be present within the range of about 76% by weight to about 86% by weight, calculated to the total weight of the polymer concrete electrical insulation system. The inorganic filler composition includes a uniform mixture of (i) an inorganic filler with an average grain size within the range of 1 micron (μm) to 100 micron (μm) [component c(i)], and (ii) an inorganic filler with an average grain size within the range of 0.1 mm (100 micron) to 2 mm [component c(ii)]. The inorganic filler with an average grain size within the range of 1 micron (μm) to 100 micron (μm) [component c(i)] can be present in an amount within the range of 22% to 42%, calculated to the total weight of the polymer concrete electrical insulation system; and (e) the inorganic filler with an average grain size within the range of 0.1 mm to 2 mm [component c(ii)] is present within the range of 41% to 61% by weight, calculated to the total weight of the polymer concrete electrical insulation; and method of producing said electrical insulation.
摘要:
Exemplary embodiments are directed to a device with overvoltage protection that includes a varistor which can be connected by a first connection via a first line to high-voltage potential in a circuit arrangement, while a second connection is connected to ground via a second line. Furthermore, an additional impedance is provided, which can be connected between the second connection and ground or the first connection and the high voltage, or is mounted fixed in this position. The corresponding line can be interrupted by a switching arrangement. In order to test the withstand voltage of the circuit arrangement, at least one of the first and second line is interrupted and an additional impedance is inserted. A test voltage is applied to the circuit arrangement. After the overvoltage test, the interruption in at least one of the first and second lines is removed again.
摘要:
The manufacturing method for an electroceramic component (1), for example a varistor (1), comprises a laser irradiation of a part (5; 6) of the surface of an electroceramic body (2) before a metallization (3; 4) is applied to the part (5; 6) of the surface. By means of the laser irradiation it is possible to produce a micro-roughness and/or a chemical modification of the surface which permits good adhesion of the metallization, and it is possible to reduce or eliminate areas of unevenness or waviness of that part (5; 6) of the surface of the electroceramic body (2) which is to be metallized. In addition, improved transverse conductivity can be produced, by virtue of which a low contact resistance and a very homogeneous current distribution is achieved, in particular near to the metallization (3; 4). In addition it is possible to remove residues which originate in particular from a sinter support or from the application of a passivation layer. After the laser irradiation, the electroceramic body advantageously has a border (9) which adjoins the part (5; 6) of the surface and which is not laser-irradiated. The laser beam can advantageously be pulsed and focused.
摘要:
A fuse has a fuse element (6), composed of silver, with constrictions (7) which follow one another at regular intervals, and which fuse element makes contact with a combustible element (8), preferably over its entire length. The combustible element (8) is composed of a combustion compound, which is essentially of a fuel such as guanidine or a guanidine derivative and a metal such as Mg or Al and an oxidant such as KNO3, NaNO3, NH4NO3, KClO4, NaClO4, KMnO4, the proportion of which is overstoichiometric by a factor of at least 1.1, and preferably of at least 10. The combustible compound also preferably contains a binding agent such as paraffin, a thermoplastic or an elastomer, so that it can be extruded. It has an ignition temperature of between 160° C. and 260° C. and emits more than 200 J/g of heat, so that it ignites even in the event of small overcurrents and melts the entire length of the fuse element (6).
摘要:
The electrical resistance element (10) includes a resistance body (3), which is arranged between two plane-parallel, pressurized electrodes (1, 2), has PTC behavior and comprises a polymer matrix and two filler components of electrically conducting particles embedded into the polymer matrix (4).When a short-circuit current occurs, the resistivity of the resistance body (3) changes abruptly above a temperature limit value in a surface layer resting on the electrodes and containing at least a first of the two filler components. A second of the two filler components is selected such that a composite material containing at least the polymer matrix and the second filler component has PTC behavior, with an abruptly changing behavior greater by at least one order of magnitude in comparison with the surface layer. At the same time, this composite material has a resistivity which is lower by at least one order of magnitude than a composite material formed by the polymer matrix and the first filler component.The resistance element has a high nominal current carrying capacity and can limit large short-circuit currents permanently.
摘要:
A current-limiting component having an electrical resistance body arranged between two contact terminals. The resistance body contains a first resistance material having PTC behavior. Below a limit temperature, the first resistance material has a low cold resistivity and at least one current-carrying path extending between the two contact terminals. Above the limit temperature, the first resistance material has a high hot resistivity compared with its cold resistivity. The current-limiting component has uniform switching capability and high rated current-carrying capacity despite simple and inexpensive construction. The resistance body additionally contains second resistance material having a resistivity which is between the cold resistivity and the hot resistivity of the first resistance material. The second resistance material is in intimate electrical contact with the first resistance material and forms at least one resistance path connected in parallel with the current-carrying path.
摘要:
Electrical insulation system with improved electrical breakdown strength, including a hardened polymer component having incorporated therein a filler material and a nano-scale sized filler material. The hardened polymer component is selected from epoxy resin compositions, polyesters, polyamides, polybutylene terephthalate, polyurethanes and polydicyclo-pentadiene. The filler material has an average particle size within the range of 1 μm-500 μm, and is present in a quantity within the range of 40%-65% by weight, calculated to the total weight of the insulation system. The nano-scale sized filler material is a pretreated nano-scale sized filler material, having been produced by a sol-gel process. The nano-scale sized filler material is present within the electrical insulation system in an amount of about 1%-20% by weight, calculated to the weight of the filler material present in the electrical insulation system.
摘要:
Exemplary embodiments are directed to a power electronic device with an electronic device including a substrate, a metal layer formed on the substrate and a field grading means located along an edge of the metal layer. The field grading means has a non-linear electrical resistivity.
摘要:
The present invention relates to a varistor material for a surge arrester with target switching field strength ranging from 250 to 400 V/mm comprising ZnO forming a ZnO phase and Bi expressed as Bi2O3 forming an intergranular bismuth oxide phase, said varistor material further comprising a spinel phase, characterized in that the amount of a pyrochlore phase comprised in the varistor material is such, that the ratio of the pyrochlore phase to the spinel phase is less than 0.15:1.
摘要:
The disclosure relates to an overvoltage protection means containing ZnO microvaristor particles for protecting electrical elements and a method to produce the means. Single microvaristor particles are placed in an arrangement having a monolayer thickness and are electrically coupled to the electrical element to protect it against overvoltages. Embodiments, among other things, relate to: 1-dimensional or 2-dimensional arrangements of microvaristor particles; placement of single microvaristors on a carrier; the carrier being planar or string-like, being structured, being a sticky tape, having fixation means for fixing the microvaristors, or having electrical coupling means. The monolayered overvoltage protection means allows very tight integration and high flexibility in shaping and adapting it to the electric or electronic element. Furthermore, reduced capacitance and hence reaction times of overvoltage protection are achieved.