404 results about "Dielectric loss factor" patented technology

The invention provides a GPS clock signal-based high voltage capacitive equipment insulation online monitoring system, including an on-site monitoring unit comprising a CPU, a wireless communication module which is 2.4GHz wireless communication module, a GPS clock receiving module, and a on-site monitoring current unit and a on-site monitoring voltage unit installed on the same bus line, and a station terminal control computer. An insulation online monitoring method includes that: the station terminal control computer sends synchronous remotely collection order to each on-site monitoring unit via 2.4GHz wireless network; each on-site monitoring unit receives GPS clock signal and realizes synchronous remotely collection of each on-site monitoring unit on the booking time, comparing the uploaded information, calculates equivalent capacitor, end screen current and dielectric loss factor of high voltage capacitive equipment after the each on-site monitoring unit obtains end screen current signal with clock signal or sequence number and PT secondary side voltage signal.

A magnetic toner having magnetic toner particles containing at least a binder resin and a magnetic material, wherein, in the test of dissolution level of the magnetic material, the dissolution percentages S₃ (% by mass), S₁₅ (% by mass) and S₃₀ (% by mass), and the dissolution level proportion S_c satisfy the following expressions: 0.5≦S₃≦10, 40≦S₁₅≦80, 1.2≦S_c[=(S₁₅−S₃)/(S₃₀−S₁₅)]≦10; and the magnetic toner has a dielectric loss factor (tan δ) at 25° C. and at a frequency 1.0×10⁴ Hz, within the range of from 2.0×10⁻³ or more to 1.5×10⁻² or less.

The invention discloses a method for evaluating ageing state of paper oil insulation. The method is characterized by comprising the following steps of: 1, measuring a relative dielectric constant and a dielectric loss factor of a paper oil insulation test product by adopting a frequency domain dielectric spectroscopy method; 2, establishing a composite exponential function relational expression of the relative dielectric constant and insulation paper polymerization of the paper oil insulation test product, and a composite exponential function relational expression of the dielectric loss factor and the insulation paper polymerization of the paper oil insulation test product; and 3, evaluating the ageing state of a paper oil insulation system by using the relational expressions. A device provided by the invention is simple in structure, is easily implemented, and is greatly improved in accuracy.

A UV-curable acrylate-thiol-ene insulating coating composition for electrical conductors, a method of manufacturing a UV-curable acrylate-thiol-ene insulating coating composition for electrical conductors. The insulating coating being of about 2.5 mum to about 500 mum thickness, which cured coating has a dielectric dissipation factor (60Hz, 24° C.) of lower than about 0.05.

The invention discloses a large-scale generator stator winding major insulation aging state test method based on frequency domain spectroscopy. The method includes the steps: making a generator stop running and be reliably disconnected from a circuit, and cooling the generator to an ambient temperature; testing wiring: connecting a stator winding of the generator with a high-voltage end of a test cable of a dielectric spectrum tester, and connecting a grounding end of a housing of a generator with a grounding end of the test cable of the dielectric spectrum tester; setting a parameter and starting a test; testing a frequency characteristic curve [epsilon]-f of a major insulation complex dielectric constant of the stator winding of the generator, and obtaining the dielectric loss factor increment [delta]tan[delta]N of the current major insulation through calculation by a formula; and evaluating the aging state of the major insulation of the stator winding of the generator according to the obtained dielectric loss factor increment [delta]tan[delta]N. The method is a non-destructive test method, has simple test principles, enables convenient wiring, can accurately determine the dielectric loss factor increment [delta]tan[delta]N of the stator winding of the generator, and thus can effectively evaluate the aging state of the generator.

Curable functionalized imide-linked polyimides compounds have been synthesized that have been found to possess very low dielectric constant and extremely low dissipation factor. These compounds also have a range of high to low modulus, extremely low moisture uptake and are very thermally stable. The combination of these materials in formulation along with functionalized polyethylene, polypropylene, polybutadiens have been found to be ideal for forming films and coatings for the microelectronic applications, multiplayer capacitors and interconnects, and high power cables and wire coatings. The addition of perfluorinated hydrocarbons, and POSS nanoparticles to the formulations have decreased the dielectric constant and dielectric dissipation factor further, and have also improved the flammability of the compositions.

The invention discloses a halogen-free resin composition, a prepreg prepared from the halogen-free resin composition and a laminated board prepared from the halogen-free resin composition and used for a printed circuit. The halogen-free resin composition comprises alkylphenol epoxy resin, benzoxazine resin, an alkylphenol aldehyde curing agent and a phosphorus-contained flame retardant. The molecular structure of alkylphenol epoxy resin adopted in the halogen-free resin composition contains more branched alkyls, so that the halogen-free resin composition is relatively high in glass transition temperature, low in water absorption rate, favorable in heat resistance and excellent in dielectric performance; benzoxazine resin is mixed, so that the dielectric constant, dielectric loss value and water absorption rate of a solid can be further reduced; alkylphenol aldehyde is used as a curing agent, so that the advantages of excellent dielectric performance and low water absorption rate generated by more alkyls in the structure are sufficiently exerted. The prepreg prepared from the halogen-free resin composition and the laminated board prepared from the halogen-free resin composition and used for the printed circuit have the advantages of low dielectric constant, low dielectric loss factor, low water absorption rate, high size stability, high heat resistance, and favorable flame retardance, processability and chemical resistance.

The invention discloses a preparation method of PTFE (Polytetrafluoroethylene) copper clad laminate. The method comprises the following steps: 1, uniformly mixing raw material components of ceramic powder, silane coupling agents, deionized water and PTFE emulsion to form a PTFE glue solution; 2, soaking glass fiber cloth in the PTFE glue solution at a constant speed, and drying to obtain pretreated cloth; 3, superimposing the obtained pretreated cloth and a fluorine resin membrane into a raw substrate with specified thickness, covering the two sides of the raw substrate with copper foil, thenperforming sintering, maintaining pressure and then cooling to room temperature to prepare the PTFE copper clad laminate. The preparation method disclosed by the invention is simple, easy to operate,good in filler dispersion effect, uniform in mixing and good in product size stability. Through reasonable proportion, the prepared PTFE copper clad laminate has different dielectric constants within2.6-8.6 MHz; the dielectric loss factor is smaller than or equal to 0.003; the peeling strength is greater than or equal to 2.2 kN/m, and the comprehensive property meets use requirements and industrialized mass production requirements.

The invention relates to a thermosetting resin composition, a prepreg prepared from the composition, and a laminated board prepared from the composition and used for a printed circuit board. The thermosetting resin composition comprises phosphorus-containing low molecular weight polyphenyl ether resin, epoxy resin, cyanate resin and an accelerator. The prepreg prepared from the resin composition comprises a base material and the thermosetting resin composition which is impregnated and dried and attached to the base material. The laminated board prepared from the resin composition and used for the printed circuit board comprises a plurality of superposed prepregs and metal foils laminated on one side or two sides of the superposed prepregs, wherein each prepreg comprises the base material and the thermosetting resin composition which is impregnated and dried and attached to the base material. The thermosetting resin composition has low dielectric constant and dielectric loss factor and high heat resistance, glass transition temperature, flame retardance and the like; and the laminated board prepared from the composition and used for the printed circuit board has high metal foil peeling strength, heat resistance and dielectric property and is suitable for a high-frequency high-speed electronic circuit board.

A device for producing high power microwave plasmas. The device comprises at least one microwave feed that is surrounded by at least one dielectric tube. A dielectric fluid flows through the space between the microwave feed and the outer dielectric tube. The dielectric fluid has a small dielectric loss factor tan δ in the region of between 10⁻² to 10⁻⁷. A fluid cools at least the outer dielectric tube.

The invention relates to a thermosetting resin composition and a prepreg and a laminate for printed circuits thereby. The thermosetting resin composition comprises at least an epoxy resin with a component being the structural formula (I) and a curing agent. The molecular structure of the epoxy resin composition of the invention contains the low-polarity styrene structure, therefore, the dielectricproperty of the resin is optimized. The dielectric constant and the dielectric loss angle tangent are reduced compared with those of the common epoxy resins. The prepreg obtained by coating the resincomposition on the substrates and the laminate manufactured by laminating the prepreg simultaneously have the characteristics of low dielectric constant, low dielectric dissipation factors, good heatresistance, good dip soldering resistance, good moisture resistance, good humidity resistance and good cohesiveness with copper foils. The resin composition of the invention can be also used for manufacturing the resin sheets, resin composition copper foils, the laminate and the printed circuit boards. R is (a), and n and m are natural numbers.

The invention relates to a method for assessing an insulation state of oil paper based on characteristic quantity of frequency domain dielectric spectroscopy. The method comprises following steps: utilizing a linear medium response equivalent circuit to simulate polarization characteristics of the insulation state of oil paper for a transformer and setting up the relationship between linear medium response equivalent circuit parameters, frequency-domain characterization complex capacitance and dielectric loss factors; then, utilizing complex capacitances with high frequency bands and a parametric equivalent circuit model for dielectric loss characteristic quantity and finally, integrating dielectric loss curves with low frequency bands at prediction sections, wherein the range of frequency bands in a dielectric loss frequency domain is equally divided into n frequency points (n larger than or equal to 1), n frequency points correspond to n dielectric loss integral value and n frequencies and corresponding dielectric loss integral value are fitted to a function curve. The method for assessing an insulation state of oil paper based on characteristic quantity of frequency domain dielectric spectroscopy has following beneficial effects: in order to obtain much more insulation information carried by dielectric loss factors within the limited measurement frequency domain, integrals of dielectric loss factors are utilized in the predicted low-frequency section as characteristic parameters for assessment of insulation state; and dielectric loss integral value within the low-frequency stage obtained by calculations is utilized for determining the insulation aging state of oil paper.

The invention provides a non-fermented dipped seasoned preserved vegetable production method and belongs to the technical field of food processing. The non-fermented dipped seasoned preserved vegetable production method comprises the steps of selecting and slicing specific leaf mustards, then performing pickling and desalination, meanwhile preparing seasoning liquid to enable relative dielectric constant, dielectric loss factor and conductivity of the seasoning liquid at the1Hz frequency to be within a certain range, charging the sliced leaf mustards into a glass jar, dipping the sliced leaf mustards in the seasoning liquid, arranging the whole glass jar in two square parallel plates, connecting the parallel plates to two poles of a power function signal generator, performing processing at room temperature, then taking out and draining the leaf mustards, instantly performing vacuum package with bags, adding sesame oil into the bags, and finally processing products in an ultraviolet radiation sterilization device to obtain finished seasoned preserved vegetable products. The non-fermented dipped seasoned preserved vegetable production method is suitable for production of high-quality non-fermented instant seasoned preserved vegetable and is short in period and standard compared with a traditional process, and due to the fact that materials are carefully selected, the finished products produced by means of the production method are fine and smooth in taste and completely integrate flavored, peppery and salty taste.

The invention discloses a method for measuring dielectric loss factor and insulation resistance of a power transformer. The method aims at resolving the problem that the existing manual mode for disassembling and assembling connection wires costs time and labor and can easily cause measurement errors even safety hazards due to error wire connection. The method includes high voltage relays, a switching switch, a dielectric loss measurement inverse connection module, a dielectric loss measurement face connection module and an insulation resistance measurement module. The method includes that connecting windings on the same side of the transformer and in short circuit with the corresponding high voltage relays with the number of the high voltage relays corresponding to the turn number of the windings of the transformer, switching the high voltage relays of corresponding windings according to the national power industry standard and the test regulation requirement, switching the high voltage relays that the windings to be measured correspond to to high voltage, switching the high voltage relays that the windings not to be measured correspond to to the ground end and utilizing the switching switch to select corresponding modules. The method is capable of achieving automatic measurement, reducing measurement errors, reducing working intensity and improving working efficiency.

The invention provides a resin composition of an insulating layer which has excellent dielectric loss factor, excellent thermal expansion coefficient, excellent elongation at break, surface roughness and peeling strength. The resin composition comprises the components of (A) epoxy resin, (B) active ester compound, (C) carbodiimide compound, (D) thermoplastic resin and (E) inorganic filling material, wherein when the nonvolatile component in the resin composition is set to 100% by mass, the content of the component (E) is above 40%.

The invention discloses an insulation diagnostic method for high-voltage equipment in a charged operating state. According to the method, by means of the electromagnetic induction principle, impact sweep frequency pulse signals output by a frequency conversion power signal source are coupled into the high-voltage equipment through a secondary loop of detected high-voltage equipment, then inductive coupling is carried out on leakage currents after the impact sweep frequency pulse signals are coupled into the detected high-voltage equipment through the loop, and equivalent earth impedance or dielectric loss factors of the high-voltage equipment operating with electricity are calculated by detecting release features of energy generated when the impact sweep frequency pulse signals are coupled and injected to an equivalent electrical loop of the high-voltage equipment, so that whether insulation breakdown discharge to the ground from the high-voltage equipment exists is analyzed. In comparison with the prior art, operating personnel do not need to be close to the primary high-voltage end of the equipment, synchronous transmitting and collecting are carried out by means of a frequency conversion test signal transmitting source and a corresponding receiver, the capacity of resisting disturbance is high, and the insulation state of the high-voltage equipment can be detected with high sensitivity on the condition of not cutting off the electricity.

The present invention relates to a thermosetting low dielectric resin composition, a laminate for use in printed wiring, a laminate for a circuit, and the like. The present invention's thermosetting low dielectric resin composition contains a specific siloxane denatured polyimide, a compound having two or more allyl or methylallyl groups, and a compound having two or more maleimide groups. This resin composition adheres extremely well to metals with a low dielectric constant and low dielectric dissipation factor, and demonstrates very little scattering of the resin during operational processes like punching or cutting. By using laminates or laminates for circuits that employ this resin composition, electrical signals can be propagated more quickly, enabling signals to be processed at faster speeds. In addition, the present invention can be applied to the formation of miniaturized circuit wiring, and is suitably employed in electronic devices employed in the high frequency region, and, in particular, in electronic devices that must be made smaller and lighter in weight.

The invention discloses a method and a device for monitoring main insulation of three phases of cables under intersection and interconnection of metal protective layers on line, relates to a method and a device for monitoring the main insulation of the three phases of cables on line, and aims to solve the problem that the conventional method and the conventional device cannot be used for monitoring the insulation performance of the three phases of cables under intersection and interconnection of the metal protective layers on line. Current flowing through wire cores at two ends of each phase of cable is measured by using two current transformers; a difference value is calculated, so that a current value flowing through the main insulation of the cable is obtained; due to measurement for three phases of voltage by a voltage transformer, a dielectric loss factor of the main insulation of each phase of cable can be monitored on line; and therefore, the main insulation of the three phases of cables can be monitored on line. A plurality of paths of synchronous analog/digital conversion chips at two ends are controlled to perform synchronous sampling through a global positioning system (GPS) satellite synchronous signal, and calculation is performed in a computer, so that the main insulation of the three phases of cables under intersection and interconnection of the metal protective layers can be monitored on line. The method and the device are suitable for on-line monitoring of the insulation performance of the three phases of cables under intersection and interconnection of the metal protective layers.

A class of ceramic compositions according to the formula Pb_(1-z)M_z(Mn_1/3Sb_2/3)_x(Zr_yTi_1-y)_1-xO₃ where M is selected to be either Sr or Ba, x is selected to be between 0.01 and 0.1, y is selected to be between 0.35 and 0.55, and z is selected to be between 0.01 and 0.10. In some embodiments of the above composition, one or more dopants is added to the compositions. The dopant(s) may be selected from the group comprising: PbO, CeO₂, SnO₂, Sm₂O₃, TeO₂, MoO₃, Nb₂O₅, SiO₂, CuO, CdO, HfO₂, Pr₂O₃, and mixtures thereof. The dopants can be added to the ceramic composition in individual amounts ranging from 0.01 wt % to up to 5.0 wt %. The preferred ceramic compositions exhibit one or more of the following electromechanical properties: a relative dielectric constant (ε) of between 1200 and 2000, a mechanical quality factor (Q_m) of between 1500 and 2800; a piezoelectric strain constant (d₃₃) of between 250-450 pC/N, a dielectric loss factor (tan δ) of between 0.002-0.008 and a thickness electromechanical coupling coefficient (k_t) of between 0.45 and 0.7.

The invention discloses a preparation method of a polytetrafluoroethylene copper-clad plate. The preparation method comprises the following steps: 1, evenly mixing raw material ingredients of polytetrafluoroethylene powder, a lubricating agent, ceramic powder and short glass fiber and curing; 2, moulding pressing to prepare a preform; 3, calendering to obtain a raw substrate and then drying; 4, covering the two sides of the raw substrate by copper foils, sintering, maintaining pressure and then cooling to the room temperature to obtain the polytetrafluoroethylene copper-clad plate. The preparation method replaces a preparation mode applying PTFE dispersion liquid to coating and impregnating and avoids harm of toxic fluoride, nitric oxide and the like; a good filler dispersing effect, evenness in mixing and good dimensional stability of a product are achieved. By means of reasonable matching, the prepared PTFE copper-clad plate has different dielectric constants from 2.6 to 8.6 MHz, a dielectric loss factor is smaller than or equal to 0.003, the peel strength is greater than or equal to 1.7 kN/m, and overall performance can meet the use requirement. The preparation method disclosedby the invention has the advantages of simple technological process and ability in meeting the requirement of industrial batch product.