DE576082C - Method of manufacturing an electrical capacitor with laminated paper plate dielectric baked in mechanical or hydraulic presses - Google Patents

Description

Method of manufacturing an electrical capacitor with in mechanical or hydraulic press baked hard paper board dielectric When using of hard paper sheet material for high voltage capacitors was the difficulty that the capacitors had too short a service life.

In order to obtain particularly reliable capacitors, a hard paper was used used, which has a dielectric strength that is as high as possible in the case of short-term testing showed because of the dielectrics that have been tried and tested in low and medium voltage It was believed that a very high test voltage when fresh was also a guarantee for a long service life of the material.

With other dielectrics, this aspect has also proven itself, but it has failed with hard paper plates, so that so far hard paper plate capacitors had to be built for high voltages with great material costs and as a result have introduced little into practice.

In hard paper plate high voltage capacitors is namely for the Service life not the initial test voltage, but the loss angle is decisive.

With other dielectrics, e.g. B. the oil-soaked paper of cables, in the case of the paraffinized paper capacitors (so-called post capacitors), however, existed even earlier the endeavor to reduce the loss angle as much as possible; also was it is already known to use a sheet-shaped dielectric to reduce the size of the dielectric To dry up the loss if possible. That was taken for granted, because with these Materials with decreasing loss angle the dielectric strength increases, as mentioned above, was regarded as a measure of goodness.

But while with hard paper capacitors the relationship between Heating and loss angle of course follow the same law as at other dielectrics, the dielectric strength depends on the Loss angle other laws.

The breakdown voltage has a at a certain loss angle Shows the maximum when the loss angle is reduced beyond the optimum Dielectric strength no longer increases, but on the contrary a considerable one Acceptance.

The area behind the optimum of the loss angle was therefore due to the lower dielectric strength so far avoided.

However, the warming curve also falls after it is exceeded the optimum of the loss angle further; but that is irrelevant since the heat build-up does not play a decisive role here and hard paper capacitors at most extremely high frequencies perish through overheating during their lifespan in the case of technical alternating voltage and in the case of direct voltage, this is not due to the heating is limited.

The invention therefore relates to a method for producing an electrical capacitor with hardening paper plate dielectric baked in mechanical or hydraulic presses; According to the invention, the drying of the dielectric is driven so far that the loss factor of the dielectric tg 8, measured at room temperature, 50 per./sec. and in the case of a dielectric stress on the dielectric below the ionization kink, it is not greater than o, oz6.

The limit of the optimal dielectric strength is therefore conscious in the realization has been exceeded that dielectric strength and service life for hard paper capacitors not at all, as previously assumed, corresponding Concepts are that it is even possible by taking the action further ultimately lead to a reduction in dielectric strength, a considerable one To achieve an increase in the service life, and that if, for. B. in the case of follow-up This thought the dielectric strength reduced to half of the optimum the lifespan is practically unlimited.

A capacitor with a reduced breakdown voltage was therefore deliberately made manufactured in order to increase the service life, which is more important for the operation achieve.

In a further advantageous embodiment according to the method The capacitor manufactured according to the invention is the one equipped with this dielectric Condenser permanently in fats, liquid or solid oils or impermeable to moisture Casting or molding compounds embedded. This measure also applies to capacitors with hygroscopic dielectric or with those where the embedding material itself forms part of the dielectric, known for hard paper plate capacitors but it is new and its success could not be foreseen, as hard paper board material is considered to be unhygroscopic and, under ordinary circumstances, indeed a sufficient one Has resistance to water absorption.

Claims (3)

CLAIMS: i. Method of manufacturing an electrical capacitor with hard paper plate dielectric baked in mechanical or hydraulic presses, characterized in that the drying of the dielectric has taken this far is that the loss factor of the dielectric tg Ö, measured at room temperature, 5 persons / sec. and in the case of a dielectric stress on the dielectric below of the ionization kink is not greater than o, oa6. 2. According to the method according to claim z manufactured electrical capacitor. 3. Capacitor according to claim 2, characterized by embedding in moisture-impermeable agents such as fats, oils, Vergaß or Molding compounds.