DE717447C - Method for achieving a loop-free temperature profile of the capacitance of electrical capacitors - Google Patents

Description

Process for achieving a loop-free temperature curve the capacitance of electrical capacitors All plastics that turn into insulating films can be processed, as far as their electrical values allow, to the structure used by electrical capacitors. Above all are the descendants the vinyl group, especially polystyrene films; used to build capacitors where it is possible especially when using stretched polystyrene tape was to use very specific manufacturing processes, especially for the plastics developed to allow the manufacture of capacitors with surprisingly good values.

Among other things, it is z. B. known that made with stretched synthetic film To expose winding capacitors to a more or less long period of heating in order to thereby an extension, d. i. to achieve a contraction of the insulating hand, wherein the air is driven out of the coil and when using the appropriate Temperatures even a welding of the freely lying edge parts of the Insulating foils occurs. This method achieves capacitors with very constant capacitance.

It turned out, however, that all the capacitors with a stretched one polymeric material as a dielectric with increasing and decreasing temperature have loop-free temperature response of the capacitance, d. H. a precisely matched one Condenser that heats up to its highest operating temperature and then again is cooled, shows at the starting temperature one of the . @ nfangstver t different capacity value. The increase in capacity with normal get @ icl; elten and balanced capacities is z. B. after heating to 60 ° C up to .`3 @ 'Q.

However, even with these relatively small errors, there is one very big disadvantage if the Kapazitits @ vert after a random, but The fact that the capacitor body does not warm up during operation changes. The effort In manufacturing, the aim was a loop-free temperature curve of the capacity to achieve, d. h to make the temperature curve reversible without misregistration.

In order to achieve this with capacitors of the type described, according to the invention, the dielectric material at a temperature a few degrees higher than the use temperature for a significantly longer time than for the dehulling required exposed and then slowly cooled to room temperature, whereby it is possible that: dielectric material both before and after it Processing to: subject a condenser to heating.

It has already become known, stretched art foils are heated to undergo to the film in a partially stretched or fully de-stretched Attributed to the state. The heat exposure time required for this process However, it is not sufficient to ensure a loop-free temperature curve of the capacitance to obtain; rather, even after the partial stretching process has ended, the Different temperatures demand different times, even longer exposure to temperature can also be achieved by the present invention to achieve the effect described. A capacitor that z. B. removed at 8o C. -will takes a time of one hour for this, after which the dehulling process z. B. for a normal round nickel capacitor with expanded polystyrene dielectric has practically ended and no further changes in capacity occur.

However, this capacitor is not yet free of loops in its temperature response. Only when the heat exposure is extended to about hours is the temperature too a-Lurgang reversible, d. H. the marked treatment of the dielectric material, which can be referred to as tempering results in capacitors whose capacitance is up to a clear function of the temperature for the maximum permissible operating temperature is.

The reason for this behavior may be to look for a lot of light in that due to the effect of heat an excessive state of slackness, especially the on The surface of more equitable molecules is eliminated, creating a state of equilibrium is achieved at which molecular stimuli, especially the low molecular weight Shares, are stopped, so that, as it were, from a reorientation of the molecules spoken «- can earth.

The subsequent slow cooling has the purpose of quenching prevent the dielectric material from suddenly dropping in temperature, as a result of which, as was clearly established, internal material stresses occur again that can change the values already achieved.

The treatment of the dielectric material prior to its processing to the capacitor has the other invaluable advantage that on the winding machine z. B. by means of a connected Mefabrücke directly adjusted to the capacitance uert wound «, since there is no post-treatment, neither in the form of heat treatment still in the form of impregnation o. The like., More takes place, so that the on the machine produced value corresponds to the final value of the finished capacitor.

This is an advantage especially with those who have very good electrical power Capacitors with properties with polymeric material as dielectric is very important. since there is as good a waste in production as it is not.

This process also allows the manufacture of combined capacitors to, in which several partial capacities are contained in one winding and of which each and every one can be manufactured with precisely prescribed values, which has been the case up to now as a result of the unforeseeable changes in the subsequent heat treatment not possible - rare.

A treatment of the dielectric material can be used for the annealing in any heat hammer, z. B. in an oven, or a treatment can be used in the high-frequency field, the latter method having the advantage the even warmth and thus an even development of values. It is also possible to obtain the ured result by treating the dielectric to achieve with ultrasonic waves.

Claims (3)

PATENT CLAIMS: i. A method for achieving a temperature curve free from shocks in the capacitance of electrical capacitors finite polymeric material as @iwlclctrikurr., Characterized in that the dielectric material before or preferably after its processing into capacitors is at a temperature a few degrees higher than the service temperature for a significantly longer time than is exposed for dehulling necessary, after which slow cooling down to room temperature takes place anyway. 2. The method according to claim i, characterized in that that the heating of the dielectric material to the: required temperature is achieved by exposure to a high frequency field. 3. The method according to claim r, characterized in that the heating of the dielectric material to the required temperature is achieved by the action of L'ltrasonic levels. Process for the production of electrical capacitors with on the winding machine balanced capacitance values with a dielectric made of polymer material, thereby characterized in that the dielectric is a pretreated according to claim 1, 2 or 3 Material is used.