SU641516A1 - Evacuated variable capacitor - Google Patents

Description

I

This invention relates to the field of radio engineering.

A variable capacitance vacuum capacitor, used mainly for tuning oscillatory circuits of high-power radio transmitters and containing packages of stationary and movable cylindrical electrodes placed in an evacuated case, a mechanism for moving a package of moving plates placed inside the bellows, and current pickups connecting the packages with external leads. Such a capacitor at frequencies of ten megahertz has a limited permissible reactive power, which is limited by excessive heating of the dielectric shell in the region opposite the edge of the outer lining, leading to the destruction of the latter. In this connection, when capacitors are operated at the indicated frequencies, they limit the permissible high-frequency voltage to values much lower than the electrical strength of the interelectrode radial gaps, limit the operating frequency, or reduce both of these parameters.

This reduces the permissible reactive power of the capacitors.

The aim of the invention is to increase the permissible reactive power of vacuum variable capacitors.

To achieve this goal, in a vacuum capacitor of variable capacitance, The main body, packages of movable and stationary cylindrical electrodes, made step-wise and located coaxially, the mechanism for moving the electrodes, snlfon and. conclusions, each subsequent electrode of the corresponding package from the side of the housing wall is greater than the length of the previous one.

FIG. vacuum condenser shown; in fig. 2 is a graph of the dependence of the electrical strength of vacuum capacitors of variable capacitance at low frequency (about 50--60 Hz) voltage (curve I) and high frequency (about ten megahertz) voltage (curve P) to a function of the set capacitance value; in fig. 3 - distribution of the electric field intensity (E) in relative units along the length (e) of the dielectric shell; and the co-dispatcher — the rototype (Kp; iba I1) and the distribution of 15-field electric field (E) relative to the length (e) of the dielectric shell of the proposed vacuum capacitor (IV).

The variable-capacity vacuum capacitor contains overlays 1 and 2 of translucent and) electrode electrodes placed in an evacuated metal-bodied housing 3, mechanism 4 for moving a pack of semi-sliding plates placed inside ciiji: background 5, and a current collector 6 connecting package 1 fixed electrodes with external output 7. The role of the second current collection: ik connecting the package of 2 electrodes with external output 8 is performed by the bellows 5.

The outer electrodes 9 and 10 of the fixed and movable packages, respectively, are made with a reduced mutual overlap. The drive mechanism of the capacitor consists of an adjusting screw 11, resting on the bearing 12 and interacting with the screw thread 13, made in the rod I, connected to the package 2.

The capacitor works as follows.

When rotating 11 in the clockwise direction, the pins 14 with packet 2 fixed on it moves towards the external output 8. At the same time, proportionally reducing the overlap of the plates of packages 2 and 1 decreases - the capacitor capacitance. As part of external electrodes 9 and 10 of the capacitor pack with reduced overlap, they (these plates) come out of mutual overlap before the overlap plates. As the plates that have gone out of each other overlap, the distance between them increases, therefore Avoid the electric field

only 1) less current is less than the intensity of the electric field between the same plates, if they were not divorced. Since undiluted internal

The plates are located at a greater distance from the dielectric shell; they create in it a smaller electric field strength with the same applied voltage.

Before the intensity of the electric float created in the dielectric shell by the next pair of plates reaches a critical one, these plates will also be diluted due to their complementing with an overlap. Thus, the intensity of the electric field in the dielectric shell decreases, therefore, in order to obtain the same maximum permissible intensity of the electric field, a higher voltage must be applied to the capacitor.

Claims (1)

1. Buts V.P., Zheleznov M.T., Yuriiov M.M. Vacuum condensers. “Energia, P - 1971, p. 27--4b. .7 and about FIG. t t / ffaa, Kf C.fff Shchi 2 ((Tues. eZ)