SU48877A1 - Automatic adjustment device - Google Patents

Description

The present invention relates to AC rectifiers with controlled grids, the so-called thyratron, and aims to align the external characteristics of such rectifiers when they are equipped with a smoothing filter containing, in particular, an output capacitor.

As is well known, in such devices at low loads the capacitor does not have time to discharge, as a result of which the voltage becomes high (see, for example, p. 312 in A. M. Kugusheva's book "Electric Power Supply of Radio Equipment KUBU Ch, 1935). For radio transmitters powered by such rectifiers, a sharp increase in voltage with decreasing load is detrimental.

As one of the measures to combat this increase in voltage. The discharge is to leave a constant ballast load at which the current / o does not fall below the value of Hoh, after which a sharp increase in voltage occurs. In particular, when powering wireless telegraph transmitters, the current when the key is pressed must be equal to or somewhat greater than the current / hedgehog. A particularly sharp increase in voltage is obtained with large

grid voltage cutoff angles in controlled rectifiers. The value of the current dd can be calculated

E according to the formula / o.r--, in which t-

the number of phases, to-circular frequency, and L-coefficient of inductance of the filter.

From this formula it follows that the resistance value for a constant ballast load can be calculated using the formula RX. In many cases of practice, the magnitude of the ballast load, usually a nonbolt with a reduced voltage, with an increase in the voltage of the rectifier reaches large values.

According to the invention, this disadvantage can be eliminated by automatically adjusting the magnitude of the ballast resistance, which is the kenotron, properly connected.

The accompanying drawing shows a schematic diagram of a device according to the invention. Here, the conductivity of the kenotron 1 depends on the cathode filament current, while the value of the filament current depends on the inductive resistance 3, which is located in the filament circuit and has an additional constant

magnetization current main load. The core of this throttle carries the third winding 4, through which direct current flows from a separate rectifier or other source (battery). When the main load current is small, the inductive resistance of the Drossel 3 is very small and the maximum current passes through the cathode of the kenotron, as a result of which the average value of its internal resistance is small. When the main load is switched on, the core of the throttle 3 receives an additional magnetization of the opposite sign compared to the current passing through its winding 4, as a result of which the inductance of the throttle increases, the heating current decreases, the average value of the internal resistance of the kenotron increases and the ballast load decreases.

The subject matter of the invention.

A device for automatic adjustment of ballast resistance, which serves to maintain the rectified voltage in a thyratron rectifier, characterized in that, in order to increase the current of the main load, the value of the ballast resistance increases, as the ballast resistance, kenotron 1 is used, Transformer 2 and choke 3 are connected to the filament circuit 6, whose resistance increases with increasing current of the main current; due to the presence of a constant magnetization from a source connected to the coil 4, the current of which has the opposite direction compared to the main load current.

1n