SU62274A1 - Vacuum discharge valve test device - Google Patents

Description

A device is described for testing various discharge valves, for example, gas torches, thyratrons, ignitrons, mercury arc rectifiers, kenotrons, and others.

This device is of particular importance when testing high-pressure gas-discharge valves designed for high anode current values.

The device provides a significant reduction in power consumed during the test and a reduction in the number of power sources.

As is known, a full valve operating in a rectifier device has two modes: direct mode and reverse voltage mode. The direct voltage mode corresponds to the conductive part of the period. At this time, a direct anode current flows through the valve, and the voltage at the valve is relatively small (on the order of 10-20 V for gas discharge devices with a heated cathode). In the valve itself, power is released, equal to P - Vgiada

where Va is the voltage across the valve in the conductive part of the period, ia is the anode current, and co.

In this case, the valve is heated, which usually leads to a decrease in its electrical strength under reverse voltage.

Reverse voltage mode corresponds to the non-conductive part of the period. At this time, a reverse voltage is applied to the valve, directed by the minus to the anode. In this case, in gas discharge valves, a so-called reverse current usually flows, the magnitude of which determines the electrical strength of the valve. If the valve is not strong enough, then at reverse voltage it breaks through and loses its valve properties.

In the second mode, the power allocated to the valve is negligible.

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No. 62274-2 -

Testing the valve requires bulky equipment and a source of high-power electrical energy.

Previously, it was proposed to test rectifiers under conditions of equivalent, from the point of view, operating conditions in which the rectifier was placed. An example of devices for such tests is a synchronous mechanical switch with rotating parts and a device proposed by the author for which the author was issued. St. No. 32057.

Basically auth. St. No. 32057 proposed a device for testing rectifiers using two different sources of voltage of different polarity, alternately replacing each other. The triode source connected to the anode of the test rectifier by the cathode is connected to the low-voltage source circuit, and a diode that is cathode-oriented to the rectifier cathode is connected to the high-voltage source circuit, and a bias voltage is applied to the triode grid circuit.

The present invention is a development of the invention in the main author. St. No. 32057.

In the proposed device, a gas discharge valve with controlled ignition timing is used as a valve in a low voltage circuit, and a similar gas discharge valve or a valve with electrostatic control is used in a high voltage circuit.

For the supply of high and low voltage circuits, DC sources can be used.

The power source of the low voltage circuit can be a periodically charged capacitor.

These innovations greatly enhance the effectiveness of the invention and expand its scope.

The invention is explained in FIG. 1 and 2.

FIG. 1 is a schematic diagram of the proposed device.

The test valve 8 is alternately intermittently supplied with voltage through transformers 2 and 10. Transformers / and 5 with regulators (for example, potential-regulators) can be taken as such sources.

Phase regulators, for example, phase regulator 17, can be included in the primary circuits of these transformers.

Transformer 2 - low voltage, for high power. Its voltage is chosen so as to sufficiently close the ignition thresholds of valves 4 and 8 and to create sufficient heating of the test valve 8.

Transformer 10 is designed for high reverse voltage and low reverse current. As such a transformer it is convenient to use low-power transformers used in X-ray installations.

A direct voltage is supplied through a gas-discharge valve 4 with a controllable gas ignition moment, designed for the full forward current of the test valve 5. It is convenient to take an ignitron or a thyratron as such a valve. The use of ignitron gives a number of advantages over other types of gas-discharge valves, namely, the ability to obtain an infinitely large anodic current, the cathode's ability to withstand very large overloads, clarity in controlling the moment of ignition of the gas discharge, a small internal voltage drop and small internal losses.

The igniter is ignited using a special auxiliary circuit consisting of a DC source 7 charging a capacitor 6 discharged by a gas discharge valve 5 with a cold or heated cathode.

The direct current flowing through the test valve 5 can be measured using an ammeter 3.

High reverse voltage is applied through the electronic vein, type 14 (electronic lamp). The gas-discharge valve can also be used as the valve 14, but the electronic valve here will be preferable, since it has a greater electrical strength under reverse voltage.

The electronic valves can use an uncontrolled valve, i.e., a diode, or a valve with smooth electrostatic control, i.e., equipped with a control electrode - control Grid (triode, tetrode, pentode, etc.).

The use of a controllable valve allows control of the moment when the reverse voltage is applied to the test valve. In this case, a pause of adjustable duration can be arranged between the moment of the end of the flow of the direct anode current through the valve under test and the moment of application of the reverse voltage. This possibility is of great importance from the point of view of studying the deionization processes in the test valve.

By using a gas discharge valve with a controllable gas discharge ignition torque in a high voltage circuit, it is possible to set the desired return voltage to the desired jumps; this may be important for special studies.

The reverse current of the test valve can be measured using a measuring device (milliammeter or microammeter) 15.

To measure the amplitude of the reverse voltage, an auxiliary circuit can be used, consisting of an electronic valve 13, a capacitor 12 and an electrostatic voltmeter 11 connected in parallel with the capacitor 12.

FIG. 2 shows the curves characterizing the operation of the test valve in one period of alternating current feeding the device. The solid line shows the voltage curve between the anode and the cathode of the test valve, and the dotted line shows the direct anode current curve. The test valve with the help of the device proposed is put under conditions equivalent to the working one, but with an incomparably lower power consumption, since the useful load (external rectifier circuit) is practically absent here.

A small resistance (5) is adjustable.

Some variations of the present invention are possible. In particular, a potential varying in time according to a law can be applied to the control electrode (grid) of the high voltage circuit valve 14. Due to this, the shape of the reverse voltage curve may change. It is possible to create such conditions, when at one or another pulse width the reverse voltage curve has a steep decline.

For this purpose, the control grid of the valve 14 is energized from a peak transformer, a relaxation generator, etc.

In another embodiment, a DC source 16 can be used as a high voltage source 0; the voltage from the latter is periodically fed through the controlled leggil 14, and

X 62274