Compact High-Voltage Source for Operation in Vacuum
Abstract Generated abstract
This paper describes a compact electrostatic high-voltage source intended for operation in deep vacuum, motivated by the need for reliable electrical supplies for studies and devices associated with space-flight conditions. The proposed generator replaces rotating mechanisms with an oscillating capacitor plate driven by an internal electromagnet, alternately charging the movable plate at a low potential and discharging it through a high-voltage contact to the load. By using vacuum as the insulating medium and eliminating rubbing and rotating parts, the design aims to reduce friction losses, avoid bearing and lubrication problems, and produce output voltages on the order of tens of kilovolts in a compact sealed device.
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COMPACT HIGH-VOLTAGE SOURCE FOR OPERATION IN VACUUM
A. P. Kononov, V. A. Lukutin, L. M. Leus, A. I. Naletov
(Presented by the scientific seminar of the Department of TOE)
In connection with the development and expansion of space flights in recent years, the study of various phenomena and processes occurring in vacuum has become increasingly widespread. One of the most important tasks is the creation of a compact, reliable, and safe high-voltage source of electrical energy operating in vacuum. All existing high-voltage sources, among which various types of electrostatic generators may be included, have a number of shortcomings. Even electrostatic generators operating in a compressed-gas medium are not free of these shortcomings, although they have become the most widespread at present. An analysis of all the negative aspects of existing high-voltage generators made it possible to develop a generator that has a number of advantages. Since a deep vacuum is used as the insulating medium, in such a high-voltage source friction losses are completely eliminated, owing to which the highest efficiency is achieved in such an electrostatic generator among all machines based on electromechanical energy conversion.
The proposed source is a device resembling a parallel-plate capacitor, with one of its plates fixed immovably and the other able to move freely. The oscillation of the second plate can be regulated within any limits. The moving plate is alternately charged and discharged; in this way, a voltage on the order of tens of kilovolts can be drawn from this source into the load.
In the manufacture of an electrostatic generator with a rotating rotor in vacuum, the greatest difficulty is the creation of special bearings ensuring normal operation of the generator. For continuous operation of such a generator, additional devices are required to supply lubricant to the bearings and to remove heat; otherwise the bearings will become strongly heated, and their service life will be very short. This was the reason for abandoning rotating parts in the proposed generator.
The features of the electrostatic generator described include the following:
- Absence of rubbing and rotating parts.
- Absence of external excitation sources.
An electromagnet installed inside the vacuum chamber is used as the motor.
In the generator, a change in capacitance is used to transfer a constant charge from the region of low potential to the region of high potential. The change in capacitance is carried out by means of the electromagnet selected—
of the vibration type. The movable plate is made in such a way that it can oscillate at a frequency close to the natural frequency of the vibration drive. The plates of the generator and the electric drive are located in a chamber in which a vacuum of the order of \((10^{-6} \div 10^{-7})\) mm Hg is created.
Fig. 1. 1 — movable plate, 2 — fixed plate, 3 — insulated section of the movable plate, 4 — metal spring of the movable plate, 5 — coil with an iron core, 6 — contact of the excitation source, 7 — high-voltage contact; \(L\) — e.m.f., \(R_{\mathrm{n}}\) — load resistance, \(U_{\mathrm{v}}\) — excitation voltage
The operating principle of this device is quite simple. When an electric current flows in the circuit of the coil (5), which is the vibration drive, the core of the latter attracts the spring (4). Together with the spring, the movable plate (1) is displaced until it connects with the excitation contact (6). At this moment both the charging of the movable plate (1) from the excitation source and the interruption of the electric circuit of the electromagnet coil (5) take place. Under the action of the spring (4), which is no longer attracted by the electromagnet, the movable plate moves to the high-voltage contact (7), where it gives up its charge to the load, now at a higher potential. The entire process is then repeated.
The magnitude of the voltage delivered to the load will be determined not only by the change in capacitance between the plates, but also by the electric strength of the medium in which they are placed. Therefore, the entire device described above is placed in a vacuum chamber made of glass in the form of a cylinder. Metal contacts are sealed into the walls of this cylinder for supplying power to the electromagnet, for feeding out the excitation voltage, and for feeding the high voltage to the load.