RU2282296C2 - Method for creating electrical isolation system - Google Patents

Abstract

FIELD: technology for creating construction of electrical isolation.

SUBSTANCE: closed volume, wherein electrical systems of magneto-hydrodynamic pumps are positioned, operating under conditions of high temperature effect and radiation flow, are filled with filling compound, composition of which includes organic-silicate components, is heated up to temperature, exceeding working temperature, with burning out and removal of organic component, and remaining part is baked to solid mass, fixing electrical isolation and system and providing wholeness and resistance to vibration loads during operation.

EFFECT: increased reliability of isolation due to stabilization of geometrical position of system.

Description

Magnetohydrodynamic pumps, providing electromagnetic force on a liquid metal, are widely used in various fields of technology, for example, in nuclear energy. Magnetohydrodynamic pumps used in tank versions of reactor plants are submersible. The mentioned pumps must be characterized by high operational reliability and the absence of forced cooling of the windings. Therefore, the used insulating materials must have good enough thermal conductivity to ensure the removal of heat released in the windings into the surrounding coolant, and also be resistant to temperature and radiation influences.

The reliable operation of magnetohydrodynamic pumps depends on many factors and, in particular, on the high-quality performance of the electrical insulation system. High operating temperatures of the windings, radiation exposure, vibration and shock loads acting on magnetohydrodynamic pumps can lead to abrasion, embrittlement, damage to insulation and, as a result, to interturn short circuit or breakdown on the casing and failure of the pump.

At present, insulation materials have been created that successfully operate under conditions of high temperatures and radiation exposure. These are ceramic materials based on silicon oxides, aluminum. These materials have high hardness, but at the same time quite fragile.

The disadvantage of these insulating materials is the low manufacturability when creating a turn and case insulation, easy damage during assembly, as well as difficulties during machining.

There is a method of creating inter-turn case insulation of coils by winding a high-heat-resistant mica core with preliminary and subsequent coating of an organosilicate composition (L. M. Bernshtein “Isolation of electrical machines for general industrial use.” Energia Publishing House, Moscow, 1971, p. 70, 133).

The connection of the windings of the coils with each other and the isolation of the joints is carried out similarly to the above method.

The disadvantage of this method is the possibility of damage to the insulation of the coils and their joints as a result of radiation exposure and mechanical abrasion of the insulation due to movements due to vibration.

The aim of the proposed method is to increase the reliability of the insulation system: stabilize the geometric position of the system in its original form after assembly and increase its reliability by creating additional ceramic insulation around.

To this end, a method is proposed for stabilizing the insulation system by filling the closed volume of the inductor with a compound containing ceramic and organic components, followed by heat treatment. The organic component is a binder and gives the compound a fluid state.

The closed volume of the inductor, which is in a vertical state (with assembled, insulated coils connected to each other), is evacuated through air vents, then a filling compound is fed under pressure, which fills all voids and gaps. After filling the volume of the inductor, the pressure is relieved and placed in an electric furnace for heat treatment, where the temperature is raised in steps of 50-70 ° C with exposure at each step for 2-3 hours to the temperature at which the volatility stops. After extraction from the furnace and cooling in air, the air vent is cut off, and the hole in the body is welded.

As a result of heat treatment, the organic component of the casting compound is burned out, the volatiles exit through the air vent, the remaining part is sintered and forms a solid mass that fills the entire residual free volume of the inductor, due to which the electrical system is fixed in its original state. In addition, the resulting ceramics do not interfere with the thermal expansion of the thin-walled shell of the working channel and the operation of the bellows expansion joint of the pump due to the lack of adhesion.

Thus, this method of creating an electrical insulation system allows you to ensure its initial geometric position, increase its electrical resistance and obtain a technical result: increasing the reliability of the electrical insulation system and, thereby, increasing the reliability of magnetodynamic pumps at high temperature and radiation influences.

Information sources.

1. L.M. Bernstein "Insulation of electrical machines for general industrial use." Energy Publishing House, Moscow, 1971, p. 70, 133.

Claims (1)

A method of creating a system of electrical insulation of windings of devices, for example, magnetohydrodynamic pumps operating under high temperature conditions and radiation flux, including winding the core of the coil and the joints between the coils of flexible tape and high-strength materials with the previous and subsequent coating of the core with a compound, characterized in that it is closed the volume of the assembled inductor is evacuated and filled under pressure with a casting compound containing organosilicate components, relieve pressure e, heated to a temperature exceeding the working temperature, burned and removed the organic component in the form of volatiles, and the remaining part was sintered into a solid mass, stabilizing the initial geometric position of the system and creating additional insulation.