CS251259B1 - Apparatus for demonstrating convection currents - Google Patents

Abstract

The device is intended for demonstration of convection currents. The device consists of a disk of insulator (first variant) or of conductor (second variant), which is set into rapid rotation by an electric motor, while the disk is provided with a notch guided in the radial direction. Indication (sensing) of convection currents is provided by an electromagnetic sensor, which is slidably placed against the front surface of the rotating disk. The device can be used for orienting research of the structure of rotating disks.

Description

The present invention relates to an apparatus for demonstrating convective currents.

OF

The prior art solutions solve the problem of indicating convection currents by a rotating insulating disc having a conductive coating on its periphery or by means of a rotating plate capacitor which rotates as a whole. All of these devices need an auxiliary power supply to operate on the rotating plates to function. The excited magnetic field is very small, so a very sensitive device for indicating convective currents is needed.

The purpose of the invention is to remedy the above mentioned drawback.

This object has been solved by providing an apparatus for demonstrating convective currents, the principle being that an electromagnetic sensor is provided opposite the rotating disc of insulating material or conductive material, which serves to indicate the convective currents, the disc being cut in the radial direction.

The main advantages of the arrangement according to the invention are that the need for an auxiliary voltage source is eliminated and the indication of convection currents is simple to manufacture.

1 is a schematic representation of the assembly of the apparatus of the present invention; and FIG.

The apparatus consists of an electric motor 2 with bearings with an extended axis of the electric motor 2 'at the end of which is removably mounted the examined disc 2 with radial notch 2, which together with the electromagnetic sensor 2 are fixed to the base.

The transducer 2 is adapted to be movable in two directions towards the disc 2 against whose face it lies. A sensor coil 2 ^te wound wire of diameter 0.05 mm (20 kilohms). The required measuring instruments are connected directly to the sensor coil terminals 2 ·

In a first variant, an insulating disc 6 is used, which is charged by friction of the hair during rotation. The charge is unevenly distributed on the surface of the disc 2 'so that as it moves around the sensor 2, its size changes and thus the magnitude of the resulting magnetic field changes, to which the sensor 2 responds by induced alternating voltage of a completely irregular frequency.

The second variant is based on the inertia resistance of electrons to mechanical motion. In a rotating metal disc 2 provided with a radial notch, free electrons accumulate on the leading edge of the notch due to the inertia resistance.

On the opposite edge of the notch, a lack of electrons creates a positive charge. The rotation of the disc 2 causes the movement of both of these charges to create a weak magnetic field in the surrounding area of the indentation, which, by passing the indentation around the sensor 2, causes a current impact of a completely definable nature.

The construction of the apparatus according to the invention makes it possible to perform an approximate measurement of the structure of the individual disks while substantially reducing production costs.

Claims (1)

SUBJECT OF THE INVENTION Apparatus for demonstrating convection currents consisting of an elongated shaft electric motor and an electromagnetic sensor, wherein a disc is removably mounted on the elongated shaft, characterized in that the disc (2) is radially indented, the electromagnetic sensor (3) being positioned against the disc face 2) and is movable in two directions.