SU74059A1 - Device for measuring the loss tangent - Google Patents

Description

The subject of the invention is a device for measuring the loss tangent angle based on the phenomenon of electrical hysteresis. Thus, if, in the sphere of action of a rotating electric floor, to suspend some object of insulating material, then this object will rotate around its axis by a certain angle from the initial position under the action of the floor.

A feature of the proposed device is the use of an electrostatic measuring device in it, consisting of the following parts:

1) four fixed plates, placed in a circle AND connected to the terminals connected in series of the reference and test capacitors;

2) a movable core made of insulating material with a pointer mounted on its axis;

3) connected in series with the reference capacitor of change. There is resistance, which is used for counting the loss tangent at the position of the slider corresponding to the zero position of the decree, the instrument bodies.

A schematic diagram of the proposal, my device shown in the drawing.

Here C l- is the reference capacitor (usually mica-per To 200–300 μmkf);

R - variable graphite res. a few meg megashes; J, 2,3 and 4-fixed copper plates located around the ring.

Inside the ring on a thin pendant or straggle, measles A is marked with a pointer mounted on it moving along the scale with divisions.

The device is enclosed in aluminum, from which insulated terminals Ki and Kz come out and the earth contact Kz.

The test capacitor Cx is connected to the Kz terminal. The high voltage insulators required for testing high voltage insulators are cos. given by step-up transformer Tr.

When connecting to the alternating voltage circuit and derived resistance R, the entire voltage of the transformer is distributed between. do capacitors Cyv Cx, and the voltage {7, v will be connected to the plates 2 and, and (/ x - to the plates / and 5.

Since the losses in the tested capacitor Cx are greater than in the reference capacitor Cdg, the voltages f / l will be shifted by one

153

relative to the other in phase. Due to this shift, a rotating electric field is created, which turns the measles with the pointer arrow. Entering the coping /, achieve setting the pointer to the zero position, which is the case when the condition of the equilibrium scheme is observed:

,

where w is the angular frequency of the voltage.

At constant values and Su, their product is a constant value, and the final equation for the instrument takes the form

,

where A is a constant of the device itself.

In practice, limb handles of variable resistance are usually graded in tgo.

The advantages of the scheme are the simplicity of the design, the presence of only one like handle and the relatively small size and weight.

Object of the invention A device for measuring the loss tangent, characterized in that it employs an electrostatic measuring device composed of: four fixed plates arranged in a circle and connected in pairs to the terminals of the reference and test capacitors connected in series; a moving core with a pointer mounted on its axis, and an adjustable resistance connected in series with the reference capacitor is used to measure the tangent. CA loss angle at the position of the engine, corresponding to the zero position of the instrument pointer.

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