SU1677672A1 - Method and device for tolerance testing of insulation resistance - Google Patents

Abstract

The invention relates to a control and measuring technique. The purpose of the invention — an increase in the reliability of the control — is achieved by changing the magnitude of the measurement voltage. The device for implementing the method further comprises a measuring voltage setting unit 7, with which the measurement voltage is adjusted, which leads to a decrease in the total number of commutations. The device also contains a measuring voltage source 1, terminals 2, a current-to-voltage converter 3, a unit 4 for setting the equivalent resistance, a threshold unit 5, an indication circuit 6 2 cf ff, 1 slug.

Description

about

Xi

Vj

Os VI

GO

This invention relates to a measurement technique and can be used to control the insulation resistance,

The purpose of the invention is to increase the reliability of the controls.

The drawing shows a block diagram of the device tolerance insulation insulation for the implementation of the method.

The device contains a measuring voltage source 1, terminals 2 for connecting a cable, a current-voltage converter 3, an equivalent resistance setting unit 4, a threshold device 5, an indication circuit 6, a measuring voltage setting unit 7. At the same time, the source 1 of the measuring voltage is connected to one of the terminals 2 for connecting the cable, and the second terminal is connected to the input of the converter 3, the current is the voltage whose output is connected to the input of the threshold device 5, and the output of the latter to circuit 6 indications. The output of the equivalent resistance unit 4 is connected to the second input of the current-to-voltage converter. The first output of the measuring voltage installation unit 7 is connected to the measurement voltage source 1, and the second to the input of the equivalent resistance installation unit 4.

The device works as follows.

The current through the insulation resistance of the cable connected to the terminals 2 arising under the action of the output measuring voltage is converted by means of the current-voltage converter 3. The output voltage of the converter 3 current - voltage is determined in accordance with the formula

 Cism

RSKB L Nism

D UM3M omch

Cack 7: Cack. ()

1Ч13М

where 1) meas - measuring voltage from the output of measuring voltage source;

Nizm - insulation resistance of the connected cable;

Neqv is the equivalent resistance of the generator current - voltage.

With the help of the threshold device 5, the voltage from the output of the converter 3, the current - voltage is compared with the threshold voltage, the value of which is determined in accordance with the formula:

I | UHSM D - n UHJM NecV, 0. Unop ---- KPOR - PW

R

pore

and

pore

where 11ism is the output voltage of the measuring voltage source;

Yaekv - equivalent resistance;

Unop is the threshold voltage.

If the value of the insulation resistance is equal to the value of the preset norm, then it follows from formula (2) that

- R

 -

normal - Uism Oh,,

(3)

R

where and the ratio is proportional to unop

onality

By means of the measuring voltage setting unit 7, the value of the output voltage of the source 1 of the measuring voltage is set numerically equal to the value of the norm. With the help of the unit 4 for setting the equivalent resistance, controlled by the unit 7 for setting the measuring voltage, the value of the coefficient o is set. depending on the range of values of the norm in accordance with formula (3).

After comparing the voltage from the output of the converter 3 current - voltage with the threshold voltage, the monitoring results are indicated by means of the indication circuit 6.

The value of the insulation resistance rate is determined by calculation and lies in a wide range, and the resistance control should be performed with an accuracy of no worse than 10%, which requires a large number of control points. This solution allows to increase the number of control points to 540, which is more than an order of magnitude greater than the capabilities of existing instruments.

Claims (2)

1. The method of tolerance control of the insulation resistance, which consists in connecting the cable to the input terminals of the device, setting the value of the resistance standard by setting the value of the equivalent resistance, supplying the measuring voltage, time delay, characterized in that, in order to increase the reliability of the control, when setting the value the impedance norms, after setting the value of the equivalent impedance, set the measuring voltage value. 2. A device for tolerance control of insulation resistance according to claim 1. containing measuring voltage source, first and second terminals, voltage converter, equivalent resistance installation block, threshold device, display circuit, output voltage of measuring voltage source connected to the first terminal, second terminal connected to the first input of the current converter - voltage, second the input of which is connected to the output of the unit of installation of equivalent resistance, and the output in series Connected to a threshold unit and display circuit, characterized in that, in order to increase the reliability of the control, a unit for installing a measuring voltage is introduced into it, the first output of which is connected to the input of a source of measuring voltage, and the second output is connected to an input of a unit of equivalent resistance.