RU1798747C - Device for checking direct current magnetic comparators - Google Patents

Abstract

Usage: the invention relates to electrical engineering and is intended for calibration of DC magnetic comparators. SUMMARY OF THE INVENTION: the device comprises an adjustable constant current source, a null indicator, a switch and an exemplary constant current comparator, including measuring and sectioned compensation windings, a constant current amplifier and an ampere-nonequilibrium converter, the output of which is connected to a constant current amplifier input, adjustable the DC source through the measuring winding of the reference comparator is connected to the terminals for connecting the measuring winding of the verified comparator and the DC output of the compensation winding sections of the reference comparator is connected to the corresponding output terminals of the switch, the first input terminal of which is connected to the first output of the DC amplifier, the second output terminal of the latter is connected to the first terminal for connecting the compensation winding of the verified DC comparator, a second input terminal of the switch is connected to a second terminal of a similar purpose. 1 ill. ate with

Description

The invention relates to electrical engineering and is intended for the technological verification (in the manufacturing process) of DC magnetic comparators used to measure high currents.

The aim of the present invention is to increase the accuracy of calibration of magnetic comparators, which consists in accurately determining the number of turns of the compensation winding of the verified comparators.

The drawing shows a block diagram of the proposed device for checking magnetic DC comparators.

The proposed device comprises an adjustable constant current source 1.

exemplary DC comparator 2, measuring 3 and compensation 4 windings, DC amplifier 5, transducer 6 for nonequilibrium windings windings 4 and 5, switch, zero indicator 8, terminals 9, 10 and 11, 12 - for connecting measurement 13 and compensation, respectively 14 windings of a calibrated comparator 1.5 DC. The output of the null-indicator 8 is connected to the output of the nonequilibrium converter 16 of the ampere-turns of the windings 13 and 14 of the verified comparator 15.

The findings of an adjustable DC source 1, one directly, and the other through the measuring winding 3 approach | Yu

00

2

Xi

connected respectively to the terminals 9 and 10 for connecting the measuring winding 13 of the verified comparator 15. The outputs of the sections of the compensation winding 4 are connected to the corresponding output terminals of the switch 7. The first input terminal of the switch 7 is connected to the first output terminal of the DC amplifier 5, the second output terminal of which and the second input terminal of the switch 7 are connected respectively to the terminals 11 and 12 for connecting the compensation coil 14 of the verified comparator 15.

The switch 7 in the simplest case can be made on the basis of commercially available, for example, key switches. The implementation of other elements is disclosed in 2.

The device operates as follows. :

The current 1i, flowing through the measuring windings 3 and 13 of model 2 and verified by 15 comparators, creates in each of the converters 6 and 16 of the ampere-coil imbalance the magnetizing force (NS) FHWH (for simplicity we assume that the windings 3 and 13 are single-turn , i.e. WH - T vit.). Under the influence of N.S. at the outputs of converters b and 16 of the imbalance of the ampere-turns, the mismatch voltages appear, which are respectively supplied to the input of the constant-current amplifier 5 and to the zero indicator 8 ..:; . ;

Under the action of the mismatch voltage supplied to the input of the DC amplifier 5, an IK current is generated at the era output, which is supplied through the compensation winding 14 and the switch 7 to the sections of the compensation winding 4. Flowed through the included switches 7 of the section of the compensation winding 4, the current to creates in the transducer 6 nonequilibrium NS: GkMk, directed towards NS 1nMn, the Reference comparator is a closed system of automatic regulation of the next type, the action of which is aimed at maintaining the balance of the GNUU and ijcWk asherwitches, here and above the WR-number of switched-on turns of the compensation winding 4.;

In steady state, the state indicated above the contour is automatically controlled by the ratio;

IHWH-IKWK AtWi, where E) L / 1 is the effective mismatch s of the autoregulation loop in static mode. The value of current k is equal to.

. IK (| HWH-. AIWO / WK (1)

As already noted above, the current k flows along the compensation winding 14, the number of turns of which is equal to WKn. In this case, an N.s. directed towards ns 1nMn, (recall that the SS IHWH is created in the nonequilibrium transducer 16 by the measuring winding 13 with current n). Resulting N.S. (2IW) acting on

the nonequilibrium transducer 16 is equal to

IIW IHWH - IKW

kp

fifteen

or, taking into account the relation (1)

2lW lHWH- (lHWH-. AlWi) WKn / WK. (2)

Using switch 7, the operator can turn on WKO turns of compensation

windings 4, with WKO WKn. In this case, the resulting nonequilibrium transducer 16 is affected by the result: 2 IW D IWi. Co, respectively, the null indicator gives the deviation YES, the magnitude of which is proportional, and the sign is determined by Sign D IWi.

The solution to the problem of checking the comparator consists in this case in precisely determining the number of turns of the MCP of its compensation winding 14. As can be seen from the description of the operation of the proposed device, this device provides such an opportunity. For its implementation, it is necessary to fix the state of WKO -WKn, after which the numerical value of WKO is read from the display elements of the switch 7 and, thus, the number of turns of WKn becomes accurately known.

However, as follows from the description of the work

device, with WKo WKn there is a deviation of the YES of the null indicator from its zero position. The presence of this deviation makes it difficult to fix the state in which WKO WKn. In order to reliably record the state of WKO WKn, it is necessary that the current value satisfy the condition. ...

fifty

n D IW, WKnH / WH,

(3)

5

WKHH is an unnamed number equal to the nominal number of turns of the compensation winding 14 of the verified comparator 15. Condition (3) is a criterion for selecting a current value of 1c.

The verification process is carried out as follows (only operational operations are considered here, it is believed that all preparatory operations have been completed previously). The switch 7 is set in such a position that the deviation of the zero indicator is minimal and equal to YES (first operation). By the indication elements of the switch 7, the number of turned-on turns of the WKO winding 4 is registered. Then, the switch 7 makes a change in the number of turned-on turns of the winding 4 by one turn in the direction of decreasing (second. Operation). In this case, the deviation of the zero indicator 8 will be AI, for example, in the region of negative values. After that, the switch 7 changes the number of turned-on turns of the winding 4 by one turn in the direction of increase in comparison. value with the registered WKO value (third operation). In this case, the deviation of the null indicator will be AZ in the region of positive values, with I At I I A2 1. Note the following. If during sampling of the current value the condition (3) was observed, then I I I YES I,

If in a particular verification case everything happens in exact accordance with the verification process described above, then the WKo value recorded after the first operation corresponds to the WKO Wxn state. This means that the number of turns of the MCP is precisely determined.

Thus, the proposed device provides an accurate measurement of the conversion coefficient of the verified comparator, i.e. increasing the accuracy of verification.

Form l a is b re ten and

A device for checking magnetic DC comparators, comprising an adjustable DC source,

exemplary DC comparator containing measuring and compensation windings, DC amplifier, nonequilibrium converter

ampere-turns of the measuring and compensation windings of an exemplary comparator, the output of which is connected to the input of a DC amplifier, an imbalance converter of the ampere-turns of the measuring and

compensation windings of the verified comparator, an adjustable DC source through the measuring winding of the reference DC comparator is connected to the terminals for connecting the measuring winding of the verified DC comparator, distinguishing it so that, in order to increase the accuracy of verification, a null indicator and a switch are introduced, and a compensation winding

the exemplary comparator is made in the form of separate sections with a different number of turns, the conclusions of the sections are connected to the corresponding output terminals of the switch, the first input terminal of which is connected to

the first output terminal of the DC amplifier, the second output terminal of which is connected to the first terminal for connecting the compensation winding of the calibrated DC comparator, the second input terminal of the switch, the output of the ampere-nonequilibrium converter, is connected to the second terminal for connecting the compensation winding of the verified DC comparator The measuring and compensation windings of the verified DC comparator are connected to the input of the zero indicator.