RU1791863C - D c instrument transformer - Google Patents

Abstract

Usage: in the field of measuring technology. SUBSTANCE: transformer contains a ferromagnetic core T, a primary winding 2 with a measured current and a secondary winding 3 connected to an alternating voltage source 4. A current sensor 5 is installed in the winding 3 circuit. Identical amplifier-decoupling transformers 6 and 7 are connected to the current sensor, and two oppositely connected diodes 8 and 9 are included in the secondary windings of them. The capacitors 10 and 11 are designed for smoothing. Resistors 12, 13 and 14 constitute a unit for subtracting the amplitude values of the half-waves of the secondary current. 3 ill.

Description

The invention relates to the field of measurement technology and can be used to measure direct currents in high and low voltage DC circuits.

Direct current direct current ammeters or by shunts are known.

Their disadvantage is the difficulty of freezing constant currents, as well as currents in dc dc circuits.

These drawbacks are eliminated in the closest direct current measuring transformer to the invention, comprising a ferromagnetic core with a primary winding and a secondary winding having inputs for connecting to an AC power source, a smoothing filter.

The purpose of the invention is to simplify the design of a transformer.

This goal is achieved in that the direct current measuring transformer containing a ferromagnetic core with a primary winding and a secondary winding having inputs for connecting to an alternating current source, a smoothing filter, has a current sensor, two identical amplifying-isolating transformers, two opposite diodes included, an additional smoothing filter, a unit for subtracting the amplitude values of half-waves of the secondary current, and an indicator whose input is connected to the output of the unit subtracting the signal at the output of the smoothing filter, the inputs of which are connected through respective diodes counterfield molecular weight to the secondary amplifying and isolation transformer, the primary windings of which are connected to the output of the sensor.

Figure 1 shows a circuit diagram of a transformer; Fig. 2 is a graph illustrating the operation of the circuit; in Fig.Z - the formation of a useful signal on the indicator.

Here, the closed ferromagnetic core 1 comprises a primary winding 2 with a measured current AND and a secondary winding 3 with a current 12 connected to an alternating voltage source 4. In the winding circuit 3 there is a current sensor 5. Identical amplifier-decoupling transformers 6 and 7 are connected to the current sensor, and two diodes 8 and 9 are included in the secondary windings of them. Capacitors 10 and 11 are designed for

smoothing. Resistors 12, 13 and 14 constitute a unit for subtracting the amplitude values of the half-waves of the secondary current. Indicator 15 is for registering a useful signal.

In the case where the current in the primary winding is absent 0 (0), i.e. the constant component of the flow is equal to zero, and the dependence 2vi2 f (y t) is symmetric. When And 0, a flow appears that biases IWsfnon and provides inequality AMPLITUDE SEMI-WAVE CURRENT (I2W2) (i2W2).

These half-waves, proportional to the half-waves of current z, are shown in FIG. 3, are smoothed by capacitors 10 and 11, and

form the levels of ab and cd. The useful signal obtained in the subtraction unit is equal to the difference of the levels ab and cd, is supplied to the indicator 15 and is proportional to the current I.

The technical advantage of the solution

simplicity of implementation, the possibility of manufacturing DC transformers based on electrical steel, widely used in serial transformer building, and the installation of the transformer without breaking the DC circuit.

Claims (1)

SUMMARY OF THE INVENTION A dc measuring transformer comprising a ferromagnetic core with a primary winding and a secondary winding having inputs for connecting to an AC source, a smoothing filter, characterized in that. in order to simplify the design, it has a current sensor, two identical amplifying-decoupling transformers, two diodes opposite connected, additional a smoothing filter, a unit for subtracting the amplitude values of half-waves of the secondary current and an indicator whose input is connected to the output of the unit for subtracting signals at the output of the smoothing filters, the inputs of which are connected via the corresponding antipolar diodes to the secondary winding of the amplifying-decoupling transformers, the primary windings of which are connected to the sensor output. FCE.Z Editor Compiled By Tsvetikov Tehred M. Morgenthal Corrector L. Fil