SU855571A1 - Device for measuring ferromagnetic material static magnetic characteristic - Google Patents

Description

(54) DEVICE FOR MEASUREMENT OF STATIC MAGNETIC CHARACTERISTICS OF FERROMAGNETIC MATERIALS

one

The invention relates to a magnetic measuring technique, in particular to testing ferromagnetic materials and measuring their static magnetic characteristics on core samples magnetized in an open circuit, and can be used to record the basic magnetization curve and magnetic hysteresis loops and a two-coordinate recording instrument.

A device for oscillography of magnetic hysteresis loops with a patch probe is known. The device contains a series-connected magnetizing system made in the form of a Helmholtz coil or a solenoid, a reference resistor and an oscilloscope vertical scan input, a ferrosonde probe located on the surface of the ferromagnetic sample under test, and a magnetometer whose output is connected to the horizontal scan input of the oscilloscope 1.

A disadvantage of the known device is that of measuring the accuracy of a pair of magnetic hysteresis loops (except for residual magnetization), due to the fact that the intensity of the external magnetizing field is not directly related to the magnetization of the test specimen. Therefore, the installation allows only to register certain conditional magnetic hysteresis loops, only from individual points (residual magnetization) of which one can judge the actual parameters of the ferromagnetic material.

The purpose of the invention is to improve the measurement accuracy.

This goal is achieved by the fact that a device for measuring the static magnetic characteristics of ferromagnetic materials, contains a magnetizing unit in the form of a Helmholtz coil and associated

Claims (1)

20 with units for measuring the intensity of external and internal magnetizing fields, the output of which is connected to the horizontal scan input of a two-coordinate recording of any instrument, with the unit for measuring the intensity of external magnetization. the field is made in series with the magnetizing unit of the reference resistor and magnetizing current meter, and the measuring unit of the internal magnetizing field is made in the form of serially connected ferrosonde polymer and magnetometer, equipped with a subtraction unit, the first and second inputs of which are connected respectively to the outputs of the voltage measuring units These are external and internal magnetized fields, and the output is to the input of a vertical sweep of a two-coordinate recording device. The drawing shows a functional diagram of the device proposed. The diagram of a device for measuring static magnetic characteristics of ferromagnetic materials on rod samples magnetized in an open magnetic circuit contains a magnetizing unit 1 made in the form of Helmholtz coils, the JSifi test ferromagnetic sample 2, unit 3 measuring the intensity of the internal magnetic field, an internal ferromagnetic sample 2, unit 3 measuring the stresses of the internal magnetic field, an internal magnetism on the internal magnet. field 3, unit 4 for measuring the intensity of an external magnetizing field, reference resistor 5, meter 6 for magnetizing current, calculating ayuschy unit 7, 8 polemer flux gate magnetometer 9 and biaxial registriruk "tions device 10. magnetometers and flux gate 9 - polemer 8 are not other than the caliper of the strength of the magnetizing field inside it with the transmitter. The functions of the transmitter and the meter of the external magnetizing field are performed by the reference resistor 5 and the magnetizing current meter 6. Ferrosonde - field meter 8 is located on the surface of the ferromagnetic sample under test 2 and is connected to the input of the magnetometer 9, the output of which is connected to the horizontal scan input of the two-coordinate recording device 10 and the second input of the readout unit 7, the input of the magnetisation current meter b is connected to the reference resistor 5, and the output - to the first input of the subtracting unit 7, the output of which is connected to the vertical input of the two-coordinate recording device 10. The device operates as follows. The ferromagnetic sample 2 under test is magnetized by an external uniform field H | g of the Helmholtz coils forming the magnetizing unit 1. The voltage drop across the reference resistor 5 is proportional to the intensity of the magnetizing unit 1, i.e. The signal C. at the output of the meter 6 entering the unit 4 for measuring the intensity of the external magnetizing field is determined by the following relationship :. -JO is where K is the constant coefficient. Since, due to the principle of continuity, the tangential component of the intensity of the magnetizing field ti on the surface of the ferromagnetic sample 2 is equal to the intensity of the internal magnetizing field H-, the signal and, at the output of the magnetometer 9, included in the unit for measuring the intensity of the internal magnetizing field, equal to: where K is a constant coefficient. At the output of the subtracting unit 7, a signal U7 is formed, which is proportional to the intensity of the demagnetizing field H. U ,, - 4He-H.) - kHj - (3) Thus, on the two-coordinate recording device 10, when the current magnitude changes to this current, the magnetic hysteresis loop is recorded in the coordinates HO of N3, N. according to the sawtooth law. Since standard samples N «« const for uniformly magnetized in an open magnetic circuit, we can talk about measuring the magnetic hysteresis loop by magnetization. The error in measuring the magnetization for large values of y, tends to the error in measuring the intensity of the external magnetizing field, and is determined mainly by the error in the demagnetization coefficient. The device, in comparison with the known, possesses high accuracy and sensitivity and permits testing of ferromagnetic materials with a high magnetic permeability in an open magnetic circuit. Claims An apparatus for measuring the static magnetic characteristics of ferromagnetic materials, comprising a magnetizing unit in the form of. Helmholtz coils and connected with the Vulces of measuring the intensity of the external and internal magnetizing cages, the output of which is connected to the horizontal scan input of the two-coordinate recording device, while the unit for measuring the intensity of the external magnetizing field is made in series with the magnetizing unit of the reference reefer cage and the clearing cage clecter clever; current, and the unit for measuring the internal magnetizing field is made in the form of a series-connected ferrosonde - the field meter and a magnetometer, characterized In order to increase the measurement accuracy, it is equipped with a subtracting unit, the first and second inputs of which are connected respectively to the outputs of the voltage measurement units of the external and internal magnetizing fields, and the exit - to the entrance vertical / ,eleven  .. scanner of a two-coordinate register for a device. Sources of information taken into account in the examination .1. “Factory laboratory, 1978, 6, p. 713. L ..