SU758023A1 - Device for testing magnetic elements - Google Patents

Description

The invention relates to the field of manufacturing technology of computer technology and can be used in the design of devices for automatic control of ferrite cores of computer storage devices.

 Known devices for monitoring ferrite cores of the specified purpose, containing a measuring needle connected to the source of excitation current and through a balancing transformer to the measuring device, as well as a generator of interrogating pulses and a threshold element connected to the additional winding of the transformer £ 1].

Their disadvantage is the lack of accuracy and performance measurements.

The closest in technical essence is a device that contains a measuring needle connected to the source of the excitation current and the measuring device, kinematically connected with the armature of the electromagnet containing the return springs [2 ^. In this automaton, the cores are individually fed to the measuring position, where they penetrate

They are called the measuring needle, made in the form of two isolated halves. One half of the needle is connected through a pair of contacts to the source of the excitation current, and the other through the second pair of contacts to the measuring device, resulting in a measuring circuit containing two electric circuits, in the first of which pulsed excitation currents circulate, and in the second - induced EMF arising from the magnetization reversal of the core.

However, in this automaton, due to 15 partial or total contact failures in the measuring needle circuit, which occur at high speeds of screening, the actual performance of the automaton and its accuracy decrease. To clarify these phenomena, we consider the dynamics of the measuring circuit.

Measuring needle, kinematically connected with the solenoid anchor,

25 after switching off the current in the latter, it makes a uniformly accelerated motion under the influence of return springs and by the time it enters the contacts it acquires greater speed. So 30 as contacts are fixed on

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kennyh levers, which together with the springs form an oscillating system, then as a result of the collision of the needle with the contacts, the process of their bounce begins. During the bounce time, there is no sliding of the contacts on the needle surface, and, consequently, mutual cleaning of the contact surfaces, which is one of the most effective means of ensuring reliable contact in conditions of unavoidable contamination of the needle and contacts with ferrite dust.

To ensure the required measurement accuracy, the monitoring of the pulse parameters of the cores in the measuring part of the machine can begin only after the needle stops completely and all dynamic processes associated with its movement: contact bounce, mechanical vibrations of the parts, etc., stop.

During the inspection interval, all parts of the mechanism must remain fixed. When creating high-performance machines, meeting this requirement causes great difficulties. The interval of control becomes commensurate with the duration of the full cycle of operation of the needle drive mechanism, which forces to reduce the time of its movement.

In this case, the needle can be stopped before the end of contact bounce, as a result of which their self-cleaning stops and a phenomenon of chaotic increase in contact resistance occurs, leading to increased control errors (if no failures were detected), or the contact is completely stopped. work to restore normal contact. Naturally, this leads to

reduce the actual performance of the machine.

The aim of the invention is to improve the accuracy and performance of the control.

This goal is achieved by the fact that the device containing a measuring needle connected to the source of the excitation current and the measuring device, kinematically connected with the armature of the electromagnet containing the return springs, is additionally equipped with a measuring needle position sensor, two threshold elements, a differentiating unit, a coincidence element and a power amplifier , wherein the output of said sensor is connected to the input of the first threshold element and the input of the differentiating unit, the output of the differentiating unit connected to the input of the second threshold

element, the outputs of both threshold elements are connected to the inputs of the coincidence element, and the output of the latter through the power amplifier is connected to one of the sections of the electromagnet winding, made of two in series and according to the included sections.

The newly introduced elements in the device form a pulsed braking system for the armature of the electromagnet, kinematically connected to the measuring needle. In this case, the initial part of the movement of the armature of the electromagnet, as before, makes under the influence of only return springs.

Starting from a certain moment, the system delivers braking impulses to the electromagnet and thus controls the movement of the measuring needle. Due to the selection of optimal ratios between device parameters, it is possible to achieve a law of motion in which the needle speed at the time of entering contacts decreases to a value at which their bounce is absent and then increases again. As a result, it is possible to improve the performance of grading while increasing the reliability of contacting.

.In FIG. 1 shows a functional diagram of a device for controlling magnetic elements; in FIG. 2 - timing diagrams explaining the operation of the device, where a) a diagram of the movement of the needle; b) the voltage at the output of the sensor 5; C) the voltage at the output of the differentiating unit 6;

g) the voltage at the output of the element 7;

d) the voltage at the output of the element 8;

e) the current at the output of the amplifier 10; 1) _P7 voltage threshold element 7; and _front voltage threshold of the element 8. The device contains a source of excitation current 1, the measuring needle 2, the measuring device 3, the electromagnet with return springs 4, the position sensor of the measuring needle 5, the differentiating unit 6, the threshold elements 7 and 8, the element of coincidence 9, the power amplifier 10, the coil of the solenoid 11 with the input 12.

The source of excitation current 1 through the current contacts. Connected to the measuring needle 2. The measuring needle through the removable contacts is connected to the measuring device 3. The measuring needle is kinematically connected with the armature of the electromagnet 4 containing the return spring. This connection can be practically realized, for example, by rigidly fixing the needle to the armature of the electromagnet. The electromagnet can be, for example, a solenoid type with a pull-in armature and spiral

five

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return springs. The output of the sensor position of the measuring needle 5 is connected to the input of the threshold element 7 and the input of the differentiating unit 6.

The output of the latter is connected to the input of the threshold element 8. The outputs of both threshold elements are connected to the inputs of the coincidence element 9. The output of the latter through the power amplifier 10 is connected to the winding section 11 of the electromagnet 4, made of two in series and according to the included sections. The coil 11 of the solenoid has an input 12.

The device works as follows. In the initial state, a current is fed to the coil 11 of the solenoid through the inlet 12, which holds the armature of the electromagnet in the attracted state, while the measuring needle is out of the contacts, and the needle position sensor 5 outputs a low voltage level at its output. At the output of the differentiating unit b there is zero voltage. The voltage at the inputs of the threshold elements 7 and 8 is less than the threshold, and the coincidence element 9 receives low levels. A low level from the output of the coincidence element enters the input of the power amplifier 10. At the same time, there is no current at the output of the latter.

After turning off the current in the electromagnet winding, the armature of the latter, with a measuring needle attached to it, begins to move under the influence of return springs. As the needle moves to the contacts, the voltage at the output of the sensor 5 begins to increase in proportion to the movement. Starting from the moment, the voltage value (linearly related to the speed of movement of the measuring needle) at the output of the differentiating unit b becomes larger than the threshold value of the threshold element 8, and a high voltage level is formed at its output. As soon as the voltage level at the output of the sensor 5 exceeds the threshold value of the threshold element 7, a high voltage level is formed at its output, which through the open element matches to the input of the amplifier 10.

In this case, the output of the amplifier in the winding section 11 of the electromagnet 4 will go braking current differential. The speed of movement of the measuring needle, and hence the associated voltage value at the output of the differentiating unit, begins to decrease. After some time, the voltage value becomes less than the threshold level of the threshold element 8, a low level from its output closes the coincidence element 9, a low voltage level is formed at the input of the amplifier 10 and the current in the electromagnet winding rushes to zero.

Due to the inertial properties of the system (the lag of the magnetic flux from the current in the electromagnet, the final value of the current off time in the electromagnet winding, etc.), the speed of movement of the measuring needle continues to decrease for some time, and then under the influence of the spring, the speed of movement of the needle increases to the value specified the value of the threshold of element 8, and until the end of the needle movement is kept constant.

The required law of motion of the measuring needle relative to the contacts for a given mass of the armature, the parameters of the electromagnet, return springs and power amplifier is ensured by selecting the magnitude of the decelerating current and the optimal levels of threshold circuits.

The use of the invention allows to reduce the likelihood of errors in the measurement of parameters of the cores and to increase the actual performance

Claims (1)

Claim Device to control the magnet. elements containing a measuring needle connected to the source of the excitation current and the measuring device, kinematically connected with the armature of the electromagnet containing return springs, characterized in that, in order to improve the accuracy and performance of the control, it is equipped with a measuring needle position sensor, two threshold elements, a differentiating unit, a coincidence element, and a power amplifier, the output of said sensor being connected to the input of the first threshold element and the input of the differentiating unit Single Exit differentiator block is connected to the input of the second threshold element, the outputs of both threshold elements are connected to the inputs of the coincidence element and the yield of the latter through the power amplifier associated with one of the sections of electromagnet windings made of two series of sections and according included.