SU1652830A1 - Device for measuring natural frequencies of reed relay contacting members - Google Patents

Abstract

The invention relates to a measurement technique and can be used in the research, development and production of sealed magnetically controlled contactor (reed switches). The purpose of the invention is to secure the technological capabilities of the device by providing measurement of the natural frequency of the mobile contact details of switching reed switches. The oscillations of the moving contact of the reed switch are created by a positive feedback circuit including a high-frequency generator 1, a diode 2, a low-pass filter 3, a feedback depth regulator 4, a power amplifier 5, an excitation coil 6. The oscillation frequency of the moving contact parts is recorded by the frequency meter 7. 2 Il. Sfi

Description

The invention relates to the field of measurement technology and can be used in the research, development and production of sealed magnetic contacts (reed switches).

The purpose of the invention is to expand the technological capabilities of the device by providing measurement of the natural frequency of the mobile contact details of switching reed switches.

FIG. 1 shows a functional diagram of a device for measuring the natural oscillation frequency of contact details of reed switches; Fig. 2 shows the direction of magnetization of the contact details of the switching reed switch.

A device for measuring the natural frequency of the contact parts of reed switches contains a series-connected high-frequency generator 1, a diode 2, a low-pass filter 3, a feedback depth controller 4, a power amplifier 5 and an excitation core 6, a frequency meter 7, whose input is connected to the first output an amplifier 5 of wrinkle, the second output of which is connected to the second input of the regulator 4 feedback depth, control unit 8, current source 9, successively connected the first resistor JO and the first magnetizing coil 11 a string shunt 12, the second resistor 13 and the second bias coil 14 with the magnetic shunt 15 are connected in series. The first, second and third outputs of the control unit 8 are connected respectively to the third input of the feedback depth controller 4, i to the trigger input of the frequency meter 7 and source input

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nick 9 current. The output of current source 9 is connected to the combined second terminals of the first and second resistors 10, 13. The second terminals of the excitation coil 6 and the bias coils 11, 14 are connected to a common wire. The feedback depth controller 4 may contain input amplifier 16 connected in series, phase shifter 17 and bandpass filter 18, automatic gain control unit 19 (AGC), the output of which is connected to the first input of the input amplifier 16. Second input of the input amplifier 16, unit 19 input AGC, the third input of the input amplifier 16 are the first, second and third inputs of the feedback depth controller 4, respectively. The output of the bandpass filter 18 is the output of the feedback depth controller 4. The input of the low-pass filter 3, the common point — the connections of the second resistor 13 and the second bias coil 14 and the common wire are respectively for communication with the first, second and third contacts of the controlled reed switch.

The device works as follows.

The controlled reed switch is placed in the zone of action of the magnetic fields of the excitation coils 6, 11 and 14 and under magnetisation, electrically connect its leads to the corresponding points of the circuit. After that, the control unit 8 begins to work, having carried out a predetermined sequence of effects on the controlled reed switch and interaction of the elements of the entire device. The pulse from the third output of the control unit 8 switches on the current source 9. At the initial moment of time, the output current of the source flows through the first resistor 10 and the first bias coil 11, as well as through the second reel 13, the second bias coil 14 is shorted by closed contact details of the reed switch. As soon as the magnetization of the closed contact parts reaches a value sufficient to open them, the currents are redistributed. Through the second bias coil 14, a current is required to flow, in order to magnetize the open-ended stationary contact part, in the direction that prevents the moving contact part from passing. First ka current

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In this case, the bias carcass 11 increases slightly, since by increasing the resistance of the second resistor 13 - the second bias coil 14, the currents are distributed in parallel circuits of the load of the current source 9. As a result, the movable contact part of the controlled reed switch moves to an intermediate position.

The required direction of magnetization of the contact details of the reed switch shown in FIG. 2 is provided by the antiphase connection of the first and second bias coils 11 and 14 to the output of current source 9. This also contributes to the magnetic shunts 12 and 15, located directly on the reed switch. Magnetic shunt 12 prevents magnetization of the open contact details of the reed switch with bias coil 11, magnetic shunt 15 prevents magnetization of the second bias coil 14 with moving and closed contact parts of the reed switch. The resistance values of the first and second resistors 10 and 13 and the output current of the current source 9 are adjusted during adjustment based on the neutral position of the movable contact part of the reed switch.

The selected order of current supply to the first and second bias coils 11 and 12 makes it possible to impart initial oscillations to the moving contact of the reed switch, which ultimately improves the conditions of self-excitation of the system.

The voltage from the output of the high-frequency generator 1 is fed to the diode 2, which together with the contact part connected to it and the reed contact moving part connected to the common wire, forms a capacitive voltage divider whose upper arm is formed by the capacitance of the diode 2 and the lower one - the capacity between the contact parts of reed switches. The value of this capacity depends on the relative position of the contact parts of the controlled reed switch. As the contact parts approach each other, the capacitance between the contact details of the reed switch increases, and decreases with removal. At a constant input impedance of the low pass filter 3, the magnitude of the high frequency voltage across its

the bone between the contact-parts of the reed switch ;; i

Thus, if the contact details

Since the controlled reed switch oscillates, the high-frequency voltage at the input of the low-pass filter 3 will be modulated by low-frequency oscillations, the frequency and phase of which strictly correspond to the frequency and phase of the oscillations of the contact parts.

Since in one of the half-cycles of the high-frequency voltage, diop 2 is open and the other is closed, this modulated voltage will be simultaneously detected.

The high-frequency components of the spectrum of the resulting signal are filtered out by using a low-pass filter 3 of the lower frequencies, and from its output to the input of the regulator 4 - the feedback depth receives electrical oscillations with a frequency equal to the frequency of natural mechanical vibrations of the contact parts. The electrical oscillations are amplified by the input amplifier 16, their phase is corrected by the phase shifter 17, and the band-pass filter 18 eliminates interference and passes oscillations only in a small range of expected frequencies corresponding to possible natural oscillation frequencies of contact parts controlled by a reed switch, after which these oscillations are amplified by power amplifier 5.

Enhanced sinusoidal oscillations of the electric current with a frequency and phase corresponding to the frequency and phase of the natural oscillations of the studied contact parts of the controlled hermetic, formed in controller 4

feedback depths are applied to the excitation coil 6, where their energy is converted to the energy of a magnetic field in a variable direction. The resulting alternating magnetic field effects the contact of the reed switch part to maintain undamped natural oscillations in them. To prevent the oscillation amplitude from growing or damping, the contact of parts in the described auto-oscillatory system has an automatic gain control unit 19 that controls the gain of the input amplifier, which ensures a constant amplitude of oscillations in this

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contact between the oscillating contact details of the reed switch occurred. As a result, stable oscillations occur in the system with a frequency corresponding to the natural oscillation frequency of the studied contact-part of the controlled reed switch. A frequency meter 7 connected to the output of the power amplifier 5 is used to measure this frequency.

When measuring the natural oscillation frequency of the closing reed switches, magnetic shunts 12 and 15 are not used, and the second bias coil 14 is used.

F o

rmula of invention

A device for measuring the natural frequency of contact details of reed switches, containing a series-connected high-frequency generator, a diode, a low-pass filter, a feedback depth controller, a power amplifier and an excitation coil, a frequency meter whose input is connected to the first output of the power amplifier, the second the output of which is connected to the second input of the feedback depth regulator, the control unit, the first and second outputs of which are connected respectively to the third input of the feedback depth regulator and to the trigger input of the frequency meter, the second output of the excitation coil is connected to the common wire, the input of the low-pass filter is designed to communicate with the first contact of the controlled reed switch, characterized in that, in order to expand the technological

capabilities, it is provided with a source

the third output of the control unit, serially connected by the first resistor and the first bias coil with a magnetic shunt, sequentially connected by the second resistor and the second bias coil with a magnetic shunt, the second terminals of the first and second resistors are combined and connected to the output of the current source, the second terminals of the first and second the bias coils are connected to the common wire, the common connection point of the second resistor and the second bias coil and the common wire of the device is designed to connect and respectively with the second and third contacts of the controlled reed switch.

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Claims (1)

SUMMARY OF THE INVENTION A device for measuring the frequency of natural oscillations of contact parts of reed switches containing a high-frequency generator, a diode, a low-pass filter, a feedback depth regulator, a power amplifier and an excitation coil, a frequency meter whose input is connected to the first output of the power amplifier, the second output of which connected to the second input of the feedback depth controller, the control unit, the first and second outputs of which are connected respectively to the third input of the depth controller s feedback and to the starting input of the frequency meter, the second output of the excitation coil is connected to a common wire, the low-pass filter input is designed to communicate with the first contact of the controlled reed switch, characterized in that, in order to expand technological capabilities, it is equipped with a current source, the input of which is connected to the third 'output of the control unit, connected in series with the first resistor and the first bias coil with a magnetic shunt, connected in series with the second resistor and the second coil magnetization with a magnetic shunt, the second terminals of the first and second resistors are combined and connected to the output of the current source, the second terminals of the first and second magnetization coils are connected to a common wire, the common point of connection of the second resistor and the second magnetization coil and the common wire of the device are designed to communicate respectively with the second and the third contacts of a controlled reed switch.