SU748285A1 - Device for testing single-turn inductance of ferrite cores - Google Patents

Description

one

The invention relates to the field of automatic control and can be used in control and sorting machines for disassembling forging of ferrite cores according to the value of single-turn inductance (initial inductance coefficient) during production.

A device for measuring and monitoring the components of the impedance of various objects, such as ferrite cores, containing a compensation or bridge measuring circuit, a reference current generator, a core holder, actuators and indicators is known.

U1.

This device allows to obtain the result of testing the cores only after complete equilibration of the measuring circuit and is characterized by the fact that when measuring even one meter (single-turn inductance), the balance of the measuring circuit-25 pi is carried out on both components of the core impedance. ,

The closest technical. the essence of the invention is measurable

An inductance generator containing a sinusoidal current generator, to the output of which a current-setting resistor and a core holder are connected in series, a digital voltage divider whose reference input is connected to the generator output, a phase-shifting device, a comparator unit, one input of which is connected to the core holder., amplifier, input which is connected to the output of the comparison unit, a phase-sensitive detector, a control unit and an indicator 2.

When monitoring cores, a known meter allows to obtain a control result only after complete balancing of the measuring circuit. When the cores are monitored by one parameter (single-turn inductance), to ensure the required accuracy, a known meter balances the measuring circuit along both components of the complex resistance of the ferrite core, for which a second equilibration channel is provided, which complicates measuring the cable.

Thus, in a known device, when balancing with one component of resistance, the heart cannot be provided sufficiently for measurement accuracy, and with balancing on both components, to increase accuracy, the device is significantly complicated. The purpose of the invention is to increase the availability of control. This is due to the fact that the described device for controlling single-turn inductance of ferrite cores containing a sinusoidal current generator, to the output of which a current-generating resistor and a core holder are connected in series, a digital voltage divider whose reference input is connected to the generator output, block comparison, one input of which is connected to the core holder, and the other to the output of the voltage divider, an amplifier, the input of which is connected to the output of the comparison unit, after a phase-sensitive detector, the reference input of which is connected to the output of the phase-shifting unit, indicator and control unit, the output of which is connected to the second input of the indicator, is equipped with a parameter connected between the amplifier and the phase-sensitive detector and a frequency doubler connected between the output of the phase-shifting unit and the pump input is parameterized, the second input of the frequency output is connected to the output of the control unit, and the DC power supply is connected to the parameter. The use of a parametron in the proposed device, connected between an amplifier and a phase-sensitive detector, makes it possible to significantly reduce the gain of the unbalance amplifier. The parametron has a higher phase sensitivity, and for its excitation, a considerably smaller amplitude of oscillations is sufficient, which allows reducing the gain to 10,100 and thereby reducing its phase instability. The remaining phase fluctuations are, moreover, corrected by a metron, at the output of which the oscillation phase always has one of two mutually opposite values. The result of the control is obtained by one-by-one comparison, balancing the measuring circuit is not required. FIG. 1 shows a functional diagram of this device; in fig. Figure 2 shows a stress vector diagram. The device includes a sinusoidal current generator 1, a current-carrying resistor 2, a core holder 3, consisting of insulated, current 4 and 5 potential parts, a controlled core 6, a comparison unit 7, a digital voltage divider 8, a phase-shifting unit 9, the amplifier 10, the parametron 11, the frequency doubler 12, the DC source 13, the phase-sensing detector 14, the indicator 15 and the control unit 16. The device operates as follows. Through the current part 4 of the holder of the cores 3, a sinusoidal current flows from the generator 1. On the potential part 5 of the holder 3 in the presence of a controlled core 6, a voltage is induced, the amplitude .O. (Which is proportional to the impedance of the core 2, .. This voltage is applied to the first input of the unit 7. The current in the current part of the holder 3 is determined only by the resistance of the current-setting resistor 2. The voltage from the output of the generator 1 through the phase-shifting unit 9, the phase shifting by 90 °, is fed to the reference input of the digital voltage voltage 8. The output voltage of the divider 8 supplied to the output of the comparison block 7 is tan, the transfer coefficient of the divider 8 numerically equal to the control value of a single-turn inductance expressed in nanogenry or mikrgenri and multiplied by Yu, where m is a positive integer the transmission coefficient of the phase-shifting unit 9; the voltage amplitude at the output of the generator 1. The number N is set at the digital input of the voltage divider 8 before starting operation using switches on the front panel of the device. The voltage 0 at the output of the comparison block 7 is proportional to the sum of the voltages on its inputs and consists of two components: active UR and reactive jU. The reactive component is inductive or capacitive in nature depending on the ratio of L values) (and N. The nature of the reactive component of the output voltage of the comparison block 7 is a carrier of information about the belonging of the controlled core to one or another sorting group. 0 is a quadrature interference and a source of errors during sorting. From the output of the comparator unit 7, the voltage is applied to the input of the amplifier 10. If a phase transition occurs in the amplifier

voltage shift 0, then the character of voltage O at the amplifier output, as shown in Fig. 2 (voltage at the amplifier output, If - voltage phase shift in the amplifier,), resulting in sorting 5 will be incorrect, because the reactive component of the voltages at the input Uj and at the output U usi-t itel has opposite phases.

In the proposed device, the amplifier has a small gain (10-100), so the phase shift of the amplified signal is insignificant. The use of an amplifier with a small gain factor is possible "because the voltage from its output is fed to the input of parameter 11, for

the excitation of which is sufficiently small amplitude of oscillations. After applying voltage from the amplifier output to the parametron input, the control unit 16 delivers an enable signal to the frequency doubler 12, which produces

pump voltage for parameter.

Output parametron after filing

pump voltage takes place the process of 5 setting oscillations with a frequency equal to the frequency of the generator 1, and a phase receiving one of two mutually opposite values and always coinciding exactly with the phase of the reactive component of the voltage at the output of the comparator unit 7. At the same time, the parametron serves as a limiter voltage, regardless of the value of the signal amplitude at the parametron input 35, the amplitude at its output is constant. From the output of the parameter, the voltage is applied to the phase-sensitive detector 14, the reference voltage to which is supplied from the output of the phase-shifting unit 9. The polarity of the voltage at the output of the phase-sensitive detector 14 is determined by the phase voltage on its input. From the output of the phase-sensitive detector 14 j, the voltage is applied to one of the inputs of the indicator 15, which serves as the actuating element of the core screening device.

After a period of time necessary for the termination of transients in the parametron, to the second input

the indicator 15 from the output of the control unit 16 is supplied with the resolving potential, and the indicator is triggered, i.e. it takes one of two stable states: depending on Tgr, the value of the initial inductance coefficient of the core of the control value N set at the digital input of the voltage divider is greater or not greater .

Claims (2)

1. Authors certificate USSR 391497, class, G 01 R 27/26, 1975. 2. Bersudsky A.A. , LinDunen V.I. Digital instruments for measuring coils with ferrite cores. Instruments and control systems, 1971, .№ 7, p. 33-34 (prototype). 748285