SU807242A1 - Device for determining sealed contact quality - Google Patents

Description

one

This invention relates to electro. technology and can be used to determine the current-voltage characteristics of the start of the spark work of the reed switch, in particular with liquid metal contacts, as well as de-screening of the reed switches according to the state of the contacting surfaces.

There are known computational methods for defining the current-voltage characteristic of the onset of arcing (VAHI) of reed switches with a spark-proof target 1.

However, they are not accurate, since they do not take into account the influence on the VAHI of the parameters of the control of the operation of the reed switch as well. also the possibility of sparking with a nanosecond duration of low intensity and the possibility of surface films on the contacts.

A device for determining a reed switch quality is known, comprising a power supply unit, terminals for connecting a reed switch, a reed switch installation unit, a reed switch switching control unit, a reed switch load unit and an indication and recording unit of the current-voltage characteristics of the reed switch, and the control unit

ipKOHi

.12.

water reed switch

A disadvantage of the known device is that it is unsuitable for determining the VAHA of the reed switch placed in the drive and determining the dynamic resistance of the spark and surface films in the nanosecond time range.

The purpose of the invention is to provide the possibility of controlling the dynamic resistance during switching and the contact resistance of surface films in the nanosecond range with a resolution of about 10 s.

The goal is achieved by the fact that a device for determining the quality of a reed switch containing a power supply, terminals for connecting a reed switch, a reed switch installation unit, a reed switch switching control unit, an x-Hercon load unit and a parameter display and recording unit, current-voltage characteristic a reed switch, a reed switch switching control unit is connected to a reed switch drive, a storage unit in the form of long lines and a delay unit are entered, the input of the load unit is coordinated with the storage unit and connected to it via a key capacitance to connect the reed switch, the output of the load unit is connected through the delay unit to the display unit and recording the parameters of the volt-ampere characteristic.

At the same time, in the device the load cell of the reed switch can be made low-voltage with output voltage | 0.001-1 V,

FIG. 1 shows a block diagram of the device; in fig. 2 and 3 waveforms, explaining the principle of the device.

The device (Fig. 1) contains a load power supply unit 1 connected to the storage unit 2 in the form of long lines, which through the reed switch installation unit 3 and the test reed switch 4 is connected to the load unit 5 coordinated with the unit 2. To block 5 through block 6 delays with an advanced clock pulse coupler connected to the block 7 of the display-registration parameters VAHA reed switch. The drive 8 is structurally located in the block 3 of the reed switch installation 4 (in general, it is not about (; necessarily) and is connected to the reed switch switching control unit 9. The block b may be absent.

The device works as follows.

From the power supply unit 1 of electric loads, having an adjustable output voltage, the storage unit 2 is charged, which is selected by the characteristic impedance, in order to provide the required mode for the load current of the reed switch 4. The reed switch 4, the storage unit 2 is connected to the matched load unit 5, which produces a pulse-potential electric signal, which is an informative signal about the mode of the accumulator's discharge (Fig. 2 and 3), which is fed through the delay block b to the display-register block 7 tion wahy. The frequency of the pulsed-potential signals generated is determined by the frequency of the switching control pulses by the reed switch 4, which are fed to the reed switch drive from block 9.

In the absence of sparking contact of the reed switch 4 and the absence of surface films, informative signals are obtained with the shape shown in FIG. 2. If the contact is damaged or surface films are present, informative signals of a distorted shape are obtained on it. When, during switching, a spark occurs before the contacts are closed, then at the output of block 7 a sequence of pulses is obtained, the shape of which is shown in FIG. 3

The instantaneous value of the dynamic resistance of a spark is determined by the ratio of the amplitudes (ordinates) of the pulsed-potential signal at sections 10 and 11, and the duration of the existence of the claim. 10 according to the duration of section 10 or 12. The resistance of the spark can also be found from the amplitude section 12, if the voltage U of the accumulators charge U is given out by block 1. The voltage in sections 10-12 is defined by the expressions respectively

a, 5 (Uo-u.A); o., 5-u;

AZo 0.5-id, where 3i is the Shepi spark current);

Q is the impedance of the accumulator;

and - the voltage of the spark (short

arc).

Similarly, one can determine the dynamic resistance of surface films when closing a contact in the zone of non-spark KONo yTa modes. The voltage at the output of unit 1 is then taken less than 1 volt to avoid electrostatic disturbance of the state of the surface pleno during the screening of the test reed switches, especially with liquid metal contacts. When testing reed switches with the purpose of determining their quality with regard to the presence or absence of contaminations in them capable of organizing surface films on the surfaces of the switching contact, sections 10-12 (Fig. 3) are not expressed on the informational pulse-potential signal, since film resistance varies over wider ranges. By performing the device in accordance with the requirements for the broadband paths, it is possible to achieve a resolution over time in the order of fractions of a nanosecond. The advantage of this device is that the information signal sections 10 and 12 for small sections 11 are equivalent, which in this case makes it possible to get by at the input of block 7 without block 6 of the delay necessary for generating the forward clock signal j of triggering block 7. When starting block 7 directly by the front of the information signal and used to determine the quality of the reed switch of section 12 of this signal in a number of cases it is possible to reduce the insertion loss and thereby reduce the measurement error.

Claims (2)

1. A device for determining the quality of a reed switch containing a power supply unit, a clip for connecting a reed switch, a reed switch installation unit with a reed switch drive, a reed switch switching control unit, a reed switch load unit and a reed switch characteristic recording and recording unit, the reed switch switching control unit Connected to a reed switch, characterized in that, in order to provide  possibilities of controlling dynamic resistance during switching and contact resistance of surface films in the nanosecond range, a storage unit in the form of long lines and a delay unit are entered into it, the input of the load unit is matched with the storage unit and connected to it via terminals for connecting the reed switch, output unit load, eq is connected through the delay unit to the display unit and the registration of the parameters of the current-voltage characteristic. 2. The device according to claim 1, of which is in order that expanding the field of application and improving the accuracy of determining the daily resistance during switching, the load cell of the reed switch is made low-voltage. Sources of information taken into account in the examination 1.Denisov A.G. and Zinakov V.K. .. Iskrozashchita protection of contacts gerkonrv. Reviews on electronic engineering. Issue 28 (177), P., Central Research Institute, Electronika, 1973. 2. USSR author's certificate fP 465668, cl. H 01 H 49/00, 1975. V F.-9. 2 Vlj Rig. five