RU1775746C - Electromagnetic relay wear resistance predictive nondestructive testing method - Google Patents

Description

The invention relates to electrical engineering and control and measuring equipment and can be used for predictive non-destructive testing of the wear resistance of e / 1 electromagnetic relays when switching the load-load causing an arc or game on the contacts in the conditions of production and operation

i / methods and devices are known for controlling electromagnetic wear resistance based on the determination of collapse failures (non-closing and poking of short-circuiting and opening- or silt-faults caused by the destruction of 1 (|) / s cot-contact contact and gamma kong 1) MRI Or u QUANTITY I ve inclusions

and shutdowns (on the order of tens of thousands of hours) of the tested relays

The disadvantages of this method are its low productivity, the impossibility of detecting all types of failures (the impossibility of detecting a tee and simultaneously closing the make and break contacts), the need for the relay to work during the control process is almost complete wear and low, and the reliability of the control results is low because the assessment the abrasion bones of the total number of rops made are given according to the results of the control ij ° ntcx e AOFS OKTECHOR and the software limited to 6

ate

Closest to the technical nature of the proposed method is the control of switching products, based on the control, in addition to contacting the contacts, also the total switching time of the contact, which is the sum of the time of the bounce of the opening contact, the flight time of the switching contact and the time of the bounce of the making contact, at which as a product with insufficient wear resistance, one is recognized for which the indicated total switching time exceeds a predetermined rate,

Checking the switching product according to the known method due to the increase in the amount of information about the tested product allows to reduce the monitoring time and not to bring the tested product to the state of contact wear.

At the same time, the known method is characterized by a low reliability of the results of checking the wear resistance of the product, due to the fact that the occurrence of non-contacting contacts with a small number of on and off products (from units to tens of times) does not reflect wear resistance, and the main parameter characterizing the reduced wear resistance in the known method , - the increased total time of the rattling of the NC contact, the flight of the switching contact and the rattle of the NC contact weakly reflects the controlled wear resistance and is not very informative as a criterion of reduced wear resistance for the following reasons.

A significant excess of bounce time in some cases may indicate a defect in the relay, in particular, reduced contact pressure. However, from the point of view of predicted wear resistance, this parameter is not sufficiently informative since reduced contact pressing is not a determining factor in reducing wear resistance. Contact pressing mainly determines the resistance of the contact circuit, which practically does not affect the wear of the contacts when switching high load currents, provided that an arc or spark occurs on the contacts. In addition, it should be noted that the duration of the bounce of both the closing and opening contacts is a rather unstable value for each relay instance, which can significantly differ from the previous value in any switching cycle, including significantly exceeding the previous value. A marked episodic increase in bounce time also occurs with a significant mass of relays that have a sufficient margin of wear resistance and do not have any manufacturing defects, including deviations of the contact pressure from the norm.

Similar errors when sorting products according to the known method are also caused by classifying the product as one with reduced wear resistance with an increased flight time of the switching contact, because an increase in comparison with the average value of the flight time can be caused not by a reduced speed of movement of the mobile system, which is accompanied by a reduced wear resistance of the product, but can also be caused to a large extent by the increased contact gap, which takes place 0 for products with high wear resistance.

When flying a switching contact in the known method, the speed of movement of the switching contact is not taken into account. 5 which determines the duration of the burning of an arc or spark, and on which erosion and transfer of contact material are largely dependent.

Naturally, since in the known method 0, each of the components of the total contact switching time, i.e. the bounce time of the NC contact, the flight time of the switching contact, and the bounce time of the NO contact is uninformative to assess the wear resistance of the product, and the total contact switching time is not a reliable indicator of the wear resistance of the product. 0 The aim of the invention is to increase the reliability of non-destructive testing of predictive testing of the wear resistance of an electromagnetic relay.

This goal is achieved by the fact that 5 in a non-destructive predictive method of controlling the wear resistance of an electromagnetic relay, in which a rectangular voltage pulse is supplied to the winding, the amplitude of which corresponds to the nominal operating value for a relay of this type and the duration of which exceeds the maximum possible for this type of relay the response time, and measure the flight time of the switching contact 5 during operation and the flight time of the switching contact when released, according to the invention, time m trip switching contact when measured is measured as the time from the moment of the first break of the opening circuit

contact until the moment of the first closing of the circuit of the make contact, the flight time of the switching contact when released is measured as the time from the moment of the first break of the circuit for:: closing contact until the moment of the first closure of the circuit of the opening contact, the measured values of the flight times during operation and release are remembered, again they supply rectangular voltage pulses with a duration exceeding the maximum possible response time for this type of relay, the amplitude of which is gradually increased, starting from The value corresponding to the minimum possible value of the tripping voltage for this type of relay, at each tripping, a signal proportional to the current of the relay winding is extracted, it is differentiated, the amplitude of the voltage pulses supplied to the relay winding is stopped, after during the next actuation of the relay during the stop, the shock swing obtained by the specified differentiation of the derivative of the winding current from one polarity to the opposite polarity reaches a predetermined value, dawn set for this type of relay, when the magnitude of the jump in the derivative of the winding outflow reaches a predetermined value, the switching contact’s flight time during operation is measured and remembered as the time from the moment of the first break of the NC circuit to the moment of the first closure of the NC circuit, the coefficient is calculated, characterizing the flight speed of the switching contact during operation when a nominal operating voltage is applied to the winding, according to the formula

Xrab.

tn bedtime tn sstab

where is Xrab. - a coefficient characterizing the flight speed of the switching contact during operation when a nominal operating voltage is applied to the winding;

1p.snom the time of flight of the switching kongaa during operation when a nominal operating voltage is applied to the winding;

tn. when the switching contact flies during operation when the amplitude of the jump in the derivative of the winding current reaches the specified value, the coefficient characterizing

5 10 15 20 25 30 5 0

5

0

5

switching ynt- flight speed. This is in the process of releasing when removing from about O windings of the rated operating voltage according to the formula

 ° nom

. g

1p STAB.

where is kotp. a coefficient characterizing the flight speed of the switching contact during the release process when the rated operating voltage is removed from the winding.

tn.QHOM time of flight of the switching contact during the release process at. removing the rated operating voltage from the winding;

ps, the switching time of the switching contact during the operation when the amplitude of the jump in the derivative of the winding current reaches the specified value, a relay with a calculated value of the coefficient Ksrab is recognized as a relay with reduced wear resistance of the opening contact. exceeds the value previously set for a relay of this type -, and as a relay with reduced wear resistance of the make contact, one with a calculated value of the coefficient Kotp is recognized. exceeds the value previously set for this type of relay.

The criteria for conformity of the wear resistance of the electromagnetic relay to a predetermined rate substantially differ in the known and proposed methods.

Controlled by a known method, the total time of the rattling of the NC contact, the flight of the switching contact and the rattle of the NC contact does not adequately reflect the wear resistance of the relay, because depends, besides the controlled parameter, on a number of factors.

A different combination of these factors in different instances of relays of the same type is not taken into account in the known method, which leads to errors in identifying relays with insufficient wear resistance.

In the control according to the proposed method of wear resistance, each of the instances of the tested relay determines the ratio between the time of the switching contact, which is measured at the operating power supply conditions of the winding, and the flight time of the switching contact at the same speed provided for all i instances of the DRIMSRNI-I OP, which is provided with rear feed and digging

the magnitude of the jump of the derivative of the winding current

Since the time of flight of a switching contact, measured at the same speed of movement of the core, is equally proportional to the size of the contact gap for all instances of the tested relays, thus, the ratio between the time of flight, measured during operating modes of power supply to the winding, and the flight time, exactly corresponding to the contact gap allows you to determine how fast the switching contact moves in the gap when applying or removing the operating voltage from the winding and unambiguously identify those relays for which this velocity is unacceptably low, resulting in an increase in the duration of arcing at the contacts (especially when switching an inductive load).

Thus, with a high degree of reliability, it is possible to detect, according to the proposed method, instances of relays with low switching ability.

Figure 1 shows a functional diagram of a device for implementing the proposed method; Fig. 2 is a timing diagram describing the operation of the device when measuring the time of flight of a switching contact during feeding and removing the rated operating voltage from the relay coil; Fig. 3 is a timing diagram of currents and voltages that characterize the operation of the device when measuring the flight time of a switching contact that strictly corresponds to the size of the contact gap.

The device contains a microcomputer 1, the first output of which is connected to the input of the digital-to-analog converter (DAC) 2, and the second output is connected to the control input of the meter 3 time intervals.

The output of the DAC 2 is connected to the control input of the controlled DC voltage stabilizer 4, to the output of the stabilizer 4 is connected the coil 5 of the controlled relay, connected in series with resistor 6. Parallel to resistor 6, the input of the differentiating device 7 is connected, the output of which is connected to the input of the unit analyzer 8 of the magnitude of the jump in the derivative of the winding current. The output of block 8 is connected to the first input of the microcomputer 1, the second input of which is connected to the output of block 3.

A switching contact 11 of the relay under test is connected to the output of the contact power supply 9 through the load resistor 10, the opening contact 12 and the making contact 13 of which are connected to the common (zero) bus of the device. To the switching contact 11 is connected to the information input of the meter 3 time intervals.

The device operates as follows.

At the beginning of the test, the relay of the microcomputer 1 gives a digital code on the first output,

causing the output of the DAC 2, the appearance of the corresponding analog signal, upon receipt of which a rectangular voltage pulse is applied to the input of the stabilizer 4 to the coil 5 of the controlled relay. the amplitude of which is equal to the rated operating value.

The duration of the indicated voltage pulse supplied to the winding 5 of the tested relay is set by the microcomputer 1 s

so that it exceeds the maximum possible response time for a given type of relay. In the process of supplying and then removing the voltage from the winding 5 of the tested relay, the time interval meter 3 uses the corresponding signals from the second output of the microE & M 1 to measure the flight time of switching contact 11 when it is triggered and released. In this case, the trip time of the switching contact 11 during operation is measured as the time from the moment of the first breaking of the NC contact circuit to the moment of the first closing of the NC circuit (time interval tn.c.HOM. In the diagram UBx. Block 3, figure 2), and the time when the release of the switching contact 11 when released is measured as the time from the moment of the first break of the circuit of the make contact to the moment

the first circuit of the NC contact (see the time interval of the throne on the UBx diagram of block 3, figure 2). Measured by block 3 values of the flight time of the switching contact when activated and

After releasing the tested relay, they arrive at the microcomputer 1 and are stored in its memory.

After measuring and memorizing the tn value by sleep and p.Normal, the device switches to the measurement mode of the flight time of switching contact 11. strictly proportional to the size of the contact gap. The measurement of this parameter is carried out as follows. According to the digital signals of the microcomputer 1 converted by the DAC 2 to the corresponding analog values, the stabilizer 4 starts to produce rectangular voltage pulses, the duration of which exceeds the maximum possible response time for this type of relay. In this case, the amplitude of the first pulse is equal to the minimum possible value of the voltage to switch off this type of relay, and the amplitude of each of the subsequent pulses is larger than the previous one by a value chosen from the condition of ensuring the necessary measurement accuracy.

In Fig. 3, the diagrams with the letter a show the voltages and currents in the device when applying to the coil 5 of the tested relay the minimum voltage value at which the operation occurs, and the diagrams with the letter b show the voltages and currents in the device when the jump of the derivative of the current of the winding 5 has reached a predetermined value,

During the operation of the tested relay, the current of the winding 5 rises according to a certain law, while the stopping times correspond to points A on the curves of 10 bm.

With each actuation of the relay under test, a signal proportional to the current of the winding 5 is removed from the resistor 6 and fed to the input of the differentiating device 7. The output voltage of which corresponds to the derivative of the winding current

d exchange

5 tested relays (diagram

d t

fig.Z). The output sip ep of the differentiating device 7 is controlled by an analyzer unit 8 of the magnitude of the jump in the derivative of the current of the winding and at the value of the voltage across the winding 5 of the relay under test, at which, during stopping, the amplitude of the indicated jump in the derivative from one polarity to the opposite polarity reaches a predetermined value predetermined for a given type of relay, the analyzer block 8 generates a signal supplied to the first input of microcomputer 1. When this signal is received, microcomputer 1 stops the amplification of the output pulses of the stabilizer 4 and the indicated amplitude at the subsequent voltage pulse is maintained at the achieved level. When the marked subsequent pulse is supplied by the command of the microcomputer 1, the time interval meter 3 measures the time from the moment of the first breaking of the circuit of the opening contact 12 to the moment of the first closing of the circuit of the closing contact 13, i.e. the flight time of switching contact 11, which is strictly proportional to the size of the contact gap (see time interpap tn.ccra6 on

block UBx diagram 3. Fig. H Note (ng-- In this diagram, the frame is 12 and the end 13 is contact .- shown). The measured value tncn, .- is strictly proportional to the size of the inter-cycle gap of the relay under test. because The given travel time of switching contact 11 for all instances of the tested relays is measured at the same (stable) range of the jump of the derivative of the winding current 5, i.e., at the same speed of the relay core.

The value of the time of flight of the switching contact 11 measured by block 3 during operation at a given swing range of the derivative of the current of the winding 5 enters the microcomputer 1 and is stored. The next step in the operation of the device is to calculate the microcomputer 1 coefficient characterizing the flight speed of the switching contact 11 during operation when a nominal operating voltage is applied to the winding 5, according to the formula

Xrab.

frl.C.HOM

tivccTaG.

25

thirty

35 40 45 50 55

where is Xrab. - a coefficient characterizing the flight speed of switching contact 11 during operation when a nominal operating voltage is applied to winding 5;

tn.qHOM the time of flight of switching contact 11 during operation when the rated operating voltage is applied to winding 5;

p.; stub flight time of switching contact 11 during operation when the swing reaches the set value of the derivative from the winding point 5

After that, the microcomputer 1 calculates a coefficient characterizing the flight speed of the switching contact 11 in the process of releasing when the nominal operating voltage is removed from the winding 15, according to the formula

„Tn OHOM

1 mat. - -.

in ccrafi.

where is kotp. coefficient. hlrakk: increasing the speed of flight of the switching contact 11 in the process of releasing upon removal from rated 5 of the rated voltage;

Hp.on time pareno i switching CONTACT 1 1 V Propet ..: -, -, c Gs-LINCH GfI

removing the rated operating voltage from winding 5;

tn.cciaes the time of flight of the switching contact 11 in the process of operation when the amplitude of the jump in the derivative of the winding current 5 reaches a specified value.

After calculating the Xrab coefficient values. and Kotp in microcomputer 1, each of the calculated values of the indicated coefficients is compared with experimentally established corresponding norms depending on the voltage, current, and load inductance of the contacts.

In case of excess coefficient Xrab. relevant norm, i.e. in the case of dangerously slow motion of the switching contact 11, which can cause a long electric arc on the opening contact 12 of the tested relay, leading to contact erosion and relay failures, the microcomputer 1 displays information on the insufficient wear resistance of the making contact 12 of the tested relay. Similarly, if the coefficient is exceeded, K0tp. established norms, i.e. in the case of dangerously slow motion of the switching contact 11, which can cause a prolonged electric arc on the making contact 13, the microcomputer 1 displays on the display screen information about the insufficient wear resistance of the making contact 13 of the tested relay.

In addition, when checking each instance of the relay, information is provided both on the display screen and in the form of a machine printout of the measured Xsrab values. and Kotp, which allows one to judge the margin of wear resistance of each of the contacts at each of the relay instances.

Microcomputer 1 is also carried out according to an appropriate algorithm for statistical processing of accumulated data, which makes it possible to judge the average wear resistance of all batches of tested relays.

Example. The wear resistance of microminiature sealed relays of type RES 49 was monitored. Resistor 6 was selected with a resistance of 3% of the nominal resistance of the relay coil 5. Differentiating device 7 was performed on an RC circuit with parameters 0 022 μf and 430 cm. The peak-to-peak value of the derivative of the winding current was set at the output of the differentiating circuit at 4 mV with an error of ± 2%. As a relay with insufficient wear-resistant C1 contact, you are

also instances in which Кгр 6 5 0.9, and as a relay with insufficient wear resistance of the make contact, such instances appeared in which К0щ 2: 1.7.

After the described sorting, the relay instances, both recognized as not having sufficient wear resistance, and recognized as having sufficient wear resistance, were tested,

0 during which the opening and closing contact data of the relay switched the active load when the DC voltage at open contacts 150 V and current through closed contacts 0.1

5 A. All tested relays worked on 100 x 103 switching cycles (i.e., they performed 100 x 103 switching on and off of the load).

Relays recognized as not having sufficient wear resistance of the make contact after 40 x 103 ... 50 x 103 switching cycles gave failures in the form of non-opening of the make contact when released.

5 In addition, relays recognized as not having sufficient wear resistance of the NC contact were tested during which the above load (150 V; 0.1 A) was switched

0 only break contacts. During these tests, after 70 x 103 switching cycles, failures were detected in the form of an open-circuit opening contacts.

5 Control of the wear resistance of the electromagnetic relay by determining the relationship between the flight time of the switching contact when feeding or removing the rated operating voltage from the winding

0 voltage and time of flight for a given range of the jump in the derivative of the winding current during operation provides the proposed method with the ability to reject all relay instances with an unacceptably low switching speed, the contact in the gap, which causes failure, without breaking and deterioration of the relay and during insignificant time of 10 ... 20 switching cycles (about 0.5 ... 1 s). Thus, non-destructive predictive control of the wear resistance of electromagnetic relays by the proposed method allows to create high-performance

5 automatic devices that provide in the conditions of production a 100% check of the total number of manufactured relays and obtain reliable data on the wear resistance of each particular

Claims (1)

instances of tested relays, as well as averaged over the entire output volume. Claims A method of non-destructive predictive control of the wear resistance of an electromagnetic relay, in which a rectangular voltage pulse is supplied to the winding whose amplitude corresponds to the rated operating value for a relay of this type and the duration of which exceeds the maximum the possible response time for this type of relay, and the time of switching contact switching during operation and the time of switching contact act when released, characterized tem.chto. in order to increase the reliability of control, the time of switching the switching contact during operation is measured from the moment of the first breaking of the NC circuit to the moment of the first closing of the circuit of the closing contact, the time of flight of the switching contact when releasing is measured from the moment of the first breaking of the circuit of the making contact to the moment of the first closing of the circuit opening contact, the measured values of the flight times when triggered and released remember, again fed to the winding rectangular voltage pulses of length By exceeding the maximum possible response time for a given type of relay, the amplitude of which is steadily increasing, starting from the value corresponding to the minimum possible value of the switching voltage for this type of relay, a signal proportional to the relay coil current is generated for each operation, and differentiate, stop the increase in the amplitude of the voltage pulses supplied to the relay winding after, during the next actuation of the relay during stopping, the jump amplitude of the received decree by differentiating the derivative of the winding current from one polarity to the opposite polarity, it will reach a predetermined value pre-set for this type of relay; when the amplitude of the derivative of the winding current reaches a predetermined magnitude, a step is measured and the switching time of the switching contact during operation is measured and stored as the time the moment of the first break of the circuit of the NC contact until the moment of the first circuit of the circuit of the NO contact, a coefficient is calculated that characterizes the flight speed of the switching contact in the actuation process when applied to winding the nominal working voltage according to the formula Xrab tn CHOM t "; steV where Xrab is a coefficient characterizing the flight speed of the switching contact during operation when a nominal operating voltage is applied to the winding; clearly, the flight time of the switching contact during operation when a nominal operating voltage is applied to the winding; tn-stub the time of flight of the switching contact during operation when the amplitude of the jump in the derivative of the winding current reaches a specified value; a coefficient characterizing the flight speed of the switching contact during the release process when the rated operating voltage is removed from the winding, according to the formula thirty matp N oh oh p.sstab. where Kotp is a coefficient characterizing the speed of the switching contact during the release during removal from the winding of the rated operating voltage, tn QHOM is the flight time of the switching contact during release during removal from the winding of the nominal operating voltage voltage; In time, the trip time of the switching contact during operation when the amplitude of the jump in the derivative of the winding current reaches a predetermined value. as a relay with reduced wear resistance of the opening contact, one is recognized for which the calculated value of the coefficient Ksrab. exceeds the value previously set for the relay of this type, and as a relay with reduced wear resistance of the make contact, one is recognized for which the calculated value of the coefficient K0tp exceeds the value previously set for the relay of this type. Hh1 8. UO&M Zm c / 3 a fa t / 0x. 6 / 7.3  t SGI # 0 ## & Ј /  / azmsgh c / rwfct rig.Z