SU1267504A2 - Device for checking contacts of relays - Google Patents

Abstract

The invention relates to instrumentation and can be used for accelerated testing of relay contacts. The invention is additional to izob (L NJ

Description

retention no a. with. No. 1163381. The purpose of the invention is to reduce the time that the contacts of the relay are tested with a current less than, where is the current of moving the relay. When the relay is turned on, as the current increases, the thrust force that grows along with it will exceed the opposing force, and the measles of the electromagnet will begin to move. If a charge current is applied to the relay winding in some way, which is a little less than the starting current, then when a supply voltage is applied to the relay winding, the relay will operate faster.

those. the response time is reduced because The rise of current to the magnitude of the current of moving will not start from zero, but from the value of looa (recharge current). To ensure this condition, the device for controlling the contacts is additionally equipped with a feed block for the windings of the monitored relays, which is made on the transistor 13 and resistors 14, 13. The charge current is determined by the value of the resistor 15, which is slightly less moving current. The invention makes it possible to reduce the test time of the relay contacts for reliability. 3 il.

The invention relates to instrumentation and can be used for accelerated testing of relay contacts.

The purpose of the invention is to improve the performance of monitoring contacts of a relay by creating a preliminary feed of a relay with a current lower than the current, where Ifnp is the current of moving the relay

FIG. 1 is a functional block diagram of an apparatus for monitoring relay contacts; in fig. 2 is a timing diagram explaining the time dependence of the current in the relay coil as the box moves.

When the relay is turned on, as the current increases, the increasing effort with it will exceed the opposing force, and the measles of the electromagnet will begin to move. The time interval — from the moment when the voltage is applied to the relay coil to the start of the core pushing — is called the pushing time t. The value of the current in the relay coil at which the measles begin to move is called the 1. moving current.

The time required for moving the moving parts of the relay from the moment of moving to closing or opening of the corresponding relay contacts is called the movement time tqg. Thus, the time tj of the relay is

, p

The value of the current in the relay coil at which the relay fully operates is called current 1 ,. triggered.

When testing relays, the relay test speed is mainly determined by the time parameters of the relay: the response time tjp and the release time, since the frequency at which the test is performed is determined by the values of t ,. and, and the tolerance frequency F of the relay is equal to

one

F

+ t.

-sr -t

If in a relay winding, in some way, to feed a current, the charge is slightly less than the starting current, then when a supply voltage is applied to the winding of the relay, the relay will operate faster, i.e. the response time of the relay will decrease (Fig. 3).

This is due to the fact that the increase in current to the magnitude of moving will occur faster, since the increase in current in the relay coil will start

(fig.Z).

not from zero, but from the value of I.

., and ocjjn nnpi -L "for

Due to this, the response time "relay will be reduced by an amount determined by the rise time of the relay operation current from O to the make-up current value, and will be equal to:

+ t.

-tr

wed

The device contains a generator of 1 pulses, a distributor of 2 pulses, a counter 3 of the total number of actuations of the monitored relay, an OR 4 element, which, together with the distributor of 2 pulses, forms a control time program block. In addition, the device contains cells for testing relay contacts, each of which is developed by elements 5 and 6 (by the number of monitored contacts), 7 counters of failures of disconnecting contacts (by the number of disconnecting contacts of the monitored relay), and counters of 8 failures of closing contacts (according to the number of closing contacts of the monitored relay), terminals 9 and 10 for connecting respectively opening and closing contacts of the relay. At the same time, the first inputs of the And 5 elements of all the cells are combined and connected to the output 2.1 of the distributor 2 pulses, and the first inputs of the And 6 elements of the same cells are also combined and connected to one of the inputs of the OR 4 element and to the output 2.3 of the distributor 2. At the same time, each cell of the second input element And 5 is connected to terminal 9 for connecting the expansion contact of the relay with one of the terminals of the first mode resistor. The second input element And in each cell is connected to terminal 10 for connecting the corresponding closing contact and to one of the terminals of the second mode resistor. The second terminals of all the mode resistors of the cells are combined and connected to the first pole of the + E power supply source, which can be used, for example, a DC generator, terminals 11 of all the cells to which the first windings of the respective relays are connected, combined and connected to element output 4. The terminals 12 of all the cells to which the second terminals of the contacts and windings of the monitored relays are connected, are interconnected and connected to the second pole of the power source (to the common bus of the device). If the monitored relay contains more KoliTaKTOB, then the number of elements of AND 5 or AND 6 increases in proportion to the increased number of contacts (depending on the type of contact: opening, closing) and the number of counters 7 or 8 increases accordingly. As the number of controlled relays increases, the number of cells increases to control the relay. In addition, the device contains an additionally inserted transistor 13, the base of which is connected via resistor 14 to output 2.1 of distributor 2 and to one of the inputs of elements AND 5. The collector of transistor 13 through resistor 15 is connected to the first pole of the source + E power, and the emitter is connected to the output of the element OR 4. I The pulse generator 1 is designed to generate pulses at its output. The distributor 2 pulses is designed to distribute the pulses from generator 1 (outputs 2.1, 2.2, 2.3, 2.4) arriving at its input over time 1 as well. Counter 3 is designed to count the total number of actuations of monitored relays during their testing. . Counter 7 is designed to count failures of the opening contacts of the relay, and counters 8 to count the failures of the closing contacts of the monitored relay. In this case, the failure of the opening contact to operate here and hereinafter refers to the state of the device when, when the relay is de-energized, its contact is in the NC state (normally closed), but there is no electrical contact for any reason. And the failure of the operation of the closing contact is understood to be such a state of the device, when, with the relay on, the switching contact switches over, i.e. its HP (normally closed) contact is closed, but there is no electrical contact for any reason, i.e. both in that and in other case disturbances of normal contact are controlled. In this case, the NC contact is controlled in the disconnected state of the relay, and the HP contact is monitored in the switched on state of the relay. Transistor 13 is designed to create a pre-current with Ifioa (Fig. 3) windings of the tested relays. 5 For simplicity, the operation of the device is shown by the example of the operation of a single cell formed by elements 5 and 6, counters 7 and 8, and clamps 1.1 to 12 for connecting contacts and windings of a monitored relay. The remaining cells are similar. The device for controlling the contacts of the relay works as follows. As soon as the first pulse from the generator 1 pulses arrives at the input of the distributor 2, the last activates, and at its output 2.1 a positive signal comes out that goes to one of the inputs of the element AND 5. At the other input of the element AND 5, the signal is not received (logical zero), since the relay contact connected to terminal 9 is in the NC position (contact present), and the entire supply voltage (+ E) of the power drops on the corresponding mode resistor. Due to the fact that only one positive signal is sent to the inputs of the And 5 element, there is no signal at its output and the counter 7 finds c in the initial state. In case the relay contact, connected to terminal 9, is in the NC position, but the electrical contact for some reason has broken, the voltage (+ Е) of the power source will go to the input of the And 5 element, and the other the input element And 5 attached positive signal from the output 2.1. the distributor 2, then at the stroke of the element I 5 through the Wits signal, and the counter 7 will detect one failure of the operation of the break contact of the relay. In this way, a contact relay connected to terminal 9 is checked in the NC position and a contact fault is detected if it occurs. When entering from output 2.1 distributes the bodies 2 positive signal, it also simultaneously enters the bases of the transistor 13 and opens it. The collector-emitter circuit of the transistor 13 begins to flow current (Inoq current make-up), the magnitude of which is determined by the value of resistor 15. This current flows into the windings of the subjects. the relay and its value is selected (due to the choice of the parameter of the resistor 15) is slightly less than the magnitude of the relay moving current (Fig. 3), i.e. I, -. If this condition is fulfilled. Then, if the windings of the tested relays are flowing (. Tr), the relay contacts are in the initial state. When a second pulse arrives at the input of the distributor 2 from generator 1, the distributor 2 triggers a positive signal at its output 2.2, and from output 2.1 the positive signal will disappear (logical zero). At the same time, a positive nocTynnt signal to the input of the element OR 4, and the ac of its output is to terminal 11 for connecting the relay under test. Relay ON. It should be noted that, due to self-induction, the relay coil current does not disappear immediately after removing the pulse from the output 2.1 of the distributor 2. The relay in this case will occur. more quickly, since a recharge current was already flowing through its winding, which was insufficient for moving the relay core. But when the current winding goes to the relay. Adequate to trigger it, the current rise in the relay coil does not occur from zero, but from a value approximately equal to the charging current. Therefore, the increase in the current in the winding to the magnitude of the moving current in this case occurs much faster (Fig. 3). After a time which is now shorter than the response time of the relay without make-up current, its contacts from the NC position (normally closed) transfer to the HP position (normally open), the third pulse from generator 1 again triggers the distributor 2 and at its output 2.3 wits positive signal. This signal through the element OR 4 will continue to keep the monitored relay in the on state and, in addition, a positive signal will be sent to one of the inputs of the element 6. At the same time (similar to the above) two cases are possible. If the relay contact connected to terminal 10 switches to the NC position and forms a normal electrical contact, then the entire supply voltage (+ E) of the power source drops to the corresponding (mode resistor and the second input element And 6 signal is not received. In this case at the output of element 6, the signal does not turn out and the counter 8 will be in the initial state.

If the contact connected to terminal 10 is transferred to the NC position, but there is no electrical contact for any reason, the supply voltage C + E) of the power supply will be applied to the second input of the And 6 element.

In this case, the positive signals at the input of the element And 6 from the power source and from the output 2.3 of the distributor 2 will coincide, which will cause the output of the element 6 of the signal and the counter 8 will record this signal. Under the influence of the fourth pulse from the generator 1, the valve 2 triggers and at its output 2.4 a positive signal is sent that goes to the input of the counter 3 of the total number of actuations of the monitored relay and records one pulse indicating the end of one complete test cycle. After completion of the tests, the total number of tripping cycles of the monitored relay will be recorded in meter 3. The next impulse from generator 1 will cause the appearance of a positive signal at the output 2.1 of the distributor 2 and the whole control process will be repeated in the same way as above.

Thus, after the end of the testing process, the operator will have the quantitative values of the failures of the tripping of the opening and closing contacts of the relay, as well as the total number of triggers of the tested relay.

The data obtained during the test allows, by mathematical processing, to determine the numerical values of the reliability of the switching element.

Usually the process of testing relay contacts for reliability and durability is a very long process. One of the ways to increase the speed of testing a relay is to reduce the response time. In the proposed device (due to the introduction of feeding the relay before supplying the operating voltage to its winding) it became possible (for the device as a whole) to artificially reduce the response time of the relay, and therefore slightly increase the frequency at which the pulse generator 1 operates, which is equivalent to reducing time test relay. At the same time there is no objective loss of information about the operation of the relay.

Claims (1)

Invention Formula Device for monitoring contacts turnips aut. St. No. 1163381, characterized in that, in order to increase the performance of the control, a block is added to feed the windings of the monitored relays, executed on the transistor and two resistors, the first resistor being connected to the base of the specified transistor and the emitter of the specified transistor connected with the output of the element OR, and the collector of the transistor through the second resistor is connected to a DC generator. FIG. 2 i.H