RU1796498C - Device to suppress sparking in electric locomotive current collectors - Google Patents

Abstract

Usage: current collector devices of electric vehicles. SUMMARY OF THE INVENTION 2 there is a load switch, the control inputs of which are connected to the outputs of the formers of on and off signals. The last of them is worn out of threshold blocks, elements NOT, AND, OR. The device also includes a contact monitoring unit between current collectors and a contact wire with a current leakage block, threshold blocks, adders, an AND element, and a voltage presence monitoring unit, as well as a current sensor and a blocking unit of the driver of switching on signals. The sparking of current collectors is eliminated not only in normal but also in emergency modes of an electric locomotive, namely, damage within the traction load, short circuits, overload of power elements, damage to valve units. 1 ill. . SB with

Description

The invention relates to electric collectors of electric vehicles and can be used on contact electric locomotives in the conditions of mines "gas-melted"

The purpose of the invention is to increase reliability.

The drawing shows a block diagram of the proposed device for eliminating sparking of the current collector of an electric locomotive.

The device comprises a controlled switch 1 of traction load 2 and a current sensor 3 in the traction circuit connected in series between the common point of connection of valve blocks 4, 5 in chains

the first group of current collectors 6.7 and a common point of connection of valve blocks 8.9 in the circuits of the second group of current collectors 10, 11. The device also includes a shaper of 12 disconnecting signals, consisting of threshold blocks 13, 14, each of which is connected with its input circuits to current collectors 6, 7, threshold blocks 15,16, each of which is connected with its input circuits to current collectors 10, 11, threshold block 17 connected by its Input to the output of current sensor 3, element NOT 18, actuator 19 at the output connected by your you to one of the managers

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the inputs of the switch 1, the element And 20 connected by its output to the input of the actuating element 19 and the element OR 21 connected by its inputs to the outputs of the threshold blocks 13-17 and the element NOT 18, and the output to one of the inputs of the element And 20. In addition, the device has a driver 22 of the switching signals connected by its output to another control input of the switch 1, a blocking block 23 connected by its input to the output of the driver 12 of the switching signals, and a node 24 for monitoring the contacts between the current collectors 6, 7 and 10, 11 and, respectively Contact wires 25 and 26, respectively. The control unit 24 consists of threshold blocks 27, 28, 29, 30 connected by their input circuits parallel to the valve blocks 4, 5, 8, 9, the current leakage unit 31, and the presence monitoring unit 32 wives whose input circuits are connected between common points of connection of valve blocks 4, 5, 8, 9, summing nodes 33 and 34, connected by their inputs to the outputs of threshold blocks 27, 28, and 29 30, respectively, of threshold blocks 35 and 36 connected by their inputs to the outputs of the summing nodes 33 and 34, respectively, and the element And 3 7 at the output connected by its inputs to the outputs of the threshold blocks 35, 36, and the output to the inputs of the element NOT 18 of the driver 12 of the disconnecting signals and to the input of the driver 22 of the switching signals. In this case, the input of the voltage presence control unit 32 is connected to another input of the And 20 element,

A device for eliminating sparking of current collectors of an electric locomotive operates as follows.

In the initial state, all contact elements of the current collectors 6, 7, 10, 11 are pressed to the contact wires 25.26, the switch 1 of the traction load 2 is turned off. In this case, under the action of the voltage in the contact network through the current leakage unit 31, a small current flows (of the order of 10 MA), which, distributed evenly between the valve units 4, 5, 8, 9, creates almost the same voltage drops across these valve manifolds. Therefore, the threshold blocks 27-30, connected by their input circuits to the corresponding valve blocks, generate the same signals at their outputs, indicating the presence of electrical contact between all current collectors and contact wires. Threshold blocks 27-30 normalize the output signals in magnitude and thereby eliminate their dependence on the voltage in the contact network and on

current values in valve blocks. The output signals of the threshold blocks 27-30 are then summed in the respective summing nodes 33 and 34, whereby the output signals of the blocks 33 and 34 are proportional to the number of current collectors pressed against the corresponding contact wire. The output signals of blocks 33 and 34 are then fed to the inputs of the corresponding threshold blocks 35 and 36, which generate signals at their outputs only when the malicious signal exceeds a certain value. This threshold value is selected in a known manner, based on the minimum number of current collectors pressed against the contact wire, at which the traction current from the contact network is allowed, based on the data presented to the device

reliability requirements. Since in the initial state all the current collectors are pressed to the contact wire, the input signals of blocks 35 and 36 exceed the threshold value and therefore at the outputs

of these blocks, signals are generated which lead to the formation of an output signal of the contact monitoring unit 24 by means of the AND element 37. The output signal of the node 24 is fed to one of the inputs of the shaper

22 switching signals and at the same time, to the input of element 18 is NOT a shaper of switching signals.

At the same time, the voltage between the current collectors b, 7, 10, 11, which

are the differences in the voltage drop across the respective valve blocks, affect the corresponding threshold blocks 13-16. Due to the specific nonlinearity of the volt-ampere characteristic (CVC) of the valve blocks, the input signals of the threshold blocks 13-16 are proportional to the ratio of currents in the circuits of the corresponding valve blocks and depend little on the amount of

contact current network, i.e. practically only characterize the state of current collector contacts affecting the distribution of currents in parallel circuits of current collectors. Indeed, the CVC of a semiconductor

the valve can be approximately described analytically as follows:

(e4ou -1),

where I is the valve current, U is the voltage drop across the valve,

to is the return saturation current (it has a constant value of the order of microamps).

Taking into account that in the proposed device the minimum gate current is of the order of milliamps (with switch 1 off), the analytical expression of the I – V characteristic of the gate in operation can be simplified to the form:

In this case, the voltage between two current collectors, in the circuit of which the same valve blocks are connected (the input signal of one of the threshold blocks 13-16) can be determined approximately from the formula:

.Ul-U2 "

1

40

e

6 2

where Ui, IJ2 is the voltage drop across the valves x, li, 2 are the currents in the valve circuits. The above formula shows the proportional dependence of the signal UBx. on the ratio of currents in parallel branches of current collectors.

Each of the threshold blocks 13-16 under the influence of the input signal UBX. generates a signal at its output, indicating a deterioration of the current collector contacts only when the input signal, and therefore the current ratio in the circuits of the respective current collectors, exceeds a predetermined threshold value. Moreover, the higher reliability requirements are imposed on the device, the lower the threshold value is chosen to increase the degree of lead in the formation of a signal about an unacceptable deterioration of current collector contacts. In the case under consideration, i.e. when all current collectors are pressed to the contact wires and the currents in the parallel circuits of the current collectors are distributed almost uniformly, the signals at the outputs of the threshold blocks 13-16 and at the corresponding inputs of the element OR 2 do not occur. Signals also do not occur at the other inputs of the OR element 21, since there is NOT a signal at the input of the element 18, which means there is no signal at its output, and there is no signal at the output of the threshold unit 17 due to the absence of current in the traction load. Therefore, at the output of the OR element 21, and therefore, there is no signal at the output of the disable signal generator 12, which does not block the operation of the enable signal generator 22 through the block 23. As a result of this, the signal at the output of the contact monitoring unit 24 leads to the formation of the switching signal by the driver 23, after which the switch 1 is turned on and the traction load 2 flows, distributed approximately uniformly in the parallel 5 current collector circuits.

When the collector contacts deteriorate, for example, the contact of the current collector 6 with the contact wire 25, the current distribution in the current collector circuits 0 and 6 begins to change, which leads to the formation of a signal at the output of the corresponding threshold unit 13 and, consequently, to the appearance of a trip signal at the output driver 12 followed by a proactive 5 shutdown of switch 1 of traction load 2. At the same time, the disconnecting signal at the output of driver 12 blocks through the block 23 the operation of driver 22 of the switching signals for some A predetermined time exceeding the time of complete disconnection of the traction load, as well as during the duration of the operation of the tripping signal.

After the circuit breaker 1 is turned off, the shaper 12 remains operational due to the leakage current in block 31, i.e. continues the formation of the tripping signal and thereby blocks the operation of the driver 22 of the switching signals. At 0. complete violation of the current-sensing contact under consideration, the signal at the input of the threshold block 27 disappears, which leads to the disappearance of the signal at the output of the contact monitoring unit 24, due to which, using element 5 of HE 18, a duplicate signal is formed to turn off the switch 1. Upon subsequent separation from contact wire 25 of all other current collectors, sparking is practically eliminated due to 0 disconnected state of circuit breaker 1 and low leakage current.

The subsequent switching on of the switch 1 of the traction load 2 occurs after restoration of the required number of current-tightening contacts in the parallel-connected current collectors in the case of a practically uniform distribution of the leakage current in the current-taking branches, when the output of the shaper 12 does not have a disconnecting signal blocking the operation of the shaper 22 including signals.

In the case of an excessive increase in current in the traction load, in which damage to the circuit breaker 1 or valve blocks is possible, as well as the dangerous sparking of the current collector contacts due to metal fusion at an increased current density, the output signal of the current sensor 3 becomes larger than the preselected threshold values, as a result of which the threshold block 17 generates a signal at its output, leading to the formation of a disconnecting signal at the output of the driver 12 with the subsequent disconnection of the switch 1. A dangerous increase in the traction current is prevented. The next switching on of the switch 1 occurs automatically when the current in the pulling load 2 decreases to a safe value, if the current-collecting contacts are not broken.

In case of damage to valve manifolds, for example, due to overheating due to high current or electrical breakdown.

The voltage drop on such valve blocks becomes less than the threshold value (equal to almost zero), as a result of which the signal disappears at the outputs of the corresponding threshold blocks 27-30, which excludes the formation of the switching signal and, therefore, the inclusion of the switch 1 traction load 2. Thus the current draw from the contact network is eliminated and the electric locomotive automatically stops. This prevents the formation of false switching signals, as well as a collision with insulating inserts in the contact network and, consequently, the possible sparking of current collector contacts with damaged valve blocks.

In the case of a significant decrease in the voltage in the contact network, below a predetermined threshold value at which false trip signals can be generated by the driver 12, the output signal for the formation of these trip signals disappears at the output of the voltage presence control unit 32. Owing to this, mutual interference and possible self-oscillations are excluded during the simultaneous operation of several such devices when short-term significant voltage drops in the contact network occur at the time of periodical switching-on of switch 1.

Thus, the described device makes it possible to eliminate the sparking of current collectors of an electric locomotive with high reliability without complicating the circuit not only in normal but also in emergency operation of the electric locomotive and the device (in case of damage within the traction load, with short circuits, overload of power elements damage to valve manifolds), as well as the simultaneous operation of several electric locomotives equipped with the proposed device in one section.

Claims (1)

SUMMARY OF THE INVENTION A device for eliminating sparking of electric locomotive current collectors, comprising a switch installed in the traction load circuit in series with two groups of valve units connected in parallel connected to current collectors on corresponding contact wires, a signal driver, the output of which is connected to the first control input of the switch, a shaper of disconnecting signals with two groups of main threshold blocks and an element NOT connected by outputs to the inputs of an OR element, spolnitelnym element connected to the output of the second control input of the switch; node for monitoring contacts between current collectors and contact wires with a current leakage unit, two groups of normalizing blocks connected by outputs to the inputs of the respective adders, two threshold blocks connected by inputs to the outputs of the respective adders and the AND element, connected by inputs to the outputs of the threshold blocks, and by an output - to the input of the element of the driver of the disconnecting signals and the first input of the driver of the switching signals, lock node connected between the output of the actuating element of the driver of the disconnecting signals and the second input, the driver of the switching signals, a current sensor, characterized in that, with In order to increase the reliability of operation, an And element is included in the driver of the disconnecting signals, included between the output of the OR element and the input of the actuating element, and an additional threshold block included between the output of the current sensor and one of the inputs of the OR element, and the contact control unit between the current collectors and contact wires is a voltage presence control unit connected in parallel with the current leakage unit between the combined terminals of the valve block groups and the output connected to the corresponding input of the element And a shaper disconnecting signals, while the current sensor is installed in the traction circuit, the inputs of the main threshold blocks of the generator of disconnecting signals are connected between pairs of corresponding current collectors, and the inputs of the normalizing blocks of the contact control node between the current collectors and contact wires - between the power terminals of the corresponding valve blocks.