JP4794499B2 - Overcurrent tester - Google Patents

Description

  The present invention relates to an overcurrent tester for testing a device that operates according to a current (overcurrent) exceeding a rating and a flowing time, such as a circuit breaker for wiring.

  A conventional technique for generating an overcurrent for testing a circuit breaker for wiring will be described with reference to FIGS. FIG. 5 is a test configuration diagram according to the prior art, and FIG. 6 is a flowchart showing the test procedure.

  In FIG. 5, an overcurrent tester 1 for testing a device under test 20 such as a circuit breaker includes a transformer 2X for inputting AC 100V of a power source, a slidac 2 and an ammeter 5.

  First, as an initial setting, the examiner rotates the slider 2 while looking at the ammeter 5 to adjust the current supplied to the device under test 20 to a desired value (S301). Thereafter, the test is started, but the internal resistance generates heat due to the current flowing through the wiring 30 and the device under test 20, and the resistance value increases (S302). Therefore, the current decreases relatively (S303). The tester knows the decrease in the current value by reading the value of the ammeter, and adjusts the rotation of the slidac 2 to obtain the desired current value (S304). The tester advances the overcurrent operation test of the device under test 20 while performing the adjustment work accompanying the fluctuation of the current value as needed (S305).

  As described above, in the conventional test method, the tester had to manually adjust the slidac at all times while monitoring the current during the test, which was difficult to adjust and was very inefficient.

  On the other hand, as a conventional technique for automatically controlling a voltage, a technique for an automatic voltage regulator for automatically controlling a transformer with a tap switch for making an output voltage variable has been proposed. For example, in Patent Document 1, it is easy to control a remote control device in a step-type automatic voltage regulator that is installed in the middle of a distribution line of a power system and automatically raises a reduced voltage to the original specified voltage. A technique for transmitting measured values of various voltages has been proposed. Patent Document 2 proposes a technique for preventing a hunting phenomenon in which the voltage fluctuates depending on the state of the load and the tap is repeatedly raised and lowered when the transformer with tap switching is automatically adjusted and controlled.

  In addition, the current control method is a method for generating a constant overcurrent in order to test devices that operate with overcurrent, such as a circuit breaker for wiring, in which the connected wiring and resistance value in the device change due to heat generated by the test current. There is a technology. As another technique for keeping the current constant, there is a voltage control technique in which a transformer such as a slidac that can adjust the voltage is used as a test power supply and a person adjusts while monitoring the current value.

However, each of the above-mentioned patent documents is a technique for automatically adjusting a voltage, not a technique for adjusting a current. In general, the constant current control method is complicated and expensive.
Japanese Patent Laid-Open No. 10-117438 JP 2004-173384 A

  The present invention has been made in view of the above-described circumstances, and provides an overcurrent tester that can efficiently perform an operation test of an apparatus that operates with an overcurrent such as a circuit breaker and can be realized at low cost. The purpose is to do.

  In order to achieve the above object, an overcurrent tester according to the present invention is an overcurrent tester for testing a device under test such as a circuit breaker that opens at a current value, and has an operation means for adjusting a voltage. A voltage adjusting means (slidable) that outputs a voltage according to the rotation of the operating means, a rotation driving means (servo motor) that is attached to the operating means of the voltage adjusting means and rotates the operating means, Current measurement means (current transformer, etc.) that measures the current from the output of the voltage adjustment means to the device under test, the current setting value and the output value of the current measurement means are input, and rotation is based on both values. And adjusting control means for performing feedback loop control for changing the output of the voltage adjusting means by controlling the driving means.

  In the present invention, although the wiring to the device under test and the resistance value of the device under test change due to heat generated by the flowing current, the overcurrent tester performs feedback loop control of the voltage applied to the device under test such as a circuit breaker. Can be automatically adjusted to keep the current constant.

  The adjustment control means of the overcurrent tester according to the present invention includes an initial current value setting means for adjusting a current flowing through the device under test, and a set value input for storing a current value adjusted to a predetermined value as a set value. Means, a set value reset means for resetting the set value, a processing means for comparing the output value of the current measuring means with the set value and calculating the control amount of the voltage adjusting means in accordance with the difference between the two values. And a drive control means for controlling the rotation drive means based on a control amount that is a calculation result of the processing means.

  In the present invention, it is assumed that the adjustment control means is equipped with a microprocessor or the like, and an initial setting operation or a current equivalent to the current flowing through the device under test is input, and feedback processing is performed to perform output for controlling the rotation drive means. An overcurrent tester can be realized and handled.

  The overcurrent tester according to the present invention is further connected in parallel to one or more devices under test connected in series from the output of the adjustment control means to detect the open operation of each device under test and open the circuit. The adjustment control means inputs a state signal indicating the open / closed state of the circuit breaker as a device under test by the operation detection means or the current measurement means, It is characterized by comprising time measuring means (clock function) for measuring the operating time of the tester and display means for lighting when the operating time is within a specified value.

  In the test using the overcurrent tester of the present invention, a constant overcurrent is passed, and the operation time until operation is measured by the operation detection means or current measurement means, and the test is performed depending on whether the operation time is within a predetermined value range. This can be done automatically depending on whether or not the indicator that indicates the quality of the indicator is lit. In the present invention, there is no auxiliary contact indicating the operation, and the operation of the device under test is detected for a plurality of devices under test that open the test circuit when operated, and the test circuit is maintained without being opened. This makes it possible to test multiple devices under test at the same time with a single overcurrent tester.

  The overcurrent tester according to the present invention further comprises means for recording the current applied to the device under test and the operation time, and means for outputting the recorded information as a test result table or the like. To do.

  In the present invention, an automatic test of the device under test is performed, and the test result table as a result can be automatically recorded and output as paper or electronic information, thereby improving the test efficiency.

  The test method according to the present invention is an overcurrent test method using an overcurrent tester, which is initialized by operating the set value resetting means of the adjustment control means in the manual mode before starting the test. The current value flowing through the device under test is adjusted to a desired value by the value setting means, and the input value from the current value detection means at this time is stored in the processing means by operating the setting value input means, and then the test is started. It is characterized by that.

  In the present invention, this test procedure allows an overcurrent test to be easily performed without error.

  ADVANTAGE OF THE INVENTION According to this invention, the electric current supplied to the apparatus which operate | moves with overcurrents, such as a circuit breaker for wiring, can be adjusted efficiently efficiently. Moreover, since voltage adjusting means such as a slidac used conventionally can be used effectively, it can be constructed at low cost.

Embodiments of the present invention will be described below.
(First embodiment)
FIG. 1 is an apparatus configuration diagram of an overcurrent tester according to a first embodiment of the present invention.

  In this figure, an overcurrent tester 1 includes a voltage adjusting means (hereinafter referred to as “slidac”) having a transformer 2X that is insulated and stepped down from an AC 100V power source and an operating means 2a that adjusts the stepped down voltage by rotating it. 2), a device under test 20 such as a circuit breaker for wiring, an ammeter 5 that is inserted into the wiring 30 between the slidack 2 and the device under test and visually checks the current value, and a current proportional to the current value. It comprises current measuring means 4 for output, rotation drive means (hereinafter referred to as “servo motor”) 3 connected to the operation means 2 a of the slidac 2 and rotating, and adjustment control means 10. This adjustment control means 10 includes a processing means 11 such as a sequencer having an arithmetic processing function such as a microprocessor, and a current value detection for converting the current from the current measuring means 4 into a voltage Vm and passing it to the processing means 11. From the circuit 12, the servo motor control circuit 13 for driving and controlling the servo motor 3, the initial current value setting circuit 14 such as an up / down switch or volume for setting the current value to be passed through the device under test 20, and the current value detection circuit 12 A set value input circuit 15 such as a set button for storing the set voltage Vm of the current converted value and a set value reset circuit 16 such as a reset button for resetting the set value.

  Next, the operation of the overcurrent tester 1 will be described using the configuration diagram of FIG. 1 and the flowchart of FIG. First, the function and operation of the adjustment control means 10 will be described.

  As a test mode for performing an overcurrent test, there are a manual mode for performing initial setting and an automatic mode for performing a test after setting.

(Manual mode)
In the manual mode, a tester sets a desired current value as an initial value while looking at the ammeter 5. The processing means (sequencer) 11 of the adjustment control means 10 is basically reset in advance by the set value reset circuit 16 (S111), and the voltage of the slidac 2 is in the zero value position without output. It has become. In this state, the tester operates the raising / lowering switch or volume of the initial current value setting circuit 14 in a direction to increase the current value A applied to the device under test 20 (S101).

  The processing means 11 recognizes this operation and rotates the servo motor 3 to the right (in the upward direction) via the servo motor control circuit 13 to rotate the operation means 2a of the slidac 2 to increase the voltage V. . The tester monitors this current A with the ammeter 5 and performs the raising operation of the initial current value setting circuit 14 until a desired value (for example, 100 A) is obtained.

  The tester stops the raising operation when the desired current value is reached. Thereby, the operation of the servo motor 3 is stopped (S102). Next, a converted value Vm (for example, 5 V) of the current value flowing through the setting value input circuit 15 is output from the current value detection circuit 12 to the processing means 11 (S103), and the processing means 11 The input value is stored (S104). In the automatic mode, the test is started from this state.

(auto mode)
When a test current (example 100A) is applied to the device under test 20, the resistance of the electric wire 30, the contact resistance of the connection terminal, the resistance value of the device under test 20, etc. increase due to heat generation, and the current value is Decrease to 98A. Due to this decrease, the value Vm of the current value detection circuit 12 that outputs DC5V at 100A described above becomes 4.9V (S107). For this reason, since the processing means 11 is smaller than the stored value of 5V, the operating means 2a of the slidac 2 is connected to the current value, i. A command for increasing the output voltage V is issued (S108). When the servo motor control circuit 13 receives this command, it outputs angle information corresponding to the voltage deviation to the servo motor 3 to control the clockwise rotation in the increasing direction (S109).

  As a result, the output voltage of the slidac 2 increases and the current flowing through the test wiring 30 also increases. The servo motor 3 operates until the voltage Vm of the current value detection circuit 12 reaches 5V. Although this operation may cause a hunting phenomenon that is a minute vertical fluctuation of the voltage V, the current of 100 A is continuously maintained stably by a measure such as providing a dead zone, and continues to flow through the device under test 20. (S110). When the test is completed, the tester operates the set value reset circuit 16 to return the overcurrent tester 1 to the initial state (S111). The tester repeats this test operation for a new device under test (S112).

Next, another embodiment of the control procedure of the processing means 11 will be described.
In the present embodiment, as the initial setting in the manual mode, the value Vm from the current value detection circuit 12 when the set value Vs from the initial current value setting circuit 14 becomes a specified current value is set in the set value input circuit 15. Rather than storing it by operation, the setting value Vs of the initial current value setting circuit 14 is maintained in that state, and the processing means 11 constantly compares the converted current value Vm from the current value detection circuit 12 to the automatic mode described above. The feedback control for raising and lowering the output voltage of the slidac 2 is performed in the same procedure.

  As described above, according to the present embodiment, in a test in which a constant current (overcurrent) such as a circuit breaker is continuously supplied, a robust and inexpensive slidac, a servo motor that performs its rotation operation, and a simple feedback loop are assembled. However, the automatic adjustment control circuit makes it possible to carry out an automatic test regardless of the resistance value change due to the flowing current.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. FIG. 3 is an apparatus configuration diagram for simultaneously testing one or two or more devices under test to create a judgment display of the characteristics of the devices under test and a test result table.

  The overcurrent tester 1 includes one or more devices under test 20a to 20n connected in series to the configuration shown in FIG. 1, and motion detection means 6a to 6n connected in parallel to the devices under test 20a to 20n. Signals Sa to Sn representing the operation states of the devices under test 20a to 20n from the respective operation detecting means are input to the processing means 11 of the adjustment control means 10, and the display means 17 for displaying with a lamp or the like from the processing means 11, and a screen And output means 18 for outputting to paper.

  FIG. 4A shows one circuit configuration of the operation detecting means 6a to 6n. The operation detecting means 6 is composed of resistors 61x and 61y connected in parallel to the contact of the device under test 20, and a relay 62 connected in parallel to one of the resistors 61y. The contact of the relay 62 is set as a signal S indicating the opening operation of the device under test.

  Next, the operation of this motion detection means will be described. A constant overcurrent is passed through the plurality of devices under test 6a to 6n in the automatic mode described above. Each of the devices under test performs a self-opening operation after a predetermined time. For example, when the device under test 20a performs an open operation, the contact through which the overcurrent of the device under test 20a has been opened operates, so that the current passes through the resistors 61x, 61y to the other devices under test 20b,. , 20n. For this reason, a voltage appears across the resistor 61y, the relay 62 is operated at this voltage, the relay contact is closed, and the signal Sa is output. At this time, before the operation of the device under test 20a, the resistance was almost zero because the circuit was closed at the contact point. However, the current began to flow through the resistors 61x and 61y, and the current temporarily decreased. However, the current is returned to the original constant current by the feedback control of the adjustment control means 10, and the constant current continues to flow to other devices under test. The processing means 11 inputs this operation signal Sa, determines whether the operation time is good or not, and displays it on the display means 17, and outputs the result determination in the form of a test result table or the like in accordance with the determination of the quality and the test current and operation time. 18 is output.

  Next, another embodiment of the motion detection means 6 is shown in FIG. The operation detecting means 6 is obtained by adding a second relay 63 and a normally closed b-contact reset switch 64 to the configuration of FIG. One circuit is configured to connect the second relay 63 driven by the contact of the relay 62 on the circuit power source Y, Z such as AC100V and hold the reset switch 64 inserted in series when the relay 63 is operated. . The other circuit has a configuration in which the two a contacts of the second relay 63 are connected in parallel to the resistors 61x and 61y.

  With this circuit configuration, when the device under test 20 is opened and the relay 62 is operated, the second relay 63 is operated by the contact and self-holds. The resistors 61x and 61y are bypassed by the contact a of the second relay 63, and are in the same state as the circuit flowing through the contact of the device under test 20a before operation. As a result, current temporarily flows through the resistance until the two relays 62 and 63 are operated, but when the second relay 63 is operated, the state returns to the same state as the original circuit.

  For this reason, when a certain device under test is opened, the overall resistance value increases by the resistance 61x, 61y, and the current is made constant by automatically boosting the slidac 2 by the step-down, but then the resistance 61x, 61y Bypassed and returns to the original test state. For this reason, the voltage from the slidac 2 is temporarily boosted by the resistance, but it is not necessary to increase the voltage so much in normal times. The operation detecting means 6 is initialized by releasing the self-holding of the relay 63 by operating the reset switch 64 after the test is completed.

  As described above, according to the present embodiment, it is possible to simultaneously test a plurality of devices under test while maintaining a constant current with one overcurrent tester, and to determine whether the operating characteristics of the plurality of devices under test are good or bad. The test report can be created automatically.

  INDUSTRIAL APPLICABILITY The present invention can be used for a test of a circuit breaker for wiring that operates with an overcurrent used for a power system or a low-voltage distribution line.

It is an apparatus block diagram of the overcurrent tester by the 1st Embodiment of this invention. It is a flowchart of operation and operation | movement of the overcurrent test device of FIG. It is an apparatus block diagram of the overcurrent tester by the 2nd Embodiment of this invention. It is a circuit diagram of the operation | movement detection means of FIG. It is a circuit block diagram of the conventional overcurrent test. It is a flowchart of the conventional test operation procedure.

Explanation of symbols

1 Overcurrent tester 2 Voltage adjustment means (Slidac)
2a Voltage adjustment operation means 2X transformer 3 Rotation drive means (servo motor)
4 Current measurement means 5 Ammeter 6, 6a, 6b,..., 6n Operation detection means 10 Adjustment control means 11 Processing means 12 Current value detection circuit (means)
13 Servo motor control circuit (means)
14 Initial current value setting circuit (means) (volume)
15 Set value input circuit (means) (set button)
16 Set value reset circuit (means) (reset button)
17 Display means 18 Output means
20, 20a, 20b,..., 20n DUT 30 Test wiring 61x, 61y Resistor 62, 63 Relay 64 Switch

Claims (1)

An overcurrent tester for testing a device under test such as a circuit breaker that opens at a current value,
Voltage adjusting means that has operating means for adjusting the voltage and outputs a voltage according to the rotation of the operating means;
A rotation driving means for attaching to the operating means of the voltage adjusting means and rotating the operating means;
Current measuring means for measuring current from the output of the voltage adjusting means to the device under test;
And having
Initial current value setting means for adjusting the current flowing through the device under test, setting value input means for storing the current value adjusted to a predetermined value as a setting value, and a setting value for resetting the setting value A reset unit, a processing unit that compares the output value of the current measuring unit and the set value, and calculates a control amount of the voltage adjusting unit according to a difference between the two values, and a control amount that is a calculation result of the processing unit An overcurrent tester comprising adjustment control means for performing feedback loop control for changing the output of the voltage adjustment means.
An operation detecting means connected in parallel to each of a plurality of devices under test connected in series from the output of the voltage adjusting means, detecting an opening operation of each device under test, and bypassing the opened circuit; Further, the adjustment control means inputs a status signal of the device under test by the operation detection means or the current measurement means, and measures the operation time of the device under test; and the operation time is defined. Means for determining whether or not the value is within the value .

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