JPS6322539Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention relates to an insulation/continuity testing device that simultaneously detects disconnections and insulation defects in insulated wires and cables using a single device. be.

[Conventional technology]

Conventionally, disconnections in insulated wires and cables have been tested using a continuity tester, and poor insulation has been tested using a DC high-voltage insulation tester, with each connection being changed. In addition, for cords with plugs that are produced in large quantities, such as cords with plugs attached to the ends of rubber or vinyl insulated wires used in various household appliances, etc., tests are conducted on cords that are produced in large quantities. To increase efficiency, a cord tester as shown in FIG. 1 is used.

This device consists of a continuity tester consisting of a high frequency generation circuit 1 and a continuity failure detection circuit 2, and an insulation tester consisting of a DC high voltage generation circuit 3 of, for example, 500V or 1000V, and an insulation failure detection circuit 4. and a switch 5 that automatically switches and connects contacts A and B alternately every second, for example, and a test terminal 8, Connect 8′,
Spot welds 9 at the base of plug blades 7, 7',
Both continuity and insulation tests are carried out from 9' to the tip of a cord 10 having a length of, for example, 2 m (at which the conductive wires 11 are separated from each other).

[Problem that the invention attempts to solve]

However, as mentioned above, the conventional device described above simply switches between two testers with different measurement principles, and requires a certain amount of time (for example, 1 second each) for the insulation test and the continuity test, and also The problem is that it takes more time to read values correctly.

In addition, in continuity tests for cords with plugs,
Even if a disconnection occurs, if the disconnection point is in contact, each tester will not be able to detect it, so after inserting and fixing the plug blades 7, 7' into the test terminals 8, 8'. , code 10 in the vertical direction (arrow
It is necessary to test while bending in the A', B' directions). However, even in the continuity test with this bending action, suppose that when the cord 10 is bent in the B' direction at the plug outlet 12, the welded part 9' comes off, and at this time, the contact of the switch 5 is If it is on the B side, high frequency generation circuit 1
The continuity tester consisting of the circuit 2 and the continuity failure detection circuit 2 cannot detect continuity failure. On the other hand, code 1
0 in the A' direction, and when the disconnected part of the welded part 9' returns to contact with the plug blade 7, the switch 5
If the contact switches to the A side, code 1
Even if an insulation failure occurs within the insulation tester 0, the insulation tester comprising the DC high voltage generation circuit 3 and the insulation failure detection circuit 4 cannot detect it. That is, if the switching period of the switching device 5 and the bending period at the plug outlet 12 are reversely synchronized, a correct pass/fail judgment cannot be made and there is a problem that defective products may be overlooked.

This invention was made in view of the above-mentioned current situation, and was made in an attempt to solve the above-mentioned problems of conventional electric wire insulation/continuity testing devices.

[Means for solving problems]

In this invention, as a means to solve the above-mentioned problems, an electric wire continuity/insulation testing device is constructed as follows. That is, the electrical wire continuity/insulation test device according to this invention applies a high-frequency pulse voltage between opposing conductors of the insulated wire to be tested, and measures the change in capacitance between the conductors due to the poor continuity by changing the high-frequency pulse width. A continuity test circuit section that detects changes and an insulation test circuit section that applies a DC high voltage to the insulator of the wire and detects insulation defects based on the leakage current are coupled via a capacitor on the input side. At the same time, the main feature is that a circuit is provided on the output side to simultaneously display the conductivity and insulation quality of the electric wire.

[Effect]

In the electrical wire continuity/insulation test device configured as described above, the continuity test circuit section and the insulation test circuit section are coupled via capacitors on the respective input sides, so that the relative orientation of the insulated wire under test is While applying a high frequency pulse voltage between the conductors,
Even if a high DC voltage is applied to the insulator of the insulated wire to be tested, the high DC voltage only charges the capacitor and has no effect on the operation of the continuity test circuit. In this case, the waveform of the voltage applied to the insulator of the insulated wire to be tested is a superposition of the DC high voltage and high frequency pulse voltage applied to the insulator of the insulated wire to be tested. Then, the continuity test circuit section detects a change in the sum of the interconductor capacitance and the capacitance of the capacitor, and thus a change in the interconductor capacitance due to poor continuity as a change in the high frequency pulse width. Furthermore, the insulation test circuit section detects an insulation defect in the insulator based on leakage current when the above-mentioned superimposed DC high voltage is applied to the insulator of the insulated wire to be tested. Judgments of continuity and insulation of the insulated wire to be tested are simultaneously displayed by circuits provided on the output sides of the continuity test circuit section and the insulation test circuit section. In this way, both continuity and insulation tests can be carried out simultaneously and quickly, and the bending test of the plugged cord can also be carried out for one cycle while energized.

〔Example〕

Hereinafter, preferred embodiments of this invention will be described with reference to the drawings.

Fig. 2 is a block diagram showing the schematic configuration of a continuity/insulation testing device that is an embodiment of this invention, Fig. 3 is a circuit diagram for explaining the operation of the input section of the device, and Fig. 4 is the device. FIG. 3 is a front view of the operation panel of FIG. In FIGS. 2 and 3, the same reference numerals indicate the same members.

First, the configuration of the continuity test circuit section (high frequency circuit section) and the continuity test performed using it will be explained. As shown in FIG. 3, the insulated wire 10 to be tested is
For example, a two-core vinyl cord with a cross-sectional area of 0.75 mm ² and a length of 2 m with a plug is used, and the pair of plug blades 7 and 7' of the insulated wire 10 to be tested are connected to the test terminal 21A,
Connect to 21B. Conductor 1 of the insulated wire 10 to be tested
If the line capacitance of lines 1 and 11 is (Cx), and the capacitance of the circuit coupling capacitor 22 is (Co),
The composite capacitance (Ca) with respect to the time constant (τ) of the monostable circuit 24 is ca=Cx·Co/Cx+Co. This insulated wire 10 to be tested is now temporarily located at the welded part 9 in the plug 6.
9', the above line capacitance (Cx) is only the plug internal capacitance (Cx') (Cx'<Cx), so the above combined capacitance is Ca ′=Cx′・Co/Cx′+Co. This change is almost the same even if the wire breakage is at a location other than the welded portions 9, 9'. The amount of change in this capacitance (ΔCa=
Ca−Ca′) is the product (ΔCa・Ro) of the circuit coupling capacitor 22 and the parallel resistance (Ro), and a monostable circuit configured by, for example, a C-MOS OR circuit 24A and a NAND circuit 24B Decrease the time constant (τ) of the circuit (monostable multivibrator) 24 and increase the pulse width (tw) of its output pulse (Po)
Narrow down. As shown in FIG. 2, the monostable circuit 24 receives a signal from the high frequency oscillation circuit 23,
A 100KHz square wave pulse (Pt) is constantly input as a trigger, and the monostable circuit 24 outputs an output pulse (Po) with a pulse width (tw) every period (T).
As in this example, the oscillation frequency is 100KHz, which is about 10KHz, compared to 10KHz of the conventional device.
The detection sensitivity for capacitance changes is also high, and disconnection can be detected even when the cord length (L) is about 0.3 m. The output pulse (Po) is input to the integrating circuit 25, which will be explained later. As shown in FIG. 3, the test terminals 21A and 21B have insulation failure detection circuits 26.
DC high voltage generation circuit 27, for example, DC500V
The (+) side of the voltage is always applied, but it only charges the circuit coupling capacitor 22 and does not affect the operation of the high frequency circuit section including the monostable circuit 24 mentioned above. This circuit coupling capacitor 2
One of the features of this device is that it combines two circuits with independent functions for detecting continuity defects and insulation defects. Note that although the reverse voltage diode 28 is inserted just in case, it may be omitted. Further, the diode 29 allows the leakage current (iR) flowing through the insulator of the insulated wire 10 to be tested to pass therethrough, and also serves to prevent backflow.

Further, as shown in FIG. 2, the integrating circuit 25 in the high-frequency circuit section integrates the voltage of the pulse waveform of the pulse (Po) that is its input, and the duty ratio (tw) that changes depending on the pulse width (tw). /T) is output to the comparator circuit 30. This comparison circuit 30 is an IC comparison amplifier, and its reference side terminal has a reference voltage corresponding to the above-mentioned composite capacitance (Ca) when continuity is normal, which is determined by the type and length of the insulated wire 10 to be tested. (Va) is preset. Therefore, the output of the comparison circuit 30 is (ΔVa = Va - Va'), and when this is input to the continuity judgment signal circuit 32, if the continuity is normal, the relay of the continuity judgment signal circuit 32 is
The relay is turned on and sends a "good" signal to the pass/fail judgment display circuit 33, and in the case of poor continuity, the relay remains OFF and sends a "bad" signal. The pass/fail judgment display circuit 33 is provided with an operation delay type photoelectric switch, and the switch is activated after a certain period of time has elapsed, for example, one second after the plug 6 of the insulated wire 10 to be tested is inserted into the test terminals 21A and 21B. is activated, and the poor continuity indicator light 48 or the pass indicator light 50 shown in Fig. 4 is activated.
lights up, and if there is a defect, a buzzer 47 further issues an alarm. These continuity judgment signal circuits 32
The sequence relay circuit of the pass/fail judgment display circuit 33 is omitted from illustration.

Next, the insulation test circuit section (DC high voltage circuit section)
This section explains the configuration of the system and its insulation test. As mentioned above, the test terminals 21A and 21B
When the plug 6 of the insulated wire 10 to be tested is connected to
DC500V from the DC high voltage generation circuit 27 is applied to the insulator of the insulated wire 10 to be tested, and this applied voltage (Eg)
The waveform is a 100KHz square wave superimposed on 500V DC. The insulation resistance detection circuit 34 is composed of an IC amplifier, converts the leakage current flowing through the insulator into a voltage (Vg), and outputs the voltage (Vg) to the comparison circuit 35. This comparison circuit 35 is also similar to the comparison circuit 30 described above.
This is an IC comparison amplifier, and the output voltage (Vgo) of a reference resistance setting section 36 that presets a reference value of insulation resistance is input to its reference side terminal. Therefore, the comparator circuit 35 outputs (Vg - Vgo = ΔVg) to the insulation quality determination signal circuit 37, and this insulation quality determination signal circuit 37 uses a relay signal similarly to the continuity quality determination signal circuit 32. The quality of the insulation is transmitted to the quality determination display circuit 33. In the case of poor insulation, the poor insulation indicator light 49 in Fig. 4 lights up and the buzzer 47 issues an alarm, and in the case of good insulation, the pass indicator light 50 (common for continuity and insulation) lights up. do. These operations are performed in the same manner as in the continuity test described above, so the test is completed, for example, one second after the plug 6 is inserted into the test terminals 21A, 21B.

Next, as shown in Fig. 4, the operation panel 2 of this device is
0 will be explained. The power indicator light 41 lights up when the power switch 46 is turned on to indicate test preparation.
The insulation resistance indicator 42 stably indicates the insulation resistance value (MΩ) of the insulated wire to be tested. The insulation resistance reference value adjuster 43 is used for setting the reference resistance setting section 36 . The other indicator 45 indicates the current corresponding to the output voltage [ΔVa] of the comparison circuit 30 (see FIG. 2) on the continuity test section side,
Settings on the setter 44 of the reference voltage setting section 31 are performed while observing the instructions on the indicator 45. That is,
Using an insulated wire to be tested with normal continuity, the instructions are first set to a predetermined value, and then a continuity test is performed on the unknown circular wire to be tested. Continuity failure indicator light 4 mentioned above
8 is red, poor insulation indicator light 49 is orange, pass indicator light 5
0 is color coded with green. (+), (-)
The terminal 51 is the test terminal 21A, 21B in FIG.
(Although not shown, this is a connector into which the plug of the insulated wire to be tested can be inserted, and is equipped with a light-emitting/light-receiving element that optically detects the insertion of the plug).

The above is a description of the configuration and operation of the device according to one embodiment of this invention, but the scope of this invention is not limited by the above description and the contents of the drawings.
Various modifications may be included without departing from the gist. For example, monostable circuits with various configurations can be used, and insulation failure detection circuits are not limited to DC500V, but can be made with any DC voltage.

[Effect of idea]

Since this invention is constructed and operates as described above, it solves the problems in conventional electric wire continuity/insulation testing devices. That is, there is no need for a movable mechanism, and the structure can be reduced in size with a simple structure. Both continuity and insulation tests can be performed simultaneously and quickly, greatly contributing to improving the efficiency of inspection work. Moreover, the bending test of the cord with a plug only needs to be carried out for one cycle while the power is on, which makes it possible to reliably detect conductive defects.
Reliability in testing can be increased.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a conventional continuity/insulation testing device for insulated cords with plugs, Fig. 2 is a block diagram showing a schematic structure of a continuity/insulation testing device that is an embodiment of this invention, and Fig. 3 A circuit diagram for explaining the operation of the input section of the device, and FIG. 4 is a front view showing an example of the operation panel of the device. 6...Plug, 7, 7'...Plug blade, 9,
9'... Welded part between plug blade and conductor wire, 10...
...Test insulated wire, 11...Electric wire, 21A, 21B
...Test terminal, 22...Circuit coupling capacitor, 2
3... High frequency oscillation circuit, 24... Monostable circuit, 2
5...Integrator circuit, 26...Insulation defect detection circuit, 2
7...DC high voltage generation circuit, 30...Comparison circuit,
31... Reference voltage generation section, 32... Continuity quality determination signal circuit, 33... Quality determination display circuit, 34...
Insulation resistance detection circuit, 35... Comparison circuit, 36...
Reference resistance setting section, 37...Insulation quality determination signal circuit.

Claims (1)

[Claims for Utility Model Registration] 1. Continuity in which a high-frequency pulse voltage is applied between opposing conductors of an insulated wire to be tested, and changes in inter-conductor capacitance due to poor continuity are detected as changes in the high-frequency pulse width. The test circuit section and the insulation test circuit section, which applies a DC high voltage to the insulator of the electric wire and detects an insulation defect based on the leakage current, are connected via a capacitor on the input side, and the output An electric wire continuity/insulation testing device, characterized in that a circuit is provided on the side to simultaneously display continuity and insulation quality determination of the electric wire. 2 The continuity test circuit unit that detects continuity defects inputs a high-frequency pulse oscillation circuit and the pulse of this high-frequency pulse oscillation circuit as a trigger, and measures the pulse width according to the change in capacitance due to continuity defects in the insulated wire to be tested. A monostable circuit that outputs pulses, a comparison circuit that integrates the output pulse voltage from this monostable circuit and compares it with a preset reference voltage, and a signal from this comparison result to a common continuity/insulation pass/fail judgment display circuit. Claim 1 for Utility Model Registration Consisting of a Continuity Judgment Signal Circuit That Outputs
Continuity/insulation testing equipment for electric wires as described in Section 1.