TWI695558B - Cable breakage precursor detection device - Google Patents

Abstract

The cable breakage precursor detection device of the present invention detects the breakage precursor of a cable connected to a heater as a load and flowing current to the heater. The cable contains multiple current paths connected in parallel. The cable breakage precursor detection device includes: a current detection part that detects the current flowing through at least one current path among the plurality of current paths; and an alarm part that compares the detection value of the current detection part with a threshold value The power-on state of each current path, to determine whether there is a disconnection of multiple current paths, and when it is determined that there is a disconnection, an alarm is issued.

Description

Cable breakage precursor detection device

The present invention is related to detecting the disconnection of a cable connected to a load and flowing current to the load.

Conventionally, in a circuit configuration in which a cable is connected to a load and current flows to the load through the cable, if the cable is disconnected, of course, power is not supplied to the load.

For example, in a heating device that heats a certain object to be heated, a cable is connected between a heater as a heat source and a power supply circuit or a control circuit. If such a cable breaks, the heater cannot be controlled, and specific heating cannot be performed.

Therefore, in order to detect the harbinger of the cable, Patent Document 1 discloses a device in which a wire for voltage supply (original wire that is actually needed) is provided on the cable provided in the movable part, and the original Compared with a dummy wire with poor bending resistance, by detecting whether the dummy wire is broken or not, it is predicted that the original wire breakage time is close to or broken. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 5-340985

[Problems to be solved by the invention]

In the device disclosed in Patent Document 1, a special cable with a dummy wire having poor bending resistance needs to be produced, and a versatile cable cannot be used. In addition, since the binary judgment for predicting the original wire breakage is based on whether the dummy wire is broken or not, it is impossible to adjust the sensitivity of the detection cable breakage sign. Also, abnormalities such as load disconnection cannot be detected.

Therefore, the object of the present invention is to provide a device for detecting a broken sign of a cable without a special cable. [Technical means to solve the problem]

As an example of the present disclosure, a cable breakage indication detection device is a device that detects a breakage indication of a cable connected to a load and flows current to the load, and includes a current detection section and an alarm section. The cable contains multiple current paths connected in parallel. The current detection unit detects a current flowing through at least one current path among the plurality of current paths. Furthermore, the alarm unit compares the detection value of the current detection unit with the threshold value, detects the energization state of the multiple current paths, thereby determining whether the multiple current paths are broken, and issues an alarm when it is determined that there is a break.

In this configuration, a dummy cable or the like with poor bending resistance is not necessary, and an ordinary cable can be used. Also, it is not a binary judgment of whether the dummy wire is broken or not, but it detects the current flowing through at least one current path among the multiple current paths and detects the energization status of the multiple current paths based on the comparison with the threshold. It is also possible to adjust the sensitivity of the detection cable breaking sign through the setting of the threshold. Furthermore, abnormalities such as load disconnection can also be detected.

Furthermore, in an example of the present disclosure, the cable breakage warning detection device is a device that detects a breakage warning of a cable connected to a load and flows current to the load, and includes a current detection section and an alarm section. The cable contains multiple current paths connected in parallel. The current detection unit detects the sum or difference of currents flowing through at least two current paths among the plurality of current paths. Furthermore, the alarm unit compares the detection value of the current detection unit with the threshold value, detects the energization state of the multiple current paths, thereby determining whether the multiple current paths are broken, and issues an alarm when it is determined that there is a break.

In this configuration, the energization state of the multiple current paths is detected based on the combination of currents flowing through the multiple current paths, so it is possible to detect the combination of the multiple current paths for disconnection.

In addition, in one example of the present disclosure, the cable breakage precursor detection device is a device that detects the breakage precursors of multiple cables that are respectively connected to a plurality of connection portions of a load and flows current to the load, and is provided with a current detection Department and Alarm Department. The cable includes a first cable connected to the first connection portion of the load, and a second cable connected to the second connection portion of the load. The first cable is composed of multiple first current paths connected in parallel, and the second cable is composed of multiple second current paths connected in parallel. The current detection unit detects the sum or difference between the current flowing through at least one current path among the plurality of first current paths and the current flowing through at least one current path among the plurality of second current paths. Furthermore, the alarm unit compares the detection value of the current detection unit with the threshold value, detects the energization state of the plurality of first current paths and the energization state of the plurality of second current paths, thereby determining the plurality of first current paths and the plurality of first current paths 2 If the current path is disconnected, an alarm is issued when it is judged to be disconnected.

In this configuration, for the first cable and the second cable connected to the load, the energization status of the multiple current paths is detected based on the combination of the currents flowing through the multiple current paths, so the detection of the first cable There is a combination of multiple current paths and multiple current paths of the second cable with or without disconnection.

In addition, in one example of the present disclosure, the cable breakage precursor detection device is a device that detects the breakage precursors of multiple cables that are respectively connected to a plurality of connection portions of a load and flows current to the load, and is provided with a current detection Department and Alarm Department. The cable includes a first cable connected to the first connection portion of the load, and a second cable connected to the second connection portion of the load. The first cable is composed of multiple first current paths connected in parallel, and the second cable is composed of multiple second current paths connected in parallel. The current detection unit detects the sum or difference of the sum or difference of currents flowing through at least one current path in the second current path and currents flowing through at least two current paths in the first current path. Furthermore, the alarm unit compares the detection value of the current detection unit with the threshold value, detects the energization state of the plurality of first current paths and the energization state of the plurality of second current paths, thereby determining the plurality of first current paths and the plurality of first current paths 2 If the current path is disconnected, an alarm is issued when it is judged to be disconnected.

In this configuration, for the first cable and the second cable connected to the load, the energization status of the multiple current paths is detected based on the combination of the currents flowing through the multiple current paths, so the detection of the first cable There is a combination of multiple current paths and multiple current paths of the second cable with or without disconnection.

Furthermore, in an example of the present disclosure, the threshold value is defined based on the detection value of the current detection unit in the initial state.

In this configuration, the wire breakage detection is performed with the amount of change from the initial state, so that the wire breakage omen detection can be performed with a more accurate determination. [Effect of invention]

According to the present invention, no special cable can be used to detect the cable breaking sign.

Hereinafter, a mode for implementing the present invention will be described with reference to several drawings.

∙Application examples First, an example of applying the present invention will be described with reference to FIG. 1. FIG. 1 is a diagram showing the overall configuration of a heating device including a cable breakage detection device according to an embodiment of the present invention.

As shown in FIG. 1, the cable breakage warning detection device 201 of this embodiment is a device that detects the breakage warning of cables 31 and 32 connected to a heater 2 as a load and flowing current to the heater 2 . In the example shown in FIG. 1, the cable 31 includes a plurality of current paths CA11 and CA12 connected in parallel. The cable breakage precursor detection device 201 includes: a current detection unit 4 that detects the current flowing through one of the plurality of current paths CA11 and CA12; and an alarm unit 10 that detects the current detection unit 4 The value is compared with the threshold value to detect the energization state of the multiple current paths CA11 and CA12, thereby determining whether the multiple current paths CA11 and CA12 are disconnected, and when it is determined that there is a disconnection, an alarm is output.

∙Configuration example Next, the configuration of the heating device according to the embodiment of the present invention will be described with reference to the drawings. As described above, FIG. 1 is a diagram showing the overall configuration of a heating device including a cable breakage detection device according to an embodiment of the present invention.

As shown in FIG. 1, the heating device 101 includes a power source 1, a heater 2, cables 31 and 32, a current detection unit 4 and an opening and closing unit 5. The heater 2 corresponds to the "load" of the present invention. The heater 2 is connected to the power source 1 via cables 31 and 32. The cables 31 and 32 are current paths connecting the power supply 1 and the heater 2. In this example, the power supply 1 is a single-phase AC power supply, and the heater 2 is a 2-terminal load. The opening and closing part 5 is inserted in series in the cable 31. In addition, the cable 31 includes two current paths CA11 and CA12. The current detection unit 4 detects the current flowing through the current path CA12. The current detection unit 4 is, for example, a current transformer (current transformer), a resistor is connected to the secondary side, and a voltage proportional to the detection current is output.

The control unit 20 performs the control of the opening and closing unit 5 and the control related to the detection of the disconnection of the cable.

The opening and closing unit 5 is, for example, a solid state switch, and opens and closes based on the output signal of the output unit 16.

The setting part 12 inputs a setting value by manually inputting or communicating from the outside, and stores the value in the memory part 13. The current measurement unit 11 measures the current based on the detection value of the current detection unit 4. The determination unit 14 determines whether it is an abnormal state based on the value stored in the storage unit 13 and the value measured by the current measurement unit 11. When the judging unit 14 judges that it is in an abnormal state, the abnormal output unit 15 issues an alarm by the relay output or the lighting of the indicator, the setting of the communication flag, and so on.

FIG. 2 is a diagram showing the relationship between the current flowing through the first current path CA11, the current flowing through the second current path CA12, and the measurement result of the current detection unit 4 in a disconnected state at a specific location. In FIG. 2, i11 is a current flowing through the first current path CA11, i12 is a current flowing through the second current path CA12, and iCT is a detection value of the current detection unit 4 (measurement value of the current measurement unit 11). In either case, the current flowing through the heater 2 is set to a relative value at 1.0.

When there is no disconnection in any current path, the measured current value is 0.5. When the first current path CA11 is disconnected, the current flowing through the heater 2 flows only through the second current path CA12, so the current flowing through the second current path CA12 becomes 1.0. When the second current path CA12 is disconnected, the measured current value becomes 0. The measured current value also becomes 0 when the heater itself is disconnected.

The setting unit 12 shown in FIG. 1 causes the memory unit 13 to memorize the upper and lower limit values, for example, 0.25 and 0.75. The determination unit 14 uses the value of the storage unit 13 as a threshold, and determines the magnitude relationship between it and the measured current value. Fig. 3 is a graph showing the relationship between the threshold value and the measured current value. If the measured current value is more than 0.25 and less than 0.75, it is regarded as normal. That is, it is determined that the current path is not broken. If the measured current value is 0.75 or more, the first current path CA11 is regarded as broken. In addition, if the measured current value does not reach 0.25, it is regarded that the second current path CA12 is disconnected. That is, this is detected as a sign that the cable 31 is broken.

Furthermore, the measured current value does not reach 0.25 when the heater 2 is disconnected, so in this embodiment, the disconnection of the second current path CA12 and the heater 2 cannot be distinguished.

FIG. 4 is a flowchart showing the processing contents of the control unit 20 shown in FIG. 1. First, reset the current value memory flag to determine the state of the output section (S1®S2). If the state of the output part is on, that is, the switch is on, the measured current value is read (S3). Then, determine and register the threshold based on this value, and set the current value memory flag (S4®S5®S6). In the example shown in FIG. 3, if the initial measured current value is 0.5, the value (0.75, 0.25) obtained by adding and subtracting this value and the relative variation 0.25 is registered as the threshold.

Under normal conditions, the S7®S2®S3®S4®S7 cycle is executed repeatedly. After that, if the measured current value becomes the value in the abnormal range, abnormal output is performed (S7®S8). Furthermore, if the current value memory flag is reset in other routines, the measured current value at that time point is updated as the initial current value.

Secondly, it shows an example of detecting a broken wire sign by detecting current flowing through two current paths.

FIG. 5 is a circuit diagram of a heating device that differs from the heating device shown in FIG. 1 in the configuration of the current path detected by the current detection unit 4. In this example, the current detection unit 4 detects the difference between the currents flowing through the two current paths CA11 and CA12.

6 is a diagram showing the relationship between the current flowing through the first current path CA11, the current flowing through the second current path CA12, and the measurement result of the current detection unit 4 in a disconnected state at a specific location. In FIG. 6, i11 is the current flowing through the first current path CA11, i12 is the current flowing through the second current path CA12, and iCT is the detection value of the current detection unit 4. In either case, the current flowing through the heater 2 is set to a relative value at 1.0.

When there is no disconnection in any current path, the current flowing through the first current path CA11 and the second current path CA12 is 0.5, and the measured current value is 0. When the first current path CA11 is disconnected, the current flowing through the heater 2 flows only through the second current path CA12, so the current flowing through the second current path CA12 becomes 1.0 and the measured current value becomes 1.0. When the second current path CA12 is disconnected, the current flowing through the heater 2 flows only through the first current path CA11, so the current flowing through the first current path CA11 becomes 1.0 and the measured current value becomes -1.0. When the heater itself is disconnected, the measured current value becomes zero.

In the example shown in FIG. 5, the setting unit 12 shown in FIG. 1 causes the memory unit 13 to memorize, for example, 0.5 and -0.5 as upper and lower limits. The determination unit 14 uses the value of the storage unit 13 as a threshold, and determines the magnitude relationship between it and the measured current value. Then, if the measured current value is above -0.5 and less than 0.5, it is regarded as normal. That is, it is determined that the current path is not broken. If the measured current value is 0.5 or more, the first current path CA11 is regarded as broken. In addition, if the measured current value does not reach -0.5, it is regarded as a disconnection of the second current path CA12. That is, this is detected as a sign that the cable 31 is broken.

Secondly, it shows an example of a broken sign when detecting a situation where a cable is composed of three current paths.

7 is a circuit diagram of a heating device that differs from the heating device shown in FIG. 1 in the configuration of the cable 31. In this example, the cable 31 is composed of three current paths CA11, CA12, and CA13. The current detection unit 4 detects the current flowing through the current path CA13.

FIG. 8 shows the current flowing through the first current path CA11, the current flowing through the second current path CA12, the current flowing through the third current path CA13, and the measurement results of the current detection unit 4 in the disconnected state of the specific part Diagram of the relationship. In FIG. 8, i11 is the current flowing through the first current path CA11, i12 is the current flowing through the second current path CA12, i13 is the current flowing through the third current path CA13, and iCT is the detection value of the current detection unit 4 . In either case, the current flowing through the heater 2 is set to a relative value at 1.0.

When there is no disconnection in any current path, the current flowing through the first current path CA11, the second current path CA12, and the third current path CA13 is 1/3, and the measured current value is 1/3. When the first current path CA11 is disconnected, the current flowing through the heater 2 flows through the second current path CA12 and the third current path CA13, so the current flowing through the third current path CA13 becomes 0.5 and the measured current value becomes 0.5. When the second current path CA12 is disconnected, the current flowing through the heater 2 flows through the first current path CA11 and the third current path CA13, so the current flowing through the third current path CA13 becomes 0.5 and the measured current value becomes 0.5. When the third current path CA13 is disconnected, the current flowing through the third current path CA13 becomes 0, and the measured current value becomes 0. When the heater itself is disconnected, the measured current value becomes zero.

In the example shown in FIG. 7, the setting section 12 shown in FIG. 1 causes the memory section 13 to pre-store the intermediate value of 1/3 and 0, that is, 0.166 as the lower limit value, and pre-store the intermediate value of 0.5 and 1/3, that is 0.416 as the upper limit. The determination unit 14 uses the value of the storage unit 13 as a threshold, and determines the magnitude relationship between it and the measured current value. Then, if the measured current value is above 0.166 and less than 0.416, it is regarded as normal. That is, it is determined that the current path is not broken. If the measured current value is 0.416 or more, it is regarded that the first current path CA11 or the second current path CA12 is disconnected. If the measured current value does not reach 0.166, the third current path CA13 is regarded as broken. That is, this is detected as a sign that the cable 31 is broken.

Furthermore, when the heater 2 is disconnected, the measured current value also becomes 0. Therefore, in this embodiment, the disconnection of the third current path CA13 and the heater 2 cannot be distinguished.

FIG. 9 is a circuit diagram of a heating device that differs from the example shown in FIG. 7 in the configuration of the current detection unit. In this example, the cable 31 is composed of three current paths CA11, CA12, and CA13. The current detection unit 4 detects the added value of the current flowing through the current path CA12 and the current flowing through the current path CA13.

FIG. 10 shows the current flowing through the first current path CA11, the current flowing through the second current path CA12, the current flowing through the third current path CA13, and the measurement results of the current detection unit 4 in the disconnected state of the specific part Diagram of the relationship. In FIG. 10, i11 is the current flowing through the first current path CA11, i12 is the current flowing through the second current path CA12, i13 is the current flowing through the third current path CA13, and iCT is the detection value of the current detection unit 4 . In either case, the current flowing through the heater 2 is set to a relative value at 1.0.

When there is no disconnection in any current path, the current flowing through the first current path CA11, the second current path CA12, and the third current path CA13 is 1/3, and the measured current value is 2/3. When the first current path CA11 is disconnected, the current flowing through the heater 2 flows through the second current path CA12 and the third current path CA13, so the measured current value becomes 1.0. When the second current path CA12 is disconnected, the current flowing through the heater 2 flows through the first current path CA11 and the third current path CA13, so the measured current value becomes 0.5. When the third current path CA13 is disconnected, the current flowing through the heater 2 flows through the first current path CA11 and the second current path CA12, so the measured current value becomes 0.5. When the heater itself is disconnected, the measured current value becomes zero.

In the example shown in FIG. 9, the setting section 12 shown in FIG. 1 causes the memory section 13 to pre-store the intermediate value of 2/3 and 0.5, or 0.583, as the lower limit value, and pre-store the intermediate value of 1.0 and 2/3, namely 0.833 as the upper limit. The determination unit 14 uses the value of the storage unit 13 as a threshold, and determines the magnitude relationship between it and the measured current value. Then, if the measured current value is above 0.583 and less than 0.833, it is regarded as normal. That is, it is determined that the current path is not broken. If the measured current value is 0.833 or more, the first current path CA11 is regarded as broken. In addition, if the measured current value does not reach 0.583, it is regarded that the second current path CA12 or the third current path CA13 is broken. That is, this is detected as a sign that the cable 31 is broken.

11 is a circuit diagram of a heating device in which the current detection unit 4 detects the current flowing through the three current paths CA11, CA12, and CA13 constituting the cable 31. In this example, the cable 31 is composed of three current paths CA11, CA12, and CA13. The current detection unit 4 detects a value obtained by subtracting the current flowing through the current path CA11 from the added value of the current flowing through the current path CA12 and the current flowing through the current path CA13.

12 is a graph showing the current flowing through the first current path CA11, the current flowing through the second current path CA12, the current flowing through the third current path CA13, and the measurement results of the current detection unit 4 in the disconnected state of the specific part Diagram of relationship. In FIG. 12, i11 is the current flowing through the first current path CA11, i12 is the current flowing through the second current path CA12, i13 is the current flowing through the third current path CA13, and iCT is the detection value of the current detection unit 4 . In either case, the current flowing through the heater 2 is set to a relative value at 1.0.

When there is no disconnection in any current path, the current flowing through the first current path CA11, the second current path CA12, and the third current path CA13 is 1/3, and the measured current value is 1/3. When the first current path CA11 is disconnected, the current flowing through the heater 2 flows through the second current path CA12 and the third current path CA13, so the measured current value becomes 1.0. When the second current path CA12 is disconnected, the current flowing through the heater 2 flows through the first current path CA11 and the third current path CA13, so the measured current value becomes zero. When the third current path CA13 is disconnected, the current flowing through the heater 2 flows through the first current path CA11 and the second current path CA12, so the measured current value becomes zero. When the heater itself is disconnected, the measured current value becomes zero.

In the example shown in FIG. 11, the setting unit 12 shown in FIG. 1 causes the memory unit 13 to pre-store the intermediate value of 1/3 and 0, that is, 0.166 as the lower limit value, and pre-store the intermediate value of 1.0 and 1/3, that is 0.666 is taken as the upper limit. The determination unit 14 uses the value of the storage unit 13 as a threshold, and determines the magnitude relationship between it and the measured current value. Then, if the measured current value is above 0.166 and less than 0.666, it is regarded as normal. That is, it is determined that the current path is not broken. If the measured current value is 0.666 or more, the first current path CA11 is regarded as broken. In addition, if the measured current value does not reach 0.166, it is regarded that the second current path CA12 or the third current path CA13 is broken. That is, this is detected as a sign that the cable 31 is broken.

Fig. 13 is a circuit diagram of a heating device different from the example shown in Fig. 1. In this example, the current detection unit 4 detects the difference between the current flowing through the current path CA12 of the two current paths CA11 and CA12 constituting the first cable 31 and the current flowing through the current path CA2 constituting the second cable .

FIG. 14 is a diagram showing the relationship between the current flowing through the current paths CA11, CA12, and CA2 and the measurement result of the current detection unit 4 in a disconnected state at a specific location. In FIG. 14, i11 is the current flowing through the current path CA11, i12 is the current flowing through the current path CA12, i2 is the current flowing through the current path CA2, and iCT is the detection value of the current detection unit 4. In either case, the current flowing through the heater 2 is set to a relative value at 1.0.

When there is no disconnection in any current path, the current flowing through the current paths CA11 and CA12 is 0.5, and the current flowing through the current path CA2 is 1.0, so the measured current value is -0.5. When the current path CA11 is disconnected, the current flowing through the heater 2 flows through the current path CA12 and the current path CA2, so the measured current value becomes zero. When the current path CA12 is disconnected, the current flowing through the heater 2 flows through the current path CA11 and the current path CA2, so the measured current value becomes -1.0. When the current path CA2 is disconnected, the measured current value becomes 0. When the heater itself is disconnected, the measured current value also becomes zero.

In the example shown in FIG. 13, the setting unit 12 shown in FIG. 1 causes the memory unit 13 to memorize the intermediate value of -0.5 and 0, that is, -0.25 as the upper limit value in advance. In addition, the intermediate value of -0.5 and -1.0, that is, -0.75, is memorized in advance as the lower limit value. The determination unit 14 uses the value of the storage unit 13 as a threshold, and determines the magnitude relationship between it and the measured current value. Then, if the measured current value is above -0.75 and less than -0.25, it is regarded as normal. That is, it is determined that the current path is not broken. If the measured current value is -0.25 or more, it is considered that either of the current paths CA11 and CA2 is broken. In addition, if the measured current value does not reach -0.75, it is regarded as a disconnection of the current path CA12. These are detected as a sign that the cable 31 is broken.

Fig. 15 is a circuit diagram of a heating device different from the example shown in Fig. 1. In this example, the current detection unit 4 detects the sum of the current flowing through the current path CA12 of the two current paths CA11 and CA12 constituting the first cable 31 and the current flowing through the current path CA2 constituting the second cable .

FIG. 16 is a diagram showing the relationship between the current flowing through the current paths CA11, CA12, and CA2 and the measurement result of the current detection unit 4 in a disconnected state at a specific location. In FIG. 16, i11 is the current flowing through the current path CA11, i12 is the current flowing through the current path CA12, i2 is the current flowing through the current path CA2, and iCT is the detection value of the current detection unit 4. In either case, the current flowing through the heater 2 is set to a relative value at 1.0.

When there is no disconnection in any current path, the current flowing through the current paths CA11 and CA12 is 0.5, and the current flowing through the current path CA2 is 1.0, so the measured current value is 1.5. When the current path CA11 is disconnected, the current flowing through the heater 2 flows through the current path CA12 and the current path CA2, so the measured current value becomes 2.0. When the current path CA12 is disconnected, the current flowing through the heater 2 flows through the current path CA11 and the current path CA2, so the measured current value becomes 1.0. When the current path CA2 is disconnected, the measured current value becomes 0. When the heater itself is disconnected, the measured current value also becomes zero.

In the example shown in FIG. 15, the setting section 12 shown in FIG. 1 causes the memory section 13 to pre-store the intermediate value of 1.5 and 1, which is 1.25, as the lower limit value, and pre-store the intermediate value of 2.0 and 1.5, or 1.75, as the upper limit. value. The determination unit 14 uses the value of the storage unit 13 as a threshold, and determines the magnitude relationship between it and the measured current value. Then, if the measured current value is above 1.25 and does not reach 1.75, it is regarded as normal. That is, it is determined that the current path is not broken. If the measured current value is 1.75 or more, the current path CA11 is regarded as broken. In addition, if the measured current value does not reach 1.25, it is regarded as that the current path CA12 or the current path CA2 is broken. That is, this is detected as a sign that the cable 31 is broken.

Fig. 17 is a circuit diagram of a heating device different from the example shown in Fig. 1. In this example, the current detection unit 4 detects the current flowing through the current path CA12 of the two current paths CA11 and CA12 that constitute the first cable 31 and the two current paths CA21 that form the second cable 32, The sum of the currents in CA22 in CA22.

FIG. 18 is a diagram showing the relationship between the current flowing through the current paths CA11, CA12, CA21, and CA22 and the measurement result of the current detection unit 4 in a disconnected state at a specific location. In FIG. 18, i11 is the current flowing through the current path CA11, i12 is the current flowing through the current path CA12, i21 is the current flowing through the current path CA21, i22 is the current flowing through the current path CA22, and iCT is the current detection unit 4 Of the detection value. In either case, the current flowing through the heater 2 is set to a relative value at 1.0.

When there is no disconnection in any current path, the current flowing through the current paths CA11, CA12, CA21, CA22 is 0.5, so the measured current value is 1.0. When the current path CA11 is disconnected, the current flowing through the heater 2 flows through the current path CA12, so the measured current value becomes 1.5. When the current path CA12 is disconnected, the current flowing through the heater 2 flows through the current path CA11, so the measured current value becomes 0.5. When the current path CA21 is disconnected, the current flowing through the heater 2 flows through the current path CA22, so the measured current value becomes 1.5. When the current path CA22 is disconnected, the measured current value becomes 0.5. When the heater itself is disconnected, the measured current value becomes zero.

In the example shown in FIG. 17, the setting unit 12 shown in FIG. 1 causes the memory unit 13 to memorize the intermediate value of 1.0 and 0.5, namely 0.75, as the lower limit value, and memorize the intermediate value of 1.0 and 1.5, or 1.25, as the upper limit. value. The determination unit 14 uses the value of the storage unit 13 as a threshold, and determines the magnitude relationship between it and the measured current value. Then, if the measured current value is above 0.75 and less than 1.25, it is regarded as normal. That is, it is determined that the current path is not broken. If the measured current value does not reach 0.75, it is considered that any of the current paths CA12 and CA22 is broken. In addition, if the measured current value is 1.25 or more, any one of the current paths CA11 and CA21 is regarded as broken. That is, this is detected as a sign that the cable 31 is broken.

Fig. 19 is a circuit diagram of a heating device different from the example shown in Fig. 1. In this example, the current detection unit 4 detects the current flowing through the current path CA12 of the two current paths CA11 and CA12 that constitute the first cable 31 and the two current paths CA21 that form the second cable 32, The current difference in the current path CA22 in CA22.

FIG. 20 is a diagram showing the relationship between the current flowing through the current paths CA11, CA12, CA21, CA22 and the measurement result of the current detection unit 4 in the disconnected state of a specific part. In FIG. 20, i11 is the current flowing through the current path CA11, i12 is the current flowing through the current path CA12, i21 is the current flowing through the current path CA21, i22 is the current flowing through the current path CA22, and iCT is the current detection unit The detection value of 4. In either case, the current flowing through the heater 2 is set to a relative value at 1.0.

When there is no disconnection in any current path, the current flowing through the current paths CA11, CA12, CA21, CA22 is 0.5, so the measured current value is 0. When the current path CA11 is disconnected, the current flowing through the heater 2 flows through the current path CA12, so the measured current value becomes 0.5. When the current path CA12 is disconnected, the current flowing through the heater 2 flows through the current path CA11, so the measured current value becomes -0.5. When the current path CA21 is disconnected, the current flowing through the heater 2 flows through the current path CA22, so the measured current value becomes -0.5. When the current path CA22 is disconnected, the measured current value becomes 0.5. When the heater itself is disconnected, the measured current value becomes zero.

In the example shown in FIG. 19, the setting section 12 shown in FIG. 1 causes the memory section 13 to pre-store the intermediate value of 0 and -0.5, that is, -0.25 as the lower limit value, and pre-store the intermediate value of 0 and 0.5, which is 0.25 as Upper limit. The determination unit 14 uses the value of the storage unit 13 as a threshold, and determines the magnitude relationship between it and the measured current value. Then, if the measured current value is above -0.25 and less than 0.25, it is regarded as normal. That is, it is determined that the current path is not broken. If the measured current value does not reach -0.25, it is considered that either of the current paths CA12 and CA21 is broken. In addition, if the measured current value is 0.25 or more, any one of the current paths CA11 and CA22 is regarded as broken. That is, this is detected as a sign that the cable 31 is broken.

Fig. 21 is a circuit diagram of a heating device different from the example shown in Fig. 1. In this example, the current detection unit 4 detects the difference between the currents flowing through the two current paths CA11 and CA12 constituting the first cable 31 and the two current paths CA21 and CA22 constituting the second cable 32 The difference in current in the current path CA22.

FIG. 22 is a diagram showing the relationship between the current flowing through the current paths CA11, CA12, CA21, and CA22 in a disconnected state at a specific location, and the measurement result of the current detection unit 4. In FIG. 22, i11 is the current flowing through the current path CA11, i12 is the current flowing through the current path CA12, i21 is the current flowing through the current path CA21, i22 is the current flowing through the current path CA22, and iCT is the current detection unit The detection value of 4. In either case, the current flowing through the heater 2 is set to a relative value at 1.0.

When there is no disconnection in any current path, the current flowing through the current paths CA11, CA12, CA21, CA22 is 0.5, so the measured current value is 0.5. When the current path CA11 is disconnected, the current flowing through the heater 2 flows through the current path CA12, so the measured current value becomes 1.5. When the current path CA12 is disconnected, the current flowing through the heater 2 flows through the current path CA11, so the measured current value becomes -0.5. When the current path CA21 is disconnected, the current flowing through the heater 2 flows through the current path CA22, so the measured current value becomes 1.0. When the current path CA22 is disconnected, the measured current value becomes 0. When the heater itself is disconnected, the measured current value becomes zero.

In the example shown in FIG. 21, the setting unit 12 shown in FIG. 1 causes the memory unit 13 to memorize the intermediate value of 0 and 0.5, namely 0.25, as the lower limit value, and memorize the intermediate value of 0.5 and 1.0, or 0.75, as the upper limit. value. The determination unit 14 uses the value of the storage unit 13 as a threshold, and determines the magnitude relationship between it and the measured current value. Then, if the measured current value is more than 0.25 and less than 0.75, it is regarded as normal. That is, it is determined that the current path is not broken. If the measured current value does not reach 0.25, it is considered that any of the current paths CA12 and CA22 is broken. In addition, if the measured current value is 0.75 or more, any one of the current paths CA11 and CA21 is regarded as broken. That is, this is detected as a sign that the cable 31 is broken.

Fig. 23 is a circuit diagram of a heating device different from the example shown in Fig. 1. In this example, not only the first cable 31 side shown in FIG. 1 but also the second cable 32 side is also provided with a current detection section, which detects a broken cable based on the detection results of the two current detection sections omen. In this heating device, whether the current paths CA21 and CA22 of the second cable 32 are disconnected can be detected by the same principle as the example shown in FIG. 1, whereby the disconnection of the second cable 32 can also be detected Omens.

In the same manner, the structure of the current detection unit shown in FIGS. 5, 7, 9, 9, 11, 13, 15, 17, 19, 21, etc. can be provided on the side of the second cable 32 , Based on the detection results of the two current detection parts, to detect the broken sign of the cable.

The example shown above shows a device that connects two cables to a load with two terminals, but the same applies to devices that connect cables to a load with more than three terminals. For example, FIG. 24 is an example in which a three-phase AC power supply is connected to a heater 2 as a three-phase AC load via a cable. In this example, the heater 2 is connected to each line of the three-phase AC power supply through two current paths. Furthermore, one of the two current paths of each phase is connected to the current detection units CT1, CT2, and CT3, respectively.

FIG. 25 is a diagram showing the relationship between the currents flowing through the current paths CA11, CA12, CA21, CA22, CA31, CA32 and the detection results of the current detection units CT1, CT2, and CT3 in the disconnected state of a specific part. In FIG. 24, i11 is the current flowing through the current path CA11, i12 is the current flowing through the current path CA12, i21 is the current flowing through the current path CA21, i22 is the current flowing through the current path CA22, and i31 is the current flowing through the current path The current of CA31, i32 is the current flowing through the current path CA32, iCT1 is the detection value of the current detection section CT1, iCT2 is the detection value of the current detection section CT2, and iCT3 is the detection value of the current detection section CT3. In either case, the relative value when the phase current flowing through the heater 2 is set to 1.0.

As in the example shown in FIGS. 1 and 2, the threshold value of the lower limit compared with the detection value of the current detection unit CT1 is defined as 0.25, and the threshold value of the upper limit is defined as 0.75. The same applies to the current detection units CT2 and CT3. In this way, according to the detection results of the three current detection sections CT1, CT2, and CT3, the disconnection signs of the cables 31, 32, and 33 can be detected.

Finally, the above description of the form for carrying out the invention does not need to be restated, and it is an example in all respects, not a limitation. The operator can appropriately transform and change.

For example, when a cable riveting portion is provided at a portion where the cable is branched into multiple current paths, but when the contact resistance of the cable riveting portion is not equal, the split ratio for the multiple current paths does not become equal ratio. In this case, it is sufficient to specify the threshold according to the actual shunting ratio to the multiple current paths.

In addition, FIG. 4 shows an example in which the threshold value is determined based on the measured initial current value, but there are cases where the normal current value changes due to the year-to-year change of the load, cable, cable connection, etc., Therefore, it may be configured to reset the threshold according to the measured current value at a specific timing.

Furthermore, in the above-described embodiment, a heating device using a heater as a load is exemplified, but it can be similarly applied to a device using a motor or an electromagnet as a load.

In addition, in each of the above-described embodiments, a current transformer (current transformer) is used as the current detection unit. However, in addition, for example, a resistance element for current detection may be inserted into each current path and reduced according to the Voltage to detect the current flowing through the current path. In this case, it is sufficient to provide a rectifier circuit for determining the peak value of the current, a polarity determination section for determining the polarity of the sine wave, and an arithmetic section for performing addition and subtraction operations in consideration of the polarities of the peak values determined for multiple current paths.

CA11‧‧‧First current path CA12‧‧‧ 2nd current path CA13‧‧‧3rd current path CA2‧‧‧current path CA21, CA22 ‧‧‧ current path CA31, CA32‧‧‧ Current path CT1, CT2, CT3 ‧‧‧ Current Detection Department 1‧‧‧Power 2‧‧‧heater 4‧‧‧Current Detection Department 5‧‧‧Opening and Closing Department 10‧‧‧Alarm Department 11‧‧‧Current Measurement Department 12‧‧‧Setting Department 13‧‧‧ Memory Department 14‧‧‧Judgment Department 15‧‧‧ Abnormal output section 16‧‧‧Output 20‧‧‧Control Department 31‧‧‧ First cable 32‧‧‧ 2nd cable 33‧‧‧Cable 101‧‧‧Heating device 201‧‧‧Cable disconnection warning device

FIG. 1 is a diagram showing the overall configuration of a heating device including a cable breakage detection device according to an embodiment of the present invention. FIG. 2 is a diagram showing the relationship between the current flowing through the first current path CA11, the current flowing through the second current path CA12, and the measurement result of the current detection unit 4 in a disconnected state at a specific location. Fig. 3 is a graph showing the relationship between the threshold value and the measured current value. FIG. 4 is a flowchart showing the processing contents of the control unit 20 shown in FIG. 1. FIG. 5 is a circuit diagram of a heating device that differs from the heating device shown in FIG. 1 in the configuration of the current path detected by the current detection unit 4. 6 is a diagram showing the relationship between the current flowing through the first current path CA11, the current flowing through the second current path CA12, and the measurement result of the current detection unit 4 in a disconnected state at a specific location. 7 is a circuit diagram of a heating device that differs from the heating device shown in FIG. 1 in the configuration of the cable 31. FIG. 8 shows the current flowing through the first current path CA11, the current flowing through the second current path CA12, the current flowing through the third current path CA13, and the measurement results of the current detection unit 4 in the disconnected state of the specific part Diagram of the relationship. FIG. 9 is a circuit diagram of a heating device that differs from the example shown in FIG. 7 in the configuration of the current detection unit. FIG. 10 shows the current flowing through the first current path CA11, the current flowing through the second current path CA12, the current flowing through the third current path CA13, and the measurement results of the current detection unit 4 in the disconnected state of the specific part Diagram of the relationship. FIG. 11 is a circuit diagram of a heating device in which the current detection unit 4 detects the current flowing through the three current paths CA11, CA12, and CA13 constituting the cable 31. FIG. 12 shows the current flowing through the first current path CA11, the current flowing through the second current path CA12, the current flowing through the third current path CA13, and the measurement results of the current detection unit 4 in the disconnected state of the specific part Diagram of the relationship. Fig. 13 is a circuit diagram of a heating device different from the example shown in Fig. 1. FIG. 14 is a diagram showing the relationship between the current flowing through the current paths CA11, CA12, and CA2 and the measurement result of the current detection unit 4 in a disconnected state at a specific location. Fig. 15 is a circuit diagram of a heating device different from the example shown in Fig. 1. FIG. 16 is a diagram showing the relationship between the current flowing through the current paths CA11, CA12, and CA2 and the measurement result of the current detection unit 4 in a disconnected state at a specific location. Fig. 17 is a circuit diagram of a heating device different from the example shown in Fig. 1. FIG. 18 is a diagram showing the relationship between the current flowing through the current paths CA11, CA12, CA21, and CA22 and the measurement result of the current detection unit 4 in a disconnected state at a specific location. Fig. 19 is a circuit diagram of a heating device different from the example shown in Fig. 1. FIG. 20 is a diagram showing the relationship between the current flowing through the current paths CA11, CA12, CA21, CA22 and the measurement result of the current detection unit 4 in the disconnected state of a specific part. Fig. 21 is a circuit diagram of a heating device different from the example shown in Fig. 1. FIG. 22 is a diagram showing the relationship between the current flowing through the current paths CA11, CA12, CA21, and CA22 in a disconnected state at a specific location, and the measurement result of the current detection unit 4. Fig. 23 is a circuit diagram of a heating device different from the example shown in Fig. 1. Fig. 24 is an example of a device in which a three-phase AC power supply is connected to a heater 2 as a three-phase AC load via a cable. FIG. 25 is a diagram showing the relationship between the currents flowing through the current paths CA11, CA12, CA21, CA22, CA31, CA32 and the detection results of the current detection units CT1, CT2, and CT3 in the disconnected state of a specific part.

CA11‧‧‧First current path

CA12‧‧‧ 2nd current path

1‧‧‧Power

2‧‧‧heater

4‧‧‧Current Detection Department

5‧‧‧Opening and Closing Department

10‧‧‧Alarm Department

11‧‧‧Current Measurement Department

12‧‧‧Setting Department

13‧‧‧ Memory Department

14‧‧‧Judgment Department

15‧‧‧ Abnormal output section

16‧‧‧Output

20‧‧‧Control Department

31‧‧‧ First cable

32‧‧‧ 2nd cable

101‧‧‧Heating device

201‧‧‧Cable disconnection warning device

Claims (3)

A cable breakage precursor detection device, which is a device for detecting breakage precursors of a plurality of cables respectively connected to a plurality of connection parts of a load and passing current to the load, the cable includes a connection to the load The first cable of the first connection part of the plurality of connection parts, and the second cable of the second connection part of the plurality of connection parts connected to the load, the first cable is composed of a plurality of parallel connections The first current path is constituted, and the second cable is composed of a plurality of second current paths connected in parallel, and the cable breakage precursor detection device includes: a current detection section that detects the flow of the plurality of first currents The sum or difference between the current of at least one current path in the path and the current flowing through at least one current path of the plurality of second current paths; and an alarm section that compares the detection value of the current detection section with a threshold To detect the power-on state of the first current paths and the power-on state of the second current paths, to determine whether the first current paths and the second current paths are disconnected. When disconnected, an alarm will sound. A cable breakage precursor detection device, which is a device for detecting breakage precursors of a plurality of cables respectively connected to a plurality of connection parts of a load and passing current to the load, the cable includes a connection to the load The first cable of the first connection part of the plurality of connection parts, and the second cable of the second connection part of the plurality of connection parts connected to the load, the first cable is composed of a plurality of parallel connections The first current path is constituted, and the second cable is composed of a plurality of second current paths connected in parallel, and the cable breakage precursor detection device includes: a current detection unit that detects the flow of the second currents The sum or difference of the currents of at least one current path in the path to the currents flowing through at least two current paths in the first current paths Or difference; and an alarm part, which compares the detection value of the current detection part with a threshold value, detects the energization state of the plurality of first current paths and the energization state of the plurality of second current paths, thereby determining the plurality of Whether the first current path and the plurality of second current paths are disconnected, an alarm is issued when it is determined that there is a disconnection. The cable breakage precursor detection device according to claim 1 or 2, wherein the threshold value is specified based on the detection value of the current detection unit in an initial state.

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