JP4590983B2 - Load capacity detector for wiring duct - Google Patents

Description

  The present invention relates to a load capacity detector for a wiring duct in which a conductor is installed, and more specifically, detects a load capacity of a conductor disposed inside a wiring duct having an opening formed on one side surface. The present invention relates to a load capacity detector for a wiring duct.

  Conventionally, for example, as a wiring duct for supplying power to a plurality of loads such as various power machines and lighting fixtures installed in a factory, a network server, a router, etc., a pair of conductors are arranged in parallel in a steel plate case. What is provided as such is known. Such a wiring duct has a case that is large in the longitudinal direction and a pair of conductors that are large in the longitudinal direction, and is connected to an external power source via a switchboard so that it can be easily connected to a large number of loads. It is laid on the ceiling. Then, power is branched and supplied to a load that is attached to an appropriate place in the longitudinal direction of the wiring duct and that is electrically connected to the conductor in the case.

  In addition, the wiring duct has a capacity that can be supplied to the load, and the load is connected within the range of the load capacity. Therefore, when connecting this wiring duct and a load, it is necessary to consider the load capacity, and it is necessary to detect the load capacity flowing through the wiring duct.

  As a technique for detecting the load capacity of the wiring duct in this way, as shown in FIG. 7, the power line 102 connecting the wiring duct and the AC power source 101 is sandwiched between the clamp arms 103a of the clamp meter 103, and the wiring duct is connected. The supplied current value was detected. Further, as shown in FIG. 8, an ammeter 104 is provided in series with the power supply line 102 to detect a current value. Furthermore, as shown in FIG. 9, there is a technique in which a power line connected to a breaker 106 inside the distribution board 105 is sandwiched between clamp arms 103a. Furthermore, as shown in FIG. 10, there is also a technique for connecting an outlet bar 107 having a plurality of outlet portions for connecting a wiring duct and a load, and a current measuring device 108 for displaying a current value.

Furthermore, as a method for measuring the load capacity of the wiring duct, for example, those described in Patent Document 1 and Patent Document 2 below are known. In this technique, a voltage detection means such as a coil fixed between conductors of a wiring duct is provided, and an induced voltage generated between conductors is detected by arranging the voltage detection means in the wiring duct during current measurement. It was a thing.
JP 2003-315387 A Japanese Patent Laying-Open No. 2004-153920 (paragraph numbers 0062 to 0067, FIG. 5)

  However, in the technique described with reference to FIGS. 7 and 8 described above, it is necessary to provide the clamp meter 103 and the ammeter 104 by opening a feed-in portion that is a connection mechanism between the wiring duct and the power supply line 102. In addition to the technique described with reference to FIG. 7, the technique described with reference to FIG. 9 may cause the clamp meter 103 to touch the power supply line 102, which may cause a breaker trip due to a short circuit. It was. Furthermore, in the technique described with reference to FIG. 10, it is necessary to temporarily disconnect the power supply from the power source to the wiring duct and connect the current measuring instrument 108 and the outlet bar 107.

  Furthermore, in the technique described in the above-mentioned Patent Document 1 and the technique including a circuit that converts to a digital signal as in Patent Document 2, when noise superimposed on the power supplied to the wiring duct occurs, When the measured value of the load capacity detector connected to the wiring duct is managed by a PC or the like, there is a problem that if the distance between the load capacity detector and the PC becomes long, the accurate load capacity cannot be measured. .

  Therefore, the present invention has been proposed in view of the above-described situation, and provides a load capacity detector for a wiring duct that can easily and accurately detect the load capacity of a wiring duct with a conductor built therein. The purpose is to do.

The present invention relates to a load capacity detector for detecting a load capacity of a wiring duct in which a positive and negative parallel conductor is disposed inside a case having an opening formed on one side surface, and the inside of the case from the opening. And two coils that are inserted in the middle of each other and are arranged in the approximate center between the parallel conductors, and each generate an induced voltage with an opposite phase due to the magnetic flux generated as a current flows through the parallel conductors. The voltage detection means is connected to a constant power source that applies a constant voltage to the connection portion of the two coils, and the voltage detection means is detachably connected to the peripheral edge of the opening of the case. A detecting means having a locking means for stopping, and an output means for outputting the load capacity of the wiring duct determined according to the voltage detected by the voltage detecting means to a display means for displaying the load capacity, The detection means is The voltage detecting means comprises an amplifying means for differentially amplifying each voltage induced in each coil, and an A / D converting means for discretizing the amplified voltage, and the output means is the discretized A voltage value is output to the display means.

  According to the load capacity detector for a wiring duct according to the present invention, the induced magnetic flux generated in response to the current flowing through the parallel conductor is received by two coils connected in series, so that the induced voltages of opposite phases are generated in the respective coils. Thus, the noise of the detected value of the coil can be canceled by the induced voltage having the opposite phase, and the load capacity of the wiring duct in which the conductor is built can be detected easily and accurately.

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

  FIG. 1 is a perspective view showing a state in which a load capacity detector 3 to which the present invention is applied is attached to the wiring duct 1, and FIG. 2 is a wiring diagram when the load capacity detector 3 is attached to the wiring duct 1. 3 is a cross-sectional view of the duct 1, FIG. 3 is a perspective view when the load capacity detector 3 is attached to the wiring duct 1, FIG. 4 is an exploded configuration diagram of the load capacity detector 3, and FIG. FIG. 6 is a cross-sectional view of an air-core coil that is a voltage detection means, and FIG. 6 is a functional block diagram for displaying a detection value of the load capacitance detector 3.

  As shown in FIG. 1, the present invention detects the load capacity of a wiring duct 1 that extends in the longitudinal direction and to which a plurality of outlet portions 2 are attached. In the wiring duct 1, a power load or the like is connected to each outlet portion 2 via a power line. The wiring duct 1 is connected to a distribution board (not shown) or the like via the feed-in unit 11 to be supplied with power. Thereby, the wiring duct 1 supplies electric power to a plurality of power loads via the outlet portion 2. In addition, a load capacity detector 3 is attached to the wiring duct 1 in the same manner as the outlet portion 2.

  As shown in FIG. 2, the wiring duct 1 is attached to a steel plate case 20 in which an opening is formed along one side surface (upper side surface in the figure), and the mounting portion 21 from the case 20. A pair of parallel conductors 22 is provided. These parallel conductors 22 are disposed along the longitudinal direction in the same manner as the case 20, and are electrically connected to the outlet portion 2 to be a positive electrode or a negative electrode. In addition, this wiring duct 1 is coat | covered with the resin coating which has insulation from the most surroundings except the parallel conductor 22. FIG.

  As shown in FIG. 2, the load capacity detector 3 has a sensor case 31 and a case 20 in contact with such a wiring duct 1 and a wiring duct fixing portion 32 inserted into the sensor case 31. The case 20 is engaged with the peripheral edge of the opening. As shown in FIG. 3A, the wiring duct fixing portion 32 made of an insulator is inserted into the opening 1 a of the wiring duct 1 and rotated to be locked to the case 20. Thus, in the state where the load capacity detector 3 is locked to the case 20, the air-core coil 33, which is a voltage detection means, is in a state of being inserted approximately at the center of the pair of parallel conductors 22.

  That is, the air-core coil 33 is configured to always face the parallel conductor 22 in the case 20 with a certain distance therebetween. Specifically, the current flows through the parallel conductor 22 included in the wiring duct 1. A voltage is induced by the magnetic flux generated as it flows. At this time, the voltage value of the induced voltage detected by the air-core coil 33 is linearly proportional to the current value of the current flowing through the parallel conductor 22.

  As shown in FIG. 5, the air-core coil 33 is configured by winding two first coils 33 </ b> A and second coils 33 </ b> B around a coil bobbin 41 attached to the coil housing portion 34. . Therefore, the first coil 33 </ b> A and the second coil 33 </ b> B each induce a voltage when a magnetic flux corresponding to the current flowing through the parallel conductor 22 is applied.

  As shown in FIG. 6, the air-core coil 33 is connected to a constant power source 51 that applies a constant voltage (for example, about 2.5 [V]) to a connection portion between the first coil 33 </ b> A and the second coil 33 </ b> B. Thus, a current flows through the first coil 33A and the second coil 33B. Therefore, the induced voltage of the first coil 33A and the induced voltage of the second coil 33B are in opposite phases.

  As shown in FIG. 4, the load capacity detector 3 includes a coil housing portion 34 that houses the air-core coil 33 and a sensor substrate 35 that is electrically connected to the air-core coil 33. Then, the sensor housing 31 is inserted. The sensor casing 31 is provided with a cable fixing portion 37 for fixing a sensor cable 36 connected to a personal computer described later.

  The sensor substrate 35 and the sensor cable 36 are electrically connected, and the calculation result of the load capacity by the sensor substrate 35 can be transmitted via the sensor cable 36. In the load capacity detector 3, the sensor casing 31 and the wiring duct fixing portion 32 are connected and fixed in a state where the sensor substrate 35 is inserted into the sensor casing 31.

  The sensor substrate 35 includes a control circuit 38 connected to the air-core coil 33 via a lead wire. The control circuit 38 is connected to the lead wire 39 in the sensor substrate 35, and is connected to the sensor cable 36 from the lead wire 39. The control circuit 38 supplies a constant voltage to one end of the first coil 33A and the second coil 33B, and is connected to the other end of the first coil 33A and the second coil 33B.

  As shown in FIG. 6, the control circuit 38 includes an amplification unit 52, an A / D conversion unit 53, and a calculation unit 54 connected to the first coil 33 </ b> A and the second coil 33 </ b> B. It is connected to a personal computer equipped with In such a control circuit 38, the load capacity detector 3 is attached to the wiring duct 1, and an induced voltage having an opposite phase is supplied from the first coil 33 </ b> A and the second coil 33 </ b> B to the amplifying unit 52.

  At this time, the amplifying unit 52 amplifies a differential voltage between the induced voltage of the first coil 33A and the induced voltage of the second coil 33B. Here, each of the induced voltage of the first coil 33A and the induced voltage of the second coil 33B includes a noise component superimposed on the current flowing in the wiring duct 1, the first coil 33A and the second coil 33B itself, The noise component applied to the electric circuit which connects the coil 33A and the 2nd coil 33B, and the control circuit 38 is contained. On the other hand, the amplifying unit 52 obtains a voltage that cancels out the noise component by taking the difference between the induced voltage of the first coil 33A and the induced voltage of the second coil 33B.

  The A / D conversion unit 53 converts the voltage amplified by the amplification unit 52 into a digitized digital value, and the calculation unit 54 converts the digital value from the A / D conversion unit 53 into the load capacity of the wiring duct 1. Calculate a certain effective value. Here, the calculation unit 54 is supplied with an effective value calculation formula from a personal computer including the display unit 60. When the digital value is supplied from the A / D conversion unit 53, the calculation unit 54 uses the calculation formula given from the personal computer, that is, the effective value of the load capacity, that is, the current value flowing through the parallel conductor 22. Is calculated and transmitted to the personal computer via the sensor cable 36.

  When the display unit 60 receives the effective value of the load capacity from the load capacity detector 3, the display unit 60 displays the effective value of the load capacity and presents it to the administrator of the wiring duct 1 or the like.

  Thus, the magnetic flux generated by the current flowing through the parallel conductor 22 is received by both the first coil 33A and the second coil 33B, and the first coil 33A and the second coil 33B are connected in series, and the amplifying unit 52, the difference between the induced voltages of the first coil 33A and the second coil 33B can be obtained from the induced voltage of the opposite phase, so that the accurate current value flowing through the parallel conductor 22, that is, the current wiring duct 1 The load capacity can be detected. Further, even when the noise component fluctuates and the detection value of the air-core coil 33 fluctuates, by taking the difference in the induced voltage between the first coil 33A and the second coil 33B, It is possible to prevent wobbling.

  Moreover, since the air-core coil 33 is used as means for detecting the load capacity of the wiring duct 1, a detection value with high linearity (linearity) can be obtained. That is, as a means for detecting the load capacity of the wiring duct 1, when a coil body provided with a magnetic material such as an iron core is used, if the value of the current flowing through the parallel conductor 22 increases, the detected value becomes a certain current value. Is saturated and detection is impossible in the range where the load capacity of the wiring duct 1 is high. However, by using the air-core coil 33, an accurate detection value can be obtained even when the load capacity of the wiring duct 1 reaches a high range. Can be obtained.

  Furthermore, when the opening 1a of the wiring duct 1 is small and the space between the parallel conductors 22 is narrow, it is necessary to use a small air-core coil 33, and the detected value of the air-core coil 33 is a small value. In addition, since amplification is performed by the amplifying unit 52, when the noise component of the detection value of the air-core coil 33 is large or when the sensor cable 36 is long, it is affected by noise superimposed or radiated on the sensor cable 36. Even so, the noise can be reduced.

  Furthermore, when an analog signal is transmitted to the display unit 60 via the sensor cable 36, noise proportional to the length of the sensor cable 36 is added to the analog signal. By performing D conversion, noise resistance can be improved, and the sensor cable 36 can be lengthened to increase the distance between the load capacitance detector 3 and the display unit 60.

  The above-described embodiment is an example of the present invention. For this reason, the present invention is not limited to the above-described embodiment, and various modifications can be made depending on the design and the like as long as the technical idea according to the present invention is not deviated from this embodiment. Of course, it is possible to change.

It is a perspective view showing the state where the load capacity detector to which the present invention is applied is attached to the wiring duct. It is sectional drawing of a wiring duct when the load capacity detector to which this invention is applied is attached to the wiring duct. It is a perspective view when attaching a load capacity detector to which the present invention is applied to a wiring duct, It is a disassembled block diagram of the load capacity detector to which the present invention is applied. It is sectional drawing of the air-core coil which is a voltage detection means. It is a functional block diagram for displaying the detection value of the load capacity detector to which the present invention is applied. It is a figure for demonstrating the technique which arrange | positions a clamp meter to the power wire connected with an alternating current power supply in the past, and detects load capacity. It is a figure for demonstrating the technique which connects an ammeter and detects load capacity conventionally. It is a figure for demonstrating the technique which detects load capacity from the breaker inside a distribution board in the past. It is a figure for demonstrating the technique which detects and displays load capacity in the past.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wiring duct 2 Outlet part 3 Load capacity detector 11 Feed-in part 21 Mounting part 22 Parallel conductor 31 Sensor housing 32 Wiring duct fixing | fixed part 33 Air core coil 34 Coil accommodating part 35 Sensor board 36 Sensor cable 37 Cable fixing | fixed part 38 Control circuit 39 Lead wire 41 Coil bobbin 51 Constant power supply 52 Amplifying unit 53 A / D conversion unit 54 Calculation unit

Claims (2)

A load capacity detector that detects a load capacity of a wiring duct in which positive and negative parallel conductors are arranged inside a case in which an opening is formed on one side surface,
A coil that is inserted into the case from the opening and is disposed at a substantially central position between the parallel conductors, and generates an induced voltage having an opposite phase by a magnetic flux generated as a current flows through the parallel conductors. Two voltage detectors connected in series, the coil is covered with an insulator, and a constant power source for applying a constant voltage to the connecting portion of the two coils is connected ;
A detecting means comprising a locking means for detachably locking the voltage detecting means to the peripheral edge of the opening of the case;
An output means for outputting the load capacity of the wiring duct determined according to the voltage detected by the voltage detection means to a display means for displaying the load capacity;
The detection means comprises amplification means for differentially amplifying each voltage induced in each coil in the voltage detection means, and A / D conversion means for discretizing the amplified voltage, and the output means A load capacity detector for a wiring duct, wherein the discretized voltage value is output to the display means. The coil is Ri Oh an air-core coil, the coil is covered with an insulator, according to claim 1, characterized in that the constant power source for applying a constant voltage to the connection portion of the two coils are connected Load capacity detector for wiring ducts.

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