JP2003107108A - Current or power sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a current or power sensor capable of measuring current or power not for conductor of a wire one by one but by grasping cords and cables as they are with a current transformer, dispensing with interruption of power supply to an electrical equipment by pulling out a plug from a plug socket, dispensing with cutting-open of the wire for measurement, and having a small measurement error. SOLUTION: This current or power sensor is constituted while including a U-shaped core having a detection coil wound thereon, a holding fixture for holding the wire in the middle of a magnetic pole so that a magnetic flux generated therefrom becomes maximum in the magnetic pole direction, an amplifier for amplifying an output signal of the detection coil, and a phase- shifting amplifier for shifting the phase of the output signal by about 90 degrees.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention simply measures the internal two-core reciprocating conductor current of a power cord or power cable of an electric device and measures the current to easily measure the current consumption and electric power of the electric device. , Technology for measuring current and electric power in homes and factories without interrupting power supply to electrical equipment.

[0002]

2. Description of the Related Art Conventionally, in order to measure the current consumption and power consumption of electric equipment, generally, the plug of the power cord is temporarily removed from the outlet, the power is turned off, and the current or wattmeter is inserted into the outlet. Connect the plug of the electric device to the load side through the cable and reconnect it, or separate the inner two-core conductors of the power cord separately and attach a grasping current transformer to any one conductor. It was attached and measured. Further, as another method, as an attempt to measure the current while keeping the power cord, there is “Patent No. 2555264: Current sensor for reciprocating electric wire” which was invented by the present inventor.

[0003]

However, in the above-mentioned method of installing a current meter or a wattmeter between the outlet and the plug of the electric device, it is necessary to remove the plug from the outlet once, and the operation of the electric device is interrupted. In the method using the grasping type current transformer, it is necessary to cut the coating of the electric wire, so the safety and appearance after measurement,
There was a problem with the workability of measurement. In addition, the above-mentioned “Patent No.
In the method by "2555264", there is a large measurement error due to the positional relationship between the detection coil and the conductor of the electric wire, and the coil inductance causes a power measurement error due to the phase shift. Also, the impedance impedance causes a large frequency error. I couldn't share it. In addition, the voltage required for power measurement had to be connected to a voltage terminal separately.

Therefore, in the present invention, the electric current or the electric power can be measured by grasping the cord or the cable as it is with the current transformer instead of the electric wires one by one, and the plug can be unplugged from the outlet to interrupt the power supply of the electric device. It is an object of the present invention to provide a current or power sensor which does not need to be cut and which does not need to cut an electric wire for measurement and has less measurement error.

[0005]

In order to achieve the above-mentioned object, in the present invention, a U-shaped iron core around which a detection coil is wound, and a magnetic flux generated by a multi-core electric wire in the middle of the magnetic pole A holding tool that holds it in the maximum direction,
The present invention provides a current or power sensor including an amplifier for amplifying an output signal of the detection coil and a phase shift amplifier for shifting the phase of the output signal by about 90 degrees.

Next, the holder has an elastic member for holding the multi-core electric wire having a thickness in an arbitrary range with respect to a positioning support arranged on the U-shaped iron core side. Provides a current or power sensor with a part that regulates rotation so that the direction connecting the conductors of the double-core wire is orthogonal to the direction between the magnetic poles of the U-shaped iron core when the cross-section of the wire is flat. It was done.

Further, the voltage of the conductor with respect to the ground is detected as a voltage between conductors through the electrostatic capacitance between the metal portion arranged in the vicinity of the conductor and the conductor of the conductor, and the voltage between the conductors is detected. There is provided a current or power sensor including means for multiplying or synchronously rectifying a signal on the output side of the phase shift amplifier by a signal corresponding to a voltage.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows an embodiment of the present invention.
The detection coil 2 is wound around the U-shaped iron core 1, and the electric wire 3 including the reciprocating conductors 4 and 5 is interposed between the magnetic poles of the iron core 1 and the holder 6
And is held by the support 6 '. Arranged so that the line connecting the reciprocating conductors 4 and 5 is perpendicular to the line connecting the two magnetic poles, and between 4 and 5 there is a large amount of flat magnetic flux parallel to the conductor from right to left in the figure. Occur and these penetrate through the core 1.

FIG. 5 shows this state, and a magnetic flux 22 from between the conductors 4 and 5 is generated by a current flowing through the conductors 4 and 5 and penetrates through the iron core 1. An electromotive force corresponding to the magnetic flux is generated in the coil 2. In FIG. 1, 6 is a non-magnetic holder,
Reference numeral 6'denotes a support tool arranged on the iron core 1 side to position and hold the electric wire 3 as described above. Reference numeral 7 is a holder cover, and 8 is an iron core cover, which are stopped by grasping the electric wire 3 by means of stoppers 10 and 11 at both ends. In addition, 9 is an elastic cushioning material, which presses the electric wire 3 from above in the drawing through the holder 6 to the supporting tool 6'on the side of the iron core 1 to bring them into close contact.

Next, in the figure, 12 (D) is an amplifier for amplifying the output signal of the detection coil 2, the output of which is phase-shifted by the phase-shifting amplifier 13 (θ) by about 90 degrees, and the output of the detection coil 2 is approx. The voltage phase induced by 90 degrees is corrected. Reference numeral 14 (K) is a variable amplifier that switches the amplification degree according to the type of electric wire, and is also used as a scale calibration. If accuracy is not so important, it may be fixed. The current value information can be output only from the outputs of the 14 variable amplifiers (K).

Reference numeral 15 (X) is a multiplier, which synchronously rectifies the signal from K by a signal corresponding to the power supply voltage from a conductor 18 such as a metal or a conductive material provided near the electric wire 3 (approximate to AC multiplication). Alternatively, it multiplies and outputs a signal corresponding to the power. Note that 18 may be used also as the iron core 1, and the power source voltage is detected in a non-contact manner via the capacitance between the iron core 1 and the conductor. 16 (F) is a filter for smoothing the output of 15 to obtain a DC component. This output is a digital voltmeter 17 (D
Read in VM). Magnetic flux between conductors 22 (Fig. 5)
Is proportional to the wire current, it is clear that the sensitivity of the above-mentioned amplifier can be adjusted to calibrate the scale as a current value or power value.

FIG. 2 shows another embodiment of the holder 6, which has elastic members, that is, spring plates 19 and 20 attached to the holder 6, and has a structure in which the electric wire 3 is sandwiched and held from both sides. If the wire 3 is flat as shown in FIG.
The portions of the wires 20 and 20 that come into contact with the electric wire regulate the rotation of the electric wire 3 by sandwiching the parallel portion of the outer sheath of the electric wire. In the flat electric wire, the wire connecting the conductors 4 and 5 is a U-shaped core 1. The magnetic flux generated by the currents flowing through the conductors 4 and 5 is held so as to be the strongest in the direction of the magnetic poles.

FIG. 3 shows a circular electric wire 21 provided on the holder shown in FIG.
This is an example in the case of holding. In this case, since the outer shape of the wire is round, there is no correlation between the direction of the magnetic flux and the outer shape, and accurate measurement cannot be performed with the wire held. Therefore, after the electric wire 21 is held by the holding tool, the electric wire 21, the holding tool 6 and the U-shaped iron core 1 are mutually rotated, and measurement is performed at a position where the output value becomes maximum (the direction between the road lines and the direction between the magnetic poles is vertical). I am trying.
The thickness of the wire can be adjusted within an appropriate range by the elasticity of the spring plates 19 and 20.

Further, in FIG. 4, the holder 6 is made of a material such as rubber or sponge which can be deformed uniformly by an external pressure, and the holder 6 can be held as shown in the figure so that the electric wire 3 between the holder 6 and the holder 6'can be held at the center. This is another example in which a V-shaped recess is provided in both the support and the support tool 6'to accommodate both flat and round electric wires. That is, in the case of a flat electric wire, the rotation is restricted and held between the apexes of the V-shape, and with the round electric wire, the electric wire is held by the inner surface of the V-shape and the electric wire can be rotated. It was done. In this holder 6, the V-shaped portion may be made of a hard material instead of an elastic material, and the holder 6 may be made of both an elastic material and a hard material. In the above description, the electric wire has been described as a multi-core electric wire through which a reciprocating current flows, but it is possible to measure even by grasping only one wire as in the conventional case.

As described above, in the embodiment of the present invention, the electric wire is U
The magnetic flux generated by the wire is held between the two magnetic poles of the V-shaped iron core so that the magnetic pole penetrates the most magnetic pole, and the phase of the output voltage of the iron core detection coil is made in phase with the power supply voltage by the phase shifter.
Synchronous rectification (or multiplication) by non-contact voltage detection if necessary
Then, the current power can be obtained. The detection by the U-shaped iron core may be performed by providing a plurality of outputs at appropriate positions and angles and combining the outputs (AND or OR addition) so as to correspond to any position of the electric wire. For example, FIG. 6 shows an example thereof, in which two identical U-shaped iron cores 1 are made to face each other and the detected voltages of the coils 2 are combined, and the influence of the positional change of the electric wire 3 in the vertical and horizontal directions is further reduced. Further, in the example of FIG. 6, the holding tool and the supporting tool can hold the electric wire by providing the supporting tool in one U-shaped iron core and the holding tool in the other iron core.

[0016]

As described above, according to the present invention, the current or the power can be measured by grasping the cord or the cable as it is with the current transformer instead of the electric wires one by one, and the plug can be unplugged from the outlet. It is possible to provide a current or power sensor that does not need to interrupt the power supply of an electric device, does not need to cut an electric wire for measurement, and has less measurement error.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention.

FIG. 2 is another embodiment of the holder of the present invention.

FIG. 3 is an explanatory diagram when a round code is applied to FIG. 2.

FIG. 4 is another embodiment of the holder of the present invention.

FIG. 5 is an explanatory diagram of magnetic flux

FIG. 6 is another embodiment of the present invention.

[Explanation of symbols]

1-U-shaped iron core 2 ... Detection coil 3 ... code 4,5 ... Conductor in the cord 6 ... Retainer 6 '・ ・ ・ ・ ・ Support tool 7: Holder cover 8: Iron core cover 9 ... Cushion material 10,11 ・ ・ ・ ・ ・ Stoppers 12 ・ ・ ・ ・ ・ Amplifier 13 ・ ・ ・ ・ ・ Phase shift amplifier 14 ・ ・ ・ ・ ・ Variable amplifier 15 ・ ・ ・ ・ ・ Multiplier 16 ・ ・ ・ ・ ・ Filter 17 ・ ・ ・ ・ ・ Digital Voltmeter 18 ... conductor 19,20 ・ ・ ・ ・ ・ Spring leaf 21 ・ ・ ・ ・ ・ Round cord 22 ... Magnetic flux

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Claims (3)

[Claims] 1. A U-shaped iron core around which a detection coil is wound, a holder for holding an electric wire in the middle of the magnetic pole so that the magnetic flux generated by the electric wire becomes maximum in the direction of the magnetic pole, and the output of the detection coil. A current or power sensor comprising an amplifier for amplifying a signal and a phase shift amplifier for shifting the phase of the output signal by about 90 degrees. 2. The holding member has an elastic member for holding the electric wire having a thickness in an arbitrary range with respect to a positioning support member arranged on the U-shaped iron core side, and the elastic member has an electric wire. When the cross section of the electric wire has a flat shape, it has a portion for restricting rotation so that the direction connecting the conductors of the electric wire is orthogonal to the direction between the magnetic poles of the U-shaped iron core. Or power sensor. 3. An inter-conductor voltage is detected through a capacitance between a metal part arranged in the vicinity of the electric wire and a conductor of the electric wire,
3. The current or power sensor according to claim 1, further comprising a multiplier for multiplying a signal on the output side of the phase shift amplifier by a signal corresponding to the voltage between the conductors or for synchronous rectification.