JP2000074946A - Watthour meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make exchangeable or removable wires in a hot-line state even in the case of wrong wiring by connecting a current transformer part where the secondary output of the current transformer is connected by a detachable connector and a watthour meter part with current and voltage input parts using an exclusive current wiring cable whose both ends have connectors. SOLUTION: A current measuring transformer part 2 for measuring current is arranged at the R and T phases of an electric circuit 1 to be measured that is a three-phase AC electric circuit, and the current transformer part 2 is connected to a current input part 41 of the watthour meter part 4 using an exclusive current wiring cable 3. In the current transformer part 2, a current transformer 21 for R phase and a current transformer 22 for T phase are connected to an easily detachable connector 23, and at the same time, diodes 211 and 221 are provided in opposite directions. Further, the surfaces of the current transformer 21 and 22 are marked by red and blue phase colors for the current transformers for R phase and T phase, respectively, and a K side is marked by a power supply side polarity identification for easily identifying the power supply side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a three-phase or single-phase
The present invention relates to an electric energy meter installed in a line AC electric circuit.

[0002]

2. Description of the Related Art FIG. 5 is a configuration diagram for measuring and measuring current and electric energy using a conventional ammeter, watt hour meter and current transformer. Hereinafter, the configuration will be described with reference to the drawings.

When measuring and measuring the current and electric energy of the three-phase or single-phase three-wire AC circuit 1, separate current transformers 24 and 25 are provided for two phases, and the wiring 34 is connected to the current transformer. Is connected to the current input terminal 51 of the watt-hour meter 5 via the wiring 34, and connected to the watt-hour meter 5 via the switch 36 via the wiring 35 so that each phase voltage is input to the voltage input terminal 52. It had been.

[0004]

With respect to the installation of the current transformer, it is important that the installation phase and the K side / L side are correctly aligned. Next, regarding the wiring between the current transformers 24 and 25 and the watt hour meter 5, the polarities k and l of the secondary outputs of the current transformers 24 and 25 are correctly wired according to the input terminal symbols of the watt hour meter 5. This is very important. However, when the current transformers 24 and 25 and the watt hour meter 5 are actually installed and wired on site, it is not easy to correctly install and wire them, and the mistake also causes the load to be moved. An electric watt-hour meter is discovered only after indicating the measurement, but in many cases a power failure cannot be made after the construction is completed, and it is very difficult to correct the wrong connection if there is a mistake.

The present invention has been made to solve the above-mentioned problem, and has a configuration in which there is little error in the installation of a current transformer, and there is no mistake in wiring of a current circuit between the current transformer and a watt hour meter. It is another object of the present invention to provide a method for protecting the secondary opening of the current transformer even when there is a wiring error, and making it possible to easily correct the error with a live wire.

[0006]

According to the present invention, a diode is provided between the secondary output circuits of two independent current transformers provided in two phases of a three-phase or single-phase three-wire AC circuit. In addition to the opposite direction, on the surface of the current transformer,
The phase identification and the polarity identification on the power supply side are performed.
A current transformer unit connected to the next output by one easily detachable connector; a watt hour meter unit having a current input unit and a voltage input unit constituted by the easily detachable connector; It consists of a dedicated current distribution cable with connectors at both ends for connecting the meter section.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention has the above-described structure,
Current transformers can be easily and correctly arranged on the R and T phases of the wire under test, and the secondary-side wiring of the two current transformers is used as a single connection part to connect the power meter to the power meter. Since the configuration is such that the connection can be made by the parts, there is an effect that the wiring work can be easily performed without errors. Further, since the electric energy meter includes the current transformer unit, the electric energy meter unit, and the wiring cable unit, it has an operation of correcting an error in a live state.

Hereinafter, the present embodiment will be described with reference to FIGS.
This will be described with reference to FIG. (Embodiment) As shown in FIG. 1, current measuring current transformers 2 are arranged on the R and T phases of a circuit 1 to be measured, which is a three-phase AC electric circuit, and the current transformers 2 and a watt hour meter are arranged. 4 between the current input section 41 and the dedicated current distribution cable 3 and the current transformer section 2
Connect the secondary outputs of the R-phase current transformer 21 and the T-phase current transformer 22 with the output characteristics k and l to one easily removable connector 23, and furthermore, Between the secondary outputs of each current transformer, a diode 211,
As shown in FIG. Next, FIG.
As shown in the figure, on the surface of each of the current transformers 21 and 22, the R-phase current transformer 213 for the R-phase current is clearly identified by the red phase color and the power supply side is easily identified on the K side. The polarity identification 212 for each power source and the current transformer for T-phase
A power-supply-side polarity identification 222 for facilitating power-supply-side discrimination is applied to each of the blue phase colors 223 and the K-side for clear T-phase expression.

The watt-hour meter section 4 has a current input section 41 as a connector and a voltage input section 42 as a connector or a screw terminal. On the other hand, the wiring of the measured circuit 1, the current transformer 2 and the watt-hour meter 4 is
The current input section 41 of the watt hour meter section 4 is connected to the current input section 41 by a dedicated current wiring cable 3, and the voltage input section of the watt hour meter section 4 inputs each phase voltage from the electric circuit 1 to be measured via the switch 36. Is what is done. Here, the dedicated current distribution cable 3 is provided at its both ends with connectors 31 and 33 which match the connector 23 of the current transformer section 2 and the current input section connector 41 of the watt hour meter section 4.

The diodes 211 and 221 in the current transformer section 2 in the above configuration are provided on the current transformer side for the purpose of protecting the current transformers 21 and 22 at the time of secondary opening, and are connected in a normal state. When it is set, the current transformer output voltage is provided to be used in a high resistance region having a diode characteristic.

Next, a case where the polarity of the current transformer is wrong when the current transformer is installed on the electric circuit to be measured in the above configuration will be described with reference to FIG.

FIG. 1 shows a state in which the polarity of a current transformer installed in the T phase of a measured circuit is incorrectly installed on the load side of the measured circuit.

In such a case, since each of the current transformers of the current transformer section 2 is protected by a diode when the secondary is opened, the dedicated current distribution cable 3 can be used without interruption of the power to the measured circuit 1. Is removed from the current transformer section 2 and, in response to the polarity k, l of the current transformer 22 having been reversed, the exclusive polarity is reversed at the connection portion between the connector 31 and the cable 32 of the dedicated current distribution cable 3. By reconnecting the current transformer unit 2 and the watt hour meter unit 4 using the current distribution cable 7, the wiring can be easily replaced. Therefore, a safe operation can be easily performed without a power failure of the measured electric circuit.

A case where the current transformer is incorrectly installed on the electric circuit to be measured by mistake will be described with reference to FIG.

FIG. 1 shows a state in which a current transformer to be installed in the T phase is installed in the S phase. The input of the current sent from the current transformer unit 2 to the wattmeter unit 4 through the dedicated current distribution cable 3 is T
Since the current transformer 22 to be installed in the phase is installed in the S phase, T
S-phase current information is sent as a phase component. For this reason, the phase of the input current and the input voltage are shifted from each other, so that the power amount cannot be measured correctly. However, if the switch 36 is opened, the voltage input cable 35 to the watt hour meter unit 3 can be measured without power failure of the measured circuit 1. , The wiring of the T phase and the S phase can be easily replaced, and the electric energy can be measured correctly.

[0016]

As is apparent from the above description, the electric energy measuring device of the present invention comprises a current transformer section, an electric energy meter section, and a dedicated current wiring cable. By using an easy connector, there is an effect that the wiring operation can be easily and definitely performed.

In the current transformer section, since the phase of the current transformer is identified on the surface of each current transformer and the polarity of the power supply is identified, the current transformers can be easily connected to the R and T phases of the wire to be measured. Can be arranged correctly, and the secondary outputs of the two current transformers are connected by one easily detachable connector, so that the work of wiring the secondary output can be performed without error. Also, since the electric energy meter is composed of the current transformer, the electric energy meter, and the dedicated current wiring cable, the current transformer may be incorrectly installed, or the electric energy meter may be maintained or inspected. The wiring can be safely and easily changed or removed in the live state.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a current transformer, a dedicated cable, and a watt hour meter according to the present invention.

FIG. 2 is a front view of a current transformer unit according to the present invention.

FIG. 3 is an explanatory view showing an incorrect polarity direction of a current transformer.

FIG. 4 is an explanatory view showing an incorrect installation phase of a current transformer.

FIG. 5 is a configuration diagram of a current transformer, a wiring cable, and a watt hour meter in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Measured electric circuit 2 Current transformer part 21 R phase current transformer 211 Diode 212 Polarity identification of R phase power supply side 213 R phase phase color identification 22 T phase current transformer 221 Diode 222 T phase power supply side Polarity identification 223 R-phase color / color 23 Connector 24 R-phase current transformer 25 T-phase current transformer 26 Terminal block 3 Dedicated current wiring cable section 31 Connector 32 Cable 33 Connector 34 Current input wiring 35 Voltage input wiring 36 Switch 4 Watt hour meter section 41 Current input connector 42 Voltage input connector 5 Watt hour meter 51 Current input terminal 52 Voltage input terminal 7 Dedicated wiring cable

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Tomohiro Fujii 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. A diode is provided in opposite directions between secondary output circuits of two independent current transformers provided in two phases of a three-phase or single-phase three-wire AC circuit, and a surface of the current transformer is provided with: A current transformer section that performs phase color identification and polarity identification on the power supply side and connects the secondary output of the current transformer with one easily removable connector, and a current input section configured by the easily removable connector. A watt hour meter comprising a watt hour meter section having a voltage input section and a dedicated current wiring cable having connectors at both ends for connecting the current transformer section and the watt hour meter section.