JPH026373Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an electronic watt-hour meter, and particularly to the structure of a case for picking up the output pulses of the meter in an electrically insulated state.

[Technical background of the invention and its problems] Figure 1 shows the basic configuration of an electronic watt-hour meter. In the figure, and are the input load voltage and current, 1 is an auxiliary transformer, and 2 is an auxiliary current transformer, which converts each into a low-level signal. 3 is a power-voltage converter which multiplies the signals from the auxiliary transformer 1 and the auxiliary current transformer 2 and converts the product into a voltage proportional to the power. A voltage-frequency converter 4 integrates the voltage proportional to the electric power from the power-voltage converter 3 and converts it into a pulse frequency proportional to the amount of electric power. 5 is a frequency divider which weights the amount of power per pulse by dividing the output pulse frequency of the voltage-frequency converter, and converts it into the required transmission pulse and display drive pulse. do.
Reference numeral 6 denotes a counting display section which counts the driving pulses weighted by the frequency divider 5 and displays the integrated amount of electric power.
Reference numeral 7 denotes an output terminal, which is a terminal for outputting test pulses for the electronic watt-hour meter, and is connected to the input section of the frequency divider 5 or after a suitable frequency division stage.

The characteristics of the electronic watt-hour meter shown in FIG. 1 are usually measured by a comparison test as shown in the second example. In Fig. 2, 11 is the test meter, 12
is a pulse output proportional to the amount of electric power corresponding to the output from output terminal 7 in Fig. 1, 13 is a standard watt-hour meter with a known error, 14 is an output pulse proportional to the amount of electric power of the standard watt-hour meter, and 15 is a pulse output proportional to the amount of electric power of the standard watt-hour meter. , pulse output 12, 14
counter 15a and counter 15b, respectively.
It is a kind of preset counter that stops the counting of the counter 15b when the counter 15a reaches a predetermined count value. 16 is an imaginary load power supply that generates a load current, which corresponds to voltage. Here, the voltage is connected in parallel and the current is connected in series, and since the test meter 11 and the standard watt-hour meter 13 operate under the same conditions, the pulse outputs 12 and 14, which are their respective outputs, can be compared using the counter 15. The error of the test meter 11 can be determined by .

When manufacturing the meter, there is no particular problem because the pulse output of the test meter 11 can be directly counted by the counter 15, as shown in FIG. However, after an electronic watt-hour meter has been installed on-site, for example on a power distribution board, testing requires a worker to enter the back of the power distribution board or inside a narrow space and make the connections as shown in Figure 2, which is difficult. It is equally dangerous.

For this reason, a method was adopted in which the pulse corresponding to the pulse output 12 in FIG. 2 was displayed using a light emitting diode. The configuration of the electronic watt-hour meter 31 in this case is explained in the third example.
As shown in the figure. In FIG. 3, 30 is a light emitting diode. In this method, the light emitting diode 30 is effective for visual checking, but it is not practical to detect the minute blinking light of the light emitting diode 30 with a phototransistor or the like and use this as a substitute for the pulse output 12 in FIG. It turned out that it was inefficient. That is, the biggest drawback is that it takes time to align the light emitting diode 30 and the phototransistor as a light receiving element.

[Purpose of the invention] This invention allows for easy error testing of electronic watt-hour meters that use light-emitting elements such as light-emitting diodes that flash at a pulse frequency proportional to the amount of electricity measured, while the electronic watt-hour meter remains attached to the switchboard. Another object of the present invention is to provide an electronic watt-hour meter that can be implemented reliably.

[Summary of the invention] The invention consists of an auxiliary transformer that converts the load voltage into a low-level signal, an auxiliary current transformer that converts the load current into a low-level signal, and a system that multiplies the outputs of these two transformers. The power converted into a voltage proportional to the product −
A voltage converter, a voltage-frequency converter that integrates the output voltage of the power-voltage converter and converts it into a pulse frequency proportional to the amount of power, a count display section that displays the integrated amount of power, and a frequency converter that integrates the output voltage of the power-voltage converter and converts it into a pulse frequency proportional to the amount of power. In the electronic watt-hour meter, a convex lens-like convex portion is provided on the optical axis of the light-emitting element in a display window on the front surface of the case that houses each of the functional units. A light receiving window having a concave surface corresponding to the convex surface of the convex part and into which the convex part can be fitted is provided on one surface of the light shielding case, and a light receiving element disposed coaxially with the light receiving window is built in. The intended purpose has been achieved by realizing an electronic watt-hour meter characterized in that a light receiver can be mounted with the light receiving window fitted into the convex portion.

[Embodiments of the invention] Hereinafter, embodiments of the invention will be described with reference to the drawings.

FIG. 4 and FIGS. 5a and 5b show an electronic watt-hour meter according to an embodiment of the present invention. Figure 4 is a front external view of the electronic watt-hour meter, where 40 is the case of the electronic watt-hour meter, 41 is the count display section, 42 is a light-emitting element such as a light-emitting diode, and 43 is a display made of glass or the like. The window 44 is a convex portion provided on the optical axis of the light emitting element 42 of the display window, and 45 is the outer frame of the display window. The convex portion 44 is formed in the shape of a convex lens at a location on the optical axis of the light emitting element 42 of the display window 43, as shown in FIGS. 5a and 5b.

Reference numeral 61 shown in FIG. 6 is a light receiver, which is a convex portion 4 provided in the display window 43 of the electronic watt-hour meter shown in FIG.
The convex portion 44 has a concave surface corresponding to the convex surface of the convex portion 44.
A light-receiving window 62 into which a light-shielding case 63 can be fitted is provided on one surface of the light-shielding case 63. Reference numeral 64 denotes a light receiving element such as a phototransistor, which is disposed coaxially with the light receiving window 62 in the light-shielding case 63.As shown in the figure, the light receiving window 62 is fitted onto the convex portion 44 of the electronic watt-hour meter. When the light emitting element 42 is attached, the light from the light emitting element 42 reaches the protrusion 44.
The distance from the light receiving window 62 and the focal length of the convex lens of the convex portion 44 are selected so that the convex lens focuses the light onto the light receiving surface of the light receiving element 64. 65 is a lead wire of the light receiving element 64, which is connected to guide the output signal of the light receiving element 64 to the counter 15a shown in FIG.

In the electronic watt-hour meter of the embodiment of the present invention configured as described above, when performing an error test, a light receiver 61 is installed in the display window 43 of the electronic watt-hour meter as shown in FIG. The light receiving window 6 of the light receiver is
2 are fitted together and installed. In this way, the light emitting element 42 of the electronic watt-hour meter blinks at a frequency corresponding to the input power, and this light is focused through the convex portion 44 of the display window 43 and is directed to the light receiver on the same optical axis. 61 through the light receiving window 62 of the light receiving element 6
The light is focused on the light receiving surface of 4 and received by the light receiving element 64,
The photoelectrically converted electrical pulse is guided to a counter 15a shown in FIG. Then, the error of the test meter is measured by comparing the counts of the counter 15b and the counter 15a, which count pulses from the standard watt-hour meter.

As described above, in the electronic watt-hour meter according to the present invention, the light-emitting element of the meter and the light-receiving element can be connected by fitting the light-receiving window of the light-receiving device into the convex portion provided on the light-receiving window located on the optical axis of the light-emitting element. Since the positional relationship between the two positions is uniquely determined, there is no need for wasted time in alignment. In addition, the convex lens-like convex part of the display window allows the concentrated strong light of the light emitting element to be input to the light emitting element of the light receiver, so minute blinking light from the light emitting element can be reliably measured, improving test accuracy. do. Furthermore, reliable error testing can be performed simply by attaching a light receiver to the front of the meter without removing the meter from the switchboard, making inspection of the meter easier and improving work safety.

Note that the present invention is not limited to the above-mentioned embodiments, and can be implemented with modifications as described below.

[a] In the embodiment shown in FIGS. 5a and 5b, the convex part 44 was made into a spherical shape, but as shown in FIGS. The shape of the light receiving window 62 of the light receiver 61 is also formed in the convex part 74.
It can be made into a shape having a prismatic surface portion 72 corresponding to the shape of. By doing so, the guiding performance between the convex portion and the light receiving window is improved, and the mounting of the light receiver on the display window of the electronic watt-hour meter becomes more stable.

[b] As shown in FIG. 8a and b, the display window 43
A concave portion 81 is formed coaxially on the inner surface of the convex portion 44,
It is also possible to bring the light emitting element 42 close to the display window 43 by inserting it into the recess 81. As a result, the distance between the light emitting element 42 and the light emitting element of the light receiver is shortened, and the light emitting element 42
It is possible to increase the reliability of light detection from

[c] As shown in FIGS. 9a and 9b, the display window 43
A protrusion 91 may be coaxially provided on the inner surface of the protrusion 44 . Thereby, the degree of convergence of light from the light emitting element 42 can be further increased.

[Effects of the invention] As described in detail above, according to the invention, in an electronic watt-hour meter, the position on the optical axis of a light-emitting element that blinks at a pulse frequency corresponding to the magnitude of the measured electric energy is detected. A convex lens-shaped convex part is provided in the display window of the type watt-hour meter, and the convex part can be fitted into a receiver equipped with a concave light-receiving window corresponding to the convex part, with the convex part fitted into the light-receiving window. By attaching it to the display window on the front of the electronic watt-hour meter, when performing an error test on the electronic watt-hour meter, you can simply fit the light-receiving window of the receiver into the convex part of the display window, and the meter will turn off. Since the positional relationship between the light emitting element and the light receiver is uniquely determined, there is no need for wasted time in alignment. In addition, the convex lens-shaped convex part of the display window allows the concentrated strong light of the light-emitting element to be input to the light-receiving element of the light receiver, so minute blinking light from the light-emitting element can be reliably measured, increasing the accuracy and reliability of the test. Improves sex. Furthermore, reliable error tests can be performed simply by attaching a light receiver to the front of the meter without removing the electronic watt-hour meter from the switchboard, making inspection of the electronic watt-hour meter easier and improving work safety. is achieved.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing the basic configuration of an electronic watt-hour meter, Figure 2 is an electrical connection diagram showing the connection of the meter when performing an error test on an electronic watt-hour meter, and Figure 3 is a diagram showing the connection of the meter when performing an error test on an electronic watt-hour meter. A block diagram showing the configuration of an electronic watt-hour meter having a function of displaying a pulse frequency corresponding to the measured electric energy, FIGS. 4 and 5 a and b show an electronic watt-hour meter according to an embodiment of the present invention, Figure 4 is a front external view of the electronic watt-hour meter, Figure 5a is a detailed front view of the convex part in Figure 4, Figure 5b is a sectional view of the convex part in Figure 5a, and Figure 6 is Fig. 5b shows a state in which a light receiver is attached to the convex part, Figs. 7a, b, and c show a modified example of the present invention; Figure b is a cross-sectional view of the convex part shown in Figure 7a, Figure 7c is a diagram showing the state in which the light receiver is attached to the convex part shown in Figure 7b, and Figures 8a and b are other views of the present invention. A modified example is shown, FIG. 8a is a front view of the convex part, and FIG. 8b is a front view of the convex part.
9a and 9b show other modifications of the present invention; FIG. 9a is a front view of the protrusion;
Figure b is a sectional view of the convex portion of Figure 9a. 1... Auxiliary transformer, 2... Auxiliary current transformer, 3...
power-voltage converter, 4... voltage-frequency converter,
5... Frequency divider, 6... Count display unit, 11... Test meter, 13... Standard watt-hour meter, 15... Counter, 30... Light-emitting diode, 40... Electronic watt-hour meter case , 41...Weighing display section, 42...
Light emitting element, 43...Display window, 44...Protrusion, 61
... Light receiver, 62 ... Light receiving window, 63 ... Light shielding case, 64 ... Light receiving element, 65 ... Lead wire, 74
...Convex portion, 74a...Spherical surface portion, 74b...Prismatic portion, 72...Prismatic surface portion, 81...Concave portion, 91...
Convex part.

Claims (1)

[Scope of utility model registration request] An auxiliary transformer converts the load voltage into a low-level signal, an auxiliary current transformer converts the load current into a low-level signal, and the outputs of these two transformers are multiplied and converted into a voltage proportional to the product. a power-to-voltage converter; a voltage-to-frequency converter that integrates the output voltage of the power-to-voltage converter and converts it into a pulse frequency proportional to the amount of electric power; a count display section that displays the integrated amount of electric power; In an electronic watt-hour meter comprising a light-emitting element driven by a pulse output proportional to A light receiving window having a concave surface corresponding to the convex surface of the projecting part and into which the projecting part can be fitted is provided on one surface of the light-shielding case, and a light receiving element disposed coaxially with the light receiving window. An electronic watt-hour meter, characterized in that a built-in light receiver can be attached with the light receiving window fitted into the convex portion.