JPS6325306B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic power meter.

The configuration of this type of electricity meter is shown in FIG. In the figure, 1 is a commercial power source, 2 is a load connected to the commercial power source 1 via a 3-wire distribution line 3, 4,
5 is a voltage transformer for detecting the phase-to-phase voltage of the distribution line 3; 6 and 7 are current transformers for detecting the current consumption of each phase of the distribution line 3. Reference numeral 8 denotes a measurement main unit, which includes a power amount measurement circuit 9 and a DC power supply 10 for driving the measurement circuit 9. 11 to 13 are voltage side terminals, and 14 to 17 are current side terminals.

The measurement circuit 9 is constructed as shown in FIG. That is, in the same figure, 21 and 22 are voltage and current input terminals, and 23 is both input terminals 2.
a multiplier for multiplying input signals from 1 and 22, 24;
25 is a frequency divider connected to the voltage/frequency converter 24, 26 is a counter circuit, and 27 is a power amount display that displays the output from the counter circuit 26. vessel, 28
is an operation indicator that blinks to indicate the power measurement status, and uses a light emitting diode or the like. A display section 29 is constituted by the above-mentioned display devices 27, 28, etc.

Next, the operation of the above configuration will be explained with reference to FIGS. 1 and 2.

As power is supplied from the commercial power source 1 to the load 2, a voltage signal _eV proportional to the load voltage on the distribution line 3 is transmitted to the voltage input terminal 2 by the voltage transformers 4 and 5.
1, and a current signal _{e I} proportional to the amount of consumed current flowing through the distribution line 3 by current transformers 6 and 7.
is input to the current input terminal 22. The multiplier 23 multiplies the voltage signal _eV and the current signal _eI to obtain a voltage signal proportional to the instantaneous power on the distribution line 3.
e ₀ = K・e _V・e _I (where K is a constant) is sent to the voltage/frequency converter 24, and the voltage/frequency converter 2
4 outputs a pulse train signal f ₀ having a frequency corresponding to the signal e ₀ described above. This signal f ₀ is frequency-divided by a frequency divider 25 and sequentially counted by a counter circuit 26. The counter output from the counter circuit 26 is input to the power amount display 27, and the power consumption amount is displayed on this display 27 in an integrated manner. During the measurement operation, the operation indicator 28 receives the output from the frequency divider 25 and operates according to the voltage/frequency characteristic a shown in FIG. 3, flashing to indicate that the measurement operation is in progress.

However, in the above configuration, it is necessary to rely on the blinking operation of one operation indicator 28, that is, one light emitting diode, to determine whether or not the measurement operation is in progress. When outputting, the blinking cycle of the display 28 becomes too short and becomes difficult to see visually.On the other hand, if the blinking of the display 28 is set to a level that is visible in this high load state, it will correspond to a low load. When the low frequency pulse train is output, the display 28
The flashing cycle is too long, forcing us to spend a long time checking the measurement operation at low loads.

This invention was made in order to eliminate the above-mentioned drawbacks of the conventional technology, and it sequentially blinks a plurality of operation indicators at a speed proportional to the frequency of the pulse train from the voltage/frequency converter, thereby providing control over the entire load range. The purpose of the present invention is to provide an easy-to-use power consumption meter that can easily and quickly grasp the measurement operation status.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 shows an example of a watt-hour meter according to the present invention, and the same parts as in FIGS. 1 and 2 are denoted by the same reference numerals, and the explanation thereof will be omitted.

In the figure, 40 ₁ to 40 _o are a plurality of operation indicators, and in this embodiment, light emitting diodes are used. For example, as _shown in _FIG . They are arranged in a ring to surround a power amount display 27 made up of segment display elements. Reference numeral 41 denotes an operation indicator drive circuit connected to the voltage/frequency converter 24 via the frequency divider 25, which includes, for example, a counter circuit 411 that counts the pulse train from the frequency divider;
The output from 1 is decoded and the operation indicator 4
It consists of a decoding circuit 412 that sequentially flashes 0 ₁ to 40 ₈ for each pulse.

In the above configuration, the pulse train corresponding to the load amount from the voltage/frequency converter 24 is frequency-divided and input to the drive circuit 41 as the electric power measurement operation is performed. The frequency-divided pulse train is sequentially counted. A decoding circuit 412 receiving the output from the counter circuit 411 outputs the output from the counter circuit 411.
For every one count operation _of
0 ₈ flash in sequence. For example, when the load is low, the conventional display blinks at a cycle of 20 seconds, but by using the eight indicators 40 ₁ to 40 ₈ ,
Since each of the operation indicators 40 ₁ to 40 ₈ blinks in sequence at a cycle of 20/8 seconds, the measured operation status can be confirmed in a short time even under the low load.

Of course, the operation indicators 40 ₁ to 40 _o may be arranged as shown in FIG. 6, and by increasing their number, visibility can be further improved. The devices 40 ₁ to 40 _o are not limited to light emitting diodes, and other optical display elements such as lamps can be used as appropriate.

As described above, the present invention sequentially blinks a plurality of operation indicators at a speed proportional to the frequency of the pulse train from the voltage/frequency converter, so that the blinking period under a constant load is the same as that of the conventional one. In this case, compared to the conventional method, the blinking cycle at low load is shortened, and the measurement operation status can be visually confirmed in a short time. Therefore, it is possible to improve the visibility of the measurement operation display over the entire load range.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the configuration of a conventional watt-hour meter, Fig. 2 is a block diagram of the measurement circuit in the watt-hour meter of Fig. 1, and Fig. 3 is a characteristic diagram showing the correlation between voltage and frequency. FIG. 4 is a block diagram of a measuring circuit in an example of the watt-hour meter according to the present invention, FIG. 5 is a plan view showing an arrangement of operation indicators, and FIG. 6 is a plan view showing another arrangement of operation indicators. It is a diagram. 23... Multiplier, 24... Voltage/frequency converter, 40 ₁ to 40 _o ... Operation indicator, 41... Operation indicator drive circuit. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A multiplier that multiplies a voltage signal proportional to the load voltage by a current signal proportional to the consumed current, and a voltage/frequency converter that receives the output from the multiplier and outputs a pulse train having a frequency proportional to the output. ,
A frequency divider connected to this voltage/frequency converter,
A plurality of blinking operation indicators that use the pulse train from this frequency divider as a blinking drive signal source, a counter circuit that sequentially counts the pulse train, and an output from the counter circuit that causes the plurality of blinking operation indicators to count once. A power meter equipped with an operation indicator drive circuit that causes the operation indicator to blink sequentially.