JP2003004781A - Load device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a load device in which other loads, i.e., other used devices, will not be influenced, even when 40A at a comparatively large capacity is applied, when a voltage drop at a branch terminal of a low-voltage branch circuit, i.e., an internal resistance, is detected and in which the timing of a detector is adjusted easily, when a voltage in a load current is detected. SOLUTION: The load device comprises a means which is connected across branch terminals of the low-voltage branch circuit, so as to supply a prescribed load current, a timer which makes the load current in one cycle flow to the connected low-voltage branch circuit, a detection means which detects the voltage across the branch terminals corresponding to the load current and a trigger output means which is interlocked with the operation of the timer for driving the detection means, and the internal resistance across the connected branch terminals is obtained on the basis of detection result.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention reduces the internal resistance seen from the outlet of an indoor wiring circuit for home use, that is, a low-voltage branch terminal, with low power consumption and less influence on other connected devices. More specifically, the present invention relates to a load device capable of detecting, and more specifically, one cycle (20 mse) of load current between branch terminals in an outlet circuit.
c) In addition, unloaded voltage and, for example, 10A, 2
The voltage under load at 0 A, 30 A, and 40 A is detected, recorded on an oscillograph, for example, and the internal resistance seen from the outlet is calculated.

[0002]

2. Description of the Related Art In recent years, since electronic devices such as computers have been widely used, the adverse effect of voltage drop in indoor wiring has come to the surface. Most of the causes of the voltage drop are caused by the thickness and length of the wiring, the wiring route, the usage status of the load, the harmonics, etc., but for example, indoor wiring circuits for home use or power use, etc. Outlet,
That is, the wiring resistance (including contact resistance) of the low-voltage wiring is also one of the factors.

Therefore, there is an increasing demand for easily detecting the internal resistance value, that is, the voltage drop as seen from the outlet circuit and the branch terminal of the low-voltage wiring. Such a commercially available load device provided for the measurement is connected to the low-voltage branch terminal to, for example, 10A, 20A, 30A,
Some applied a load current of 40 A for 0.5 seconds.

[0004]

However, at the maximum of 40 A, the power drop monitoring may be activated due to the influence of the voltage drop, and other loads of the same system, that is, other equipment to be used may be affected. In addition, when recording on a handheld oscillograph at the time of load, it was difficult to adjust the timing during recording.

[0005]

The invention according to claim 1 is
Between the branch terminals of the low voltage branch circuit, a means for supplying a predetermined load current, a timer for flowing the load current for one cycle to the connected low voltage branch circuit, and the branch terminals corresponding to the respective load currents. A detection means for detecting a voltage and a trigger output means for driving the detection means in conjunction with the operation of the timer are provided, and the internal resistance between the connection terminals is obtained based on the detection result. Is a load device. By using such a load device, the voltage drop, that is, the internal resistance can be obtained by detecting the voltage between the branch terminals with almost no influence on the low voltage branch circuit.

According to a second aspect of the present invention, the detection means is
By detecting the voltage between the branch terminals, the voltage drop, that is, the internal resistance can be obtained. By using such a load device, by recording the voltage between the branch terminals corresponding to each load current, the voltage drop, that is, the internal resistance can be obtained from the recorded voltage.

According to a third aspect of the present invention, the load current supply means comprises a semiconductor relay. By using such a load device,
It is possible to reliably supply a predetermined load current.

According to a fourth aspect of the present invention, the timer comprises a first timer for setting a time for detecting a voltage before applying a load current and a second timer for applying the load current for one cycle. It is a load device characterized in that. With such a load device, the voltage in the unloaded state between the branch terminals and the voltage when a predetermined load current is applied can be reliably detected, so that the voltage drop between the branch terminals and the internal resistance can be easily obtained. be able to.

[0009]

1 is a block diagram showing an embodiment of the present invention.
The present invention will be described below with reference to the block diagram of FIG. Reference numeral 1 is a control power source having a power switch SW1, and this control power source 1 receives its terminal 2 by inputting AC100V.
It is configured to output 5 V of direct current (for semiconductor relay) and 6 V of direct current (for IC circuit) to the terminal 3. In addition, a capacitor (not shown) with a large capacitance is used so that the control power supply does not drop even if the voltage of AC100V drops at the time of detection.
It is designed to withstand c). Reference numeral 4 denotes a timer circuit, which has a detection start switch SW2, and although not shown, includes R and C for preventing chattering when the switch is turned on and off.

Reference numeral 6 denotes a first timer, which is composed of a resistor, a capacitor, and an IC circuit, which is not shown in detail, but uses a charging time by the resistor and the capacitor. The voltage before load application by the timer is measured (1 cycle), but since it is asynchronous to the commercial power supply, consider that half cycle waveform appears on the positive pole even when the trigger point is on the negative pole side. Therefore, a margin is provided, and it is possible to prevent malfunction due to chattering during the switch operation of the present invention. The time is determined by the multiplier of the capacitor and the resistance (charging time), and can be adjusted from about 10 msec to about 100 msec in this circuit. In the actual machine, it was set to 30 msec. 7 is a second timer, which has the same configuration as the first timer 6, but has a commercial frequency of 50.
The time setting is one cycle of Hertz, and it is adjusted to 20 msec in the actual machine. When the control power supply 1 is turned on, a timer described later may malfunction. Therefore, a general timer reset circuit 4a is provided so that the timer circuit 4 is reset when the power is turned on.

Reference numeral 10 denotes a semiconductor relay control unit, which is a semiconductor relay (solid state relay) (SSR) current value (1
0, 20, 30, 40A) selection and drive circuit. The semiconductor relay control unit 10 turns on and off at an AC voltage of 0V. In the circuit, diodes (not shown) are arranged in a matrix for selecting a current value, and terminals 11, 12, 13, and
14, and a current value is selected by a rotary switch (not shown). Reference numeral 16 is a dummy resistor portion, which is represented by one resistor as a whole.
Connect 5 W resistors in parallel (combined resistance 9.75 ohms,
25 W), and the same four circuits (10, 20, 30, 40 A) are provided.

Reference numeral 17 denotes a trigger output section, which is a first timer 6 (30 msec) and a second timer 7 (20 mse) via an OR circuit 18, as shown in the output timing chart of FIG.
50msec is output by C and R of c). The trigger output unit 17 is connected with a detection device 19, that is, an oscillograph recorder as a recording device for displaying and recording and outputting a voltage waveform,
As will be described later, as shown in FIG.
The detected voltage waveform is output and recorded based on the operation of. The detection device 18 is mainly composed of, for example, an OR-100E manufactured by Yokogawa Electric Co., Ltd., and the detected voltage is recorded and output on a recording sheet and displayed on the liquid crystal display surface. ing. Therefore, it is possible to select whether to read this voltage with the cursor key, to actually measure it from the waveform chart of the recording sheet with a ruler, or to input it to a personal computer for measurement.

The operation of the present invention configured as described above will be described below with reference to FIGS. In FIG. 1, when the power switch SW1 is turned on, the control power source,
At the same time when DC5V and DC6V are established, the timer reset circuit 4a resets the first timer 6 and the second timer 7. After turning on the detection start switch SW2,
From the time of opening, the first timer 1 (30 msec) operates and the trigger output section 17 triggers start. When the first timer 6 stops, the second timer 7 operates. In this case, the trigger from the trigger output unit 17 is continuously output. When the second timer 7 operates, the semiconductor relay (SSR) previously selected by the rotary switch is turned on. This rotary switch is 0A
SSR is not selected when (No load) is selected.

Although the SSR selection is not shown in detail, it is selected as follows by the diode matrix. [Current]: 0A → [SSR]: None, and so on, 10A
→ SSR1, 20A → SSR1 / 2 ・ 30A → SSR1 / 2 ・
3, 40A → SSR 1, 2, 3, 4. When the SSR is turned on, the selected dummy load of the dummy resistor section 16 is connected to AC voltage of 10, 20, 30,
40A current flows. When the second timer 7 stops, SS
R turns off and trigger stops.

The detected voltage waveform will be described based on the above operation. In FIG. 3, (a), (b),
(C) and (d) show voltage waveforms when load currents of 10, 20, 30, and 40 A are applied between the branch terminals to be detected, where the vertical axis represents voltage (V) and the horizontal axis represents Time (ms
ec), the part where the voltage waveform is decreasing indicates that the voltage drop at the time of load and therefore the voltage corresponding to the internal resistance is detected. For the voltage thus detected, the voltage drop is measured according to the ordinate scale, and the internal resistance is obtained from the corresponding load current.

The problem in accuracy of wiring resistance when using a dummy load will be described. The current value applied to the dummy load was fixed to 10, 20, 30, 40 A and actually measured. Since the dummy load is fixed, the current value also changes if there is a voltage drop in the wiring, so correction is necessary to improve the actual accuracy.

[0017]

As described above in detail, according to the invention described in claim 1, means for connecting between branch terminals of the low-voltage branch circuit to supply a predetermined load current, and one cycle for the connected low-voltage branch circuit. Of the load current, a detection means for detecting a voltage between the branch terminals corresponding to each load current, and a trigger output means for driving the detection means in conjunction with the operation of the timer. Since the internal resistance between the connection terminals is obtained based on this detection result, by detecting the voltage between the branch terminals with almost no influence on the low voltage branch circuit, the voltage drop, that is, The internal resistance can be obtained.

According to the second aspect of the present invention, the detecting means can obtain the voltage drop, that is, the internal resistance, by recording the voltage between the branch terminals.
The voltage between the branch terminals corresponding to each load current can be detected from the recording voltage, and the voltage drop, that is, the internal resistance can be obtained.

According to the third aspect of the invention, since the load current supply means is a semiconductor relay, it is possible to reliably supply a predetermined load current.

According to the invention described in claim 4, the timer comprises a first timer for setting a time for detecting the voltage before applying the load current, and a second timer for applying the load current for one cycle. Since it is a load device consisting of, it is possible to reliably detect the voltage in the unloaded state between the branch terminals and the voltage when a predetermined load current is applied, so that the voltage drop between the branch terminals and the internal resistance can be easily performed. Can be obtained.

[Brief description of drawings]

FIG. 1 is a block circuit diagram of an embodiment of a load device according to the present invention.

FIG. 2 is an output timing chart by timer output in one embodiment of the load device of the present invention.

FIG. 3 is a voltage waveform diagram of respective low voltage branch terminals for different load currents in the embodiment of the load device of the present invention.

[Explanation of symbols]

1 ... Control power supply SW1 ... Power switch 2, 3 ... Terminal 4 ... Timer circuit 4a ... Timer reset circuit SW2: Detection start switch 6 ... First timer 7 ... second timer 10 ... Semiconductor relay control unit 11, 12, 13, 14 ... Terminal 16: Dummy resistor part 17: Trigger output section 18 ... OR circuit 19 ... Detector

Claims (4)

[Claims] 1. A means for supplying a predetermined load current by connecting between branch terminals of a low-voltage branch circuit, a timer for flowing the load current for one cycle to the connected low-voltage branch circuit, and each load current. It has a detection means for detecting the voltage between the branch terminals and a trigger output means for driving the detection means in conjunction with the operation of the timer, and based on the detection result, the internal resistance between the connection terminals is set. A load device characterized by being obtained. 2. The load device according to claim 1, wherein the detection means is a recording device that records a voltage between the branch terminals corresponding to each of the load currents. 3. The load device according to claim 1, wherein the load current supply means is a semiconductor relay. 4. The timer comprises a first timer for setting a time for detecting a voltage before applying a load current and a second timer for applying the load current for one cycle. Item 1. The load device according to item 1 or 2.