JP2003299241A - Overcurrent detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To use as much electricity as possible for loads connected to a circuit breaker by stopping the use of an alarm or some of the loads immediately before really turning off a circuit breaker regardless of ambient temperatures, in an overcurrent detection device for stopping the use of the alarm or some of the loads before turning off the circuit breaker. <P>SOLUTION: This overcurrent detection device is used in a combination with an overcurrent circuit breaker for detecting an overload and cutting off a circuit, includes a current detection means to turn off the alarm or some of load circuits when the detected current exceeds a preset threshold value, and comprises a means for changing the threshold value with the ambient temperature. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overcurrent detection device used in combination with an overcurrent circuit breaker that detects an overload and shuts off the circuit.

[0002]

2. Description of the Related Art Conventionally, in order to prevent an overcurrent circuit breaker from performing an interruption operation due to an overcurrent and causing a power failure, an alarm or a part of a load connected to the circuit breaker is interrupted when a preset threshold current is exceeded. There was such an overcurrent detection device.

In such a device, a threshold value is set according to the current value at which the circuit breaker operates to interrupt the circuit, and when the current exceeds the threshold value, an alarm is issued and the user either reduces a part of the load or the device A function to cut off a part of the load circuit is provided to suppress the current to prevent a power failure due to the breaking operation of the circuit breaker.

Some of the thresholds are simply current values, and some of the alarms and some of the loads are cut off by combining the thresholds of the current value and the thresholds of the duration of the current value.

[0005]

[Problems to be Solved by the Invention]

However, the circuit breakers are mainly of the heat detection type using a bimetal for overcurrent detection and the electromagnetic type using an electromagnetic coil with oil as a buffer material.
The breaking action characteristics as a function of the current and the time are greatly affected by the ambient temperature. That is, it operates at a lower current value when the ambient temperature becomes higher, and at a higher current value when the ambient temperature becomes lower. Therefore, the rated current value of the circuit breaker is the current value that operates within the reference time at the reference ambient temperature. Has been defined as.

Therefore, in the conventional overcurrent detection device, the current value at which the circuit breaker does not operate within the assumed ambient temperature must be set as the threshold value, and the circuit breaker actually operates at a lower ambient temperature. There is a problem that electricity cannot be fully used because the alarm operation and the interruption of some loads are performed at a lower current value. Generally, in a bimetal type circuit breaker, the operating current value changes by 5 to 20% per 10 ° C.

Therefore, the invention of the present application is an overcurrent detecting device for stopping the use of an alarm or a part of the load before the breaking operation of the circuit breaker as described above, regardless of the ambient temperature. The purpose is to stop the alarm and use of some loads immediately before the actual disconnection operation so that the load connected to the circuit breaker can use as much electricity as possible.

[0009]

[Means for solving the problems].

Therefore, in the invention of claim 1, it is used in combination with an overcurrent circuit breaker which detects an overload and shuts off the circuit, and is provided with a current detection means, and the detected current has a preset threshold value. An overcurrent detecting device for shutting off an alarm or a part of a load circuit when the threshold value is exceeded is provided with a means for changing the threshold according to an ambient temperature.

According to the second aspect of the present invention, it is used in combination with an overcurrent circuit breaker which detects an overload and shuts off the circuit. The current detection means is provided, and the detected current has a preset current threshold value. An overcurrent detection device for shutting off an alarm or a part of load circuits when the current duration threshold value is exceeded, wherein the threshold value has means for changing the ambient temperature. Is provided.

DETAILED DESCRIPTION OF THE INVENTION.

The present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing the first embodiment of the present invention.

Reference numeral 1 is an overcurrent circuit breaker, 2 is an overcurrent detection device, and 2001 is a current detection means. On the load side of the overcurrent circuit breaker 1, current detection means 20 for detecting current is provided.
01 is provided. The current detection means 2001 and the overcurrent detection device 2 are electrically connected, and the current detection means 200
The output of 1 is input to the overcurrent detection device 2. In this embodiment, a current transformer is used as the current detection means 2001, and the current value on the load side of the overcurrent circuit breaker 1 is output as a voltage signal.

FIG. 2 is a block diagram showing the configuration of the overcurrent detection device 2. Reference numeral 2002 is a temperature detecting means, 2003 is a threshold value setting means, 2004 is a judging means, 2005 is an alarm signal output means, and 2006 is a cutoff signal output means.

The temperature detecting means 2002 measures the ambient temperature and outputs the measured value as a voltage. Generally, regarding the relationship between the ambient temperature and the operating current value in an overcurrent circuit breaker, the operating current value also changes as the ambient temperature changes, as shown in the graph of FIG. That is, the overcurrent circuit breaker 2 operates at a lower current value when the ambient temperature is higher, and at a higher current value when the ambient temperature is lower.

The threshold value setting means 2003 sets a threshold value so as to consider the change of the operating current due to the transition of the ambient temperature as described above, and in this embodiment, the linear function I = f (T) {I is the operation setting. The current value, T is the ambient temperature} and is approximated to the actual measured value of the operating current of the overcurrent circuit breaker 1 to set the operating current value at that temperature at a certain temperature, that is, the threshold value. The set threshold value is the determination means 20.
It is output to 04.

The judging means 2004 receives the outputs from the current detecting means 2001 and the threshold setting means 2003, and compares the load side current value obtained by the current detecting means 2001 with the threshold obtained by the threshold setting means 2003. If the current value on the load side is larger than the threshold value, the alarm signal output means 2005
Alternatively, the output is performed toward the cutoff signal output 2006.

Since the overcurrent detection device 2 is configured so as to judge the output of the alarm signal or the cutoff signal while reflecting the transition of the ambient temperature in the operation set current value as described above,
It is possible to absorb changes in the operating current value of the overcurrent circuit breaker 1 due to changes in ambient temperature, and use load equipment up to the current value immediately before the overcurrent circuit breaker 1 operates efficiently at ambient temperature at that time. can do.

Next, the second embodiment will be described in detail with reference to the drawings. FIG. 4 shows the overcurrent detection device 2 shown in FIG.
6 is a block diagram showing a configuration showing a second exemplary embodiment of FIG.
Reference numeral 2001 is a current detecting means, 2002 is a temperature detecting means, 4
001 is a current duration measuring means, 4002 is a judging means, 4003 is a threshold setting means, 2005 is an alarm signal output means, and 2006 is a cutoff signal output means.

As described above, the temperature detecting means 2002 measures the ambient temperature and outputs the measured value as a voltage. In general, regarding the relationship between the ambient temperature and the operating current value in an overcurrent circuit breaker, the operating current value also changes as the ambient temperature changes, as shown in the graph of FIG. That is, the overcurrent circuit breaker 2 operates at a lower current value when the ambient temperature is higher, and at a higher current value when the ambient temperature is lower.

The threshold value setting means 4003 sets a threshold value so as to take into consideration the change of the operating current due to the transition of the ambient temperature. In this embodiment, the linear function I = f (T) {I is the operation setting current value, T Is approximated to the actually measured value of the operating current of the overcurrent circuit breaker 1 by using the ambient temperature}, and the operating current value at that time at a certain temperature, that is, the threshold value is set. The set threshold value is output to the current duration measuring means 5001 and the determining means 4002.

The current duration measuring means 4001 comprises a current detecting means 2001, a threshold setting means 5003 and a judging means 40.
02 is connected. The current value data obtained by the current detection unit 2001 and the threshold value obtained by the threshold value setting unit 4003, that is, the operating current value of the overcurrent circuit breaker 1 are compared, and when the current value data exceeds the threshold value, The time during which the time is exceeded is measured, and time data is output to the determination unit 4002.

The judging means 4002 receives outputs from the above-mentioned current detecting means 2001, threshold setting means 4003 and current duration measuring means 4001. Determination means 4002
Compares the current value on the load side obtained by the current detection means 2001 with the threshold value obtained by the threshold value setting means 2003, the current value on the load side is larger than the threshold value, and is output from the current duration measuring means 4001. If the time data exceeds a predetermined time, the alarm signal output means 200
5 or the cutoff signal output 2006.

In this way, the transition of the ambient temperature is reflected in the operation set current value, that is, the threshold value at any time, and the duration of the current exceeding the threshold value is measured, and an alarm signal or interruption is given when the predetermined time is exceeded. Since the overcurrent detection device 2 is configured to determine the output of the signal, it is possible to absorb the change in the operating current value of the overcurrent circuit breaker 1 due to the transition of the ambient temperature, and to provide the redundancy with respect to time. Therefore, the load device can be efficiently used up to the current value immediately before the overcurrent circuit breaker 1 operates at the ambient temperature at that time.

[0025]

As described above, according to the present invention, in the overcurrent detection device for stopping the alarm and the use of a part of the load before the breaking operation of the circuit breaker, the circuit breaker regardless of the ambient temperature. To provide an overcurrent circuit breaker that stops the use of alarms and some loads immediately before the circuit breaks so that the load connected to the circuit breaker can use as much electricity as possible. You can

[Brief description of drawings]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 4]

[Explanation of symbols]

1 Overcurrent circuit breaker 2 Overcurrent detection device 2001 Current detection means 2002 Current duration measuring means 2003 threshold setting means 2004 Judgment means 2005 alarm signal output means 2006 Cutoff signal output means 4001 Current duration measuring means 4002 determination means 4003 threshold setting means

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[Procedure amendment]

[Submission date] April 18, 2002 (2002.4.1)
8)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of an overcurrent detection device 2.

FIG. 3 is a diagram showing the relationship between ambient temperature and operating current.

FIG. 4 is a block diagram showing a configuration showing a second embodiment of the overcurrent detection device 2 shown in FIG.

[Explanation of symbols] 1 Overcurrent circuit breaker 2 Overcurrent detection device 2001 Current detection means 2002 Current duration measuring means 2003 threshold setting means 2004 Judgment means 2005 alarm signal output means 2006 Cutoff signal output means 4001 Current duration measuring means 4002 determination means 4003 threshold setting means

Claims (2)

[Claims] 1. A current detecting means, which is used in combination with an overcurrent circuit breaker for detecting an overload and breaking the circuit,
In an overcurrent detection device that shuts off an alarm or some load circuits when the detected current exceeds a preset threshold value, the threshold value has means for changing the ambient temperature. Current detection device. 2. Used in combination with an overcurrent circuit breaker that detects an overload and shuts off the circuit, and comprises current detection means,
In an overcurrent detection device which shuts off an alarm or some load circuits when the detected current exceeds a preset current threshold value and current duration threshold value, the threshold value is changed by the ambient temperature. An overcurrent detection device having: