JP3899280B2 - Overcurrent detection device - Google Patents

Description

[0001]
BACKGROUND 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 interrupts the circuit.
[0002]
[Prior art]
Conventionally, in order to prevent an overcurrent circuit breaker from being interrupted by an overcurrent and causing a power failure, an overcurrent that interrupts some loads connected to an alarm or circuit breaker when a preset threshold current is exceeded. There was a detection device.
[0003]
In such a device, a threshold value is set according to the current value at which the circuit breaker operates to break, and an alarm is issued when the current exceeds the threshold value, and the user either reduces a part of the load or causes the load circuit to A function to cut off a part of the circuit breaker was suppressed to prevent a power failure due to the circuit breaker breaking operation.
[0004]
The threshold value is simply a current value, or a combination of a current value threshold value and a threshold value for the duration of the current value is used to cut off an alarm or a part of the load.
[0005]
[Problems to be solved by the invention]
[0006]
However, there are many circuit breakers that use heat detection with bimetal for overcurrent detection and electromagnetic with oil coils as the buffer material. However, the circuit breaker functions as a function of current and time. Characteristics are more or less affected by ambient temperature. In other words, it operates at a lower current value when the ambient temperature becomes higher and operates 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. It is defined as.
[0007]
Therefore, in a conventional overcurrent detection device, the current value at which the circuit breaker does not operate within the assumed ambient temperature must be set as a threshold value, and at a lower ambient temperature, the circuit breaker is actually lower than at which it operates. There is a problem that electricity cannot be fully used because the alarm operation and the operation of cutting off some loads are performed with the current value. In general, in a bimetal circuit breaker, the operating current value changes by 5 to 20% per 10 ° C.
[0008]
Therefore, the present invention provides an overcurrent detection device that stops the use of an alarm or some load before the circuit breaker as described above , in particular, a circuit breaker, is operated regardless of the ambient temperature. The purpose is to stop the use of alarms and some loads immediately before the breaker actually breaks, so that the load connected to the circuit breaker can use as much electricity as possible.
[0009]
[Means for Solving the Problems]
.
[0010]
Therefore, in the first aspect of the present invention, it is used in combination with a circuit breaker for wiring in which the breaking operation current changes with a change in ambient temperature, provided with current detection means, and the detected current exceeds a preset threshold value. In an overcurrent detection device that shuts off an alarm or a part of the load circuit at the time, a temperature detection means for measuring the ambient temperature as needed and outputting the measured value as a voltage value, and a voltage from the temperature detection means A linear function I = f (T) {I is an operation setting current value, T that is approximated in advance with an actual measurement value of an operating current at which the circuit breaker actually performs a breaking operation at a predetermined ambient temperature. Comprises a threshold value setting means for obtaining the operation setting current value by substituting the voltage value corresponding to the ambient temperature into the ambient temperature} and determining the obtained result as the threshold value. Transition By at any time reflects the threshold to the threshold of the serial current is changed by the ambient temperature, at a current value where the circuit breaker is operated actually cut off, over-we characterized by interrupting the load circuit of the alarm or some A current detection device is provided.
[0011]
Delete [0012]
Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment of the present invention.
[0013]
Reference numeral 1 is an overcurrent circuit breaker which is a 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 2001 for detecting current is disposed. The current detection unit 2001 and the overcurrent detection device 2 are electrically connected, and the output of the current detection unit 2001 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.
[0014]
FIG. 2 is a block diagram showing the configuration of the overcurrent detection device 2. Reference numeral 2002 denotes temperature detection means, 2003 denotes threshold setting means, 2004 denotes determination means, 2005 denotes an alarm signal output means, and 2006 denotes an interruption signal output means.
[0015]
The temperature detecting means 2002 measures the ambient temperature and outputs the measured value as a voltage. In general, the relationship between the ambient temperature and the operating current value in an overcurrent circuit breaker 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 becomes higher and at a higher current value when the ambient temperature becomes lower.
[0016]
The threshold setting means 2003 sets the threshold so as to take into account the change in operating current due to the change in ambient temperature as described above. In this embodiment, the linear function I = f (T) {I is the operating set current value, T is ambient temperature}
Is used to approximate the measured value of the operating current of the overcurrent circuit breaker 1, and the operating current value at that temperature, that is, the threshold value is set at a certain temperature. The set threshold value is output to the determination unit 2004.
[0017]
The determination unit 2004 receives the outputs from the current detection unit 2001 and the threshold setting unit 2003, compares the load side current value obtained by the current detection unit 2001 with the threshold value obtained by the threshold setting unit 2003, and determines the load side. When the current value is larger than the threshold value, output is performed toward the alarm signal output means 2005 or the cutoff signal output 2006.
[0018]
Thus, since the overcurrent detection device 2 is configured to perform the output determination of the alarm signal or the cut-off signal while reflecting the change in the ambient temperature in the operation setting current value as needed, the overcurrent circuit breaker 1 in the change in the ambient temperature. Thus, the load device can be used up to the current value immediately before the overcurrent circuit breaker 1 operates efficiently at the ambient temperature at that time.
[0019]
Next, a second embodiment will be described in detail with reference to the drawings. FIG. 4 is a block diagram showing the configuration of the second embodiment of the overcurrent detection device 2 shown in FIG. Reference numeral 2001 denotes current detection means, 2002 denotes temperature detection means, 4001 denotes current duration measurement means, 4002 denotes determination means, 4003 denotes threshold setting means, 2005 denotes an alarm signal output means, and 2006 denotes an interruption signal output means.
[0020]
As described above, the temperature detection unit 2002 measures the ambient temperature and outputs the measured value as a voltage. In general, the relationship between the ambient temperature and the operating current value in an overcurrent circuit breaker 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 becomes higher and at a higher current value when the ambient temperature becomes lower.
[0021]
The threshold setting means 4003 sets a threshold so as to take into account changes in operating current due to changes in ambient temperature. In this embodiment, the linear function I = f (T) {I is the operating set current value, and T is the ambient temperature. }
Is used to approximate the measured value of the operating current of the overcurrent circuit breaker 1, and the operating current value at that temperature, that is, the threshold value is set at a certain temperature. The set threshold value is output to current duration measuring means 5001 and determination means 4002.
[0022]
The current duration measurement unit 4001 is connected to the current detection unit 2001, the threshold setting unit 5003, and the determination unit 4002. When the current value data obtained by the current detecting means 2001 and the threshold value obtained by the threshold setting means 4003, that is, the operating current value of the overcurrent circuit breaker 1 are compared, and the current value data exceeds the threshold value, The time over the time is measured, and time data is output to the determination unit 4002.
[0023]
The determination unit 4002 receives outputs from the current detection unit 2001, the threshold setting unit 4003, and the current duration measurement unit 4001 described above. The determination unit 4002 compares the load-side current value obtained by the current detection unit 2001 with the threshold value obtained by the threshold setting unit 2003, and the load-side current value is larger than the threshold value, and the current duration measurement unit 4001 When the time data output from the signal exceeds a predetermined time, the signal is output toward the alarm signal output means 2005 or the cutoff signal output 2006.
[0024]
In this way, the change in ambient temperature is reflected on the operation setting current value, that is, the threshold value as needed, and the duration of the current exceeding the threshold value is measured, and when a predetermined time is exceeded, an alarm signal or a cut-off signal is output. Since the overcurrent detection device 2 is configured to perform the determination, it is possible to absorb the change in the operating current value of the overcurrent circuit breaker 1 due to the change in the ambient temperature and to provide redundancy with respect to time. The load device can be used up to the current value immediately before the overcurrent circuit breaker 1 operates efficiently at the ambient temperature at that time.
[0025]
【The invention's effect】
As described above, according to the present invention, in the overcurrent detection device that stops the use of an alarm or a part of the load before the breaking operation of the circuit breaker for wiring whose breaking operation current changes with a change in ambient temperature . , so as to stop the use of the load alarm and some just before really breaking operation said circuit breaker regardless of the ambient temperature, the load connected to the circuit breaker for the interconnection using as many of the electrical It is possible to provide an overcurrent detection device that enables this.
[Brief description of the 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. FIG. 3 is a diagram showing a relationship between ambient temperature and operating current. A block diagram showing the configuration of a second embodiment of the overcurrent detection device 2 shown in FIG.
DESCRIPTION OF SYMBOLS 1 Overcurrent circuit breaker 2 Overcurrent detection apparatus 2001 Current detection means 2002 Current duration measurement means 2003 Threshold setting means 2004 Determination means 2005 Alarm signal output means 2006 Shutdown signal output means 4001 Current duration measurement means 4002 Determination means 4003 Threshold setting means

Claims (1)

Used in combination with a circuit breaker that changes the operating current according to changes in the ambient temperature, equipped with a current detection means, and an alarm or some load circuit when the detected current exceeds a preset threshold In the overcurrent detection device that cuts off the temperature, the ambient temperature is measured at any time and the measured value is output as a voltage value, the voltage value from the temperature detection means is input, and the wiring A linear function I = f (T) {I is an operation set current value, T is an ambient temperature}, which is approximated in advance with an actual measurement value of an operating current at which the circuit breaker actually performs a breaking operation at a predetermined ambient temperature. And a threshold value setting means for determining the operation setting current value by substituting the voltage value to determine the determined result as the threshold value, and reflecting the transition of the ambient temperature to the current threshold value as needed. The threshold By varying the of ambient temperature of, at a current value where the circuit breaker is operated actually cut off, an alarm or the overcurrent detecting apparatus characterized by blocking a part of the load circuit.

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