JPS6315616A - Circuit breaker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a so-called electronic circuit breaker that detects overcurrent due to overload or short circuit using an electronic circuit, and particularly relates to a so-called electronic circuit breaker that detects overcurrent due to overload or short circuit using an electronic circuit. The present invention relates to an electronic circuit breaker having a display function suitable for notifying the outside of the passage of time.

[Conventional technology]

For conventional electronic circuit breakers, Japanese Patent Application Laid-Open No. 59-20901
As described in No. 7, when an overload occurs, there is a device that changes the blinking cycle of the light emitting display element depending on the magnitude of the current to notify the magnitude of the overfa A, but it is difficult to shut off from the occurrence of an overload. No consideration was given to informing the user of the elapsed time.

[Problem that the invention seeks to solve]

However, in order to check the tripping characteristics of electronic circuit breakers, there are cases where it is necessary to know the tripping time when an overload occurs without interrupting the load current. It is necessary to know how much time has elapsed and then estimate how much time is left to shut off.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an electronic circuit breaker in which the magnitude of overcurrent and the elapsed time from occurrence of overload to interruption can be determined by the blinking state of a light-emitting display element, and the interruption time can be predicted. It's about doing.

[Means for solving problems]

The above purpose is during the electronic circuit to detect overcurrent.

A time delay pulse generation circuit generates repeated pulses with a cycle corresponding to the magnitude of the detected overcurrent, and the output pulses of the time delay pulse generation circuit are counted, and when a predetermined count value is reached, the magnetic attraction is activated. A time delay counter circuit that outputs a signal to operate the removal device; and a blinking cycle switching device that decodes output signals of a plurality of different cycles of the time delay counter circuit and generates blinking cycle switching signals sequentially shifted in time. lU road and =
A blinking display pulse generation circuit that generates repetitive pulses with a constant cycle, a blinking display counter circuit that counts the output pulses of the blinking display pulse generation circuit, and a plurality of output signals of different cycles from the blinking display counter circuit. and a light-emitting display blinking circuit that sequentially time-divides the light-emitting display element using the time-divided signal and blinking the light-emitting display element, so that the blinking cycle of the light-emitting display element becomes shorter as time elapses from the occurrence of overload. This is achieved by configuring it as follows.

[Effect]

When an overload occurs, the cycle of the repetitive pulses generated from the time delay pulse generation circuit becomes shorter as the magnitude of the overcurrent increases, and accordingly, the time delay counter circuit counts faster and the cutoff operation time becomes shorter. Become. (Generally, the trip characteristics are set so that an overcurrent of 125% of the rated current causes a cutoff operation in about 10 minutes, and an overcurrent of 1000% of the rated current causes a cutoff operation in about 10 seconds.) Therefore, for example, a time delay counter circuit The outputs taken from the (n-1) stage and (++-2) stage of the 0 stage counter are decoded by the blinking cycle switching circuit to create a 4-stage blinking cycle switching signal, and this blinking cycle switching signal is used for the blinking display. When output signals of four different periods from the counter circuit are sequentially time-divided and the time-divided signals are used to blink the light-emitting display elements, the blinking cycles of the two light-emitting display elements are as shown in FIG.

t2, t3. It changes in four stages like t4, and the time interval T between the changes becomes shorter as the magnitude of the overcurrent becomes larger.

In this case, it is known that the cut-off time is approximately 4XT, so by visually measuring the flashing cycle of the light-emitting display element and the time interval of its change, it is possible to know the time elapsed from the occurrence of the overload to the cut-off. It is possible to predict the cut-off time before the cut-off occurs.

Furthermore, the magnitude of the overcurrent can also be estimated from the time interval of changes in the blinking cycle.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

The third part is an overall configuration diagram of an embodiment of an electronic circuit breaker according to the present invention, with Mig side terminals 1. Load side terminal 2, main circuit conductive section 3, main circuit opening/closing mechanism section 4. It consists of a current detecting current transformer 5 installed at each pole, an overcurrent detecting electronic circuit 6, and a magnetic trip device @7.

The schematic configuration of the overcurrent detection electronic circuit 6 in this embodiment is shown in FIG. 4. The current detection current transformer 5 shown in FIG. It is input to the input terminal 8 of the detection electronic circuit 6. The maximum current detection circuit 9 in the overcurrent detection electronic circuit 6 rectifies the secondary current of the current transformer 5, extracts the maximum current from each pole ta current, and converts it into a voltage in the overcurrent determination circuit 1O. Converts the long time circuit 11 according to its voltage level. Short time circuit 12. One of the instantaneous circuits 13 is operated. During the long time, the magnetic trip device 7 shown in FIG. 3 is excited from the constant output terminal 15, and the opening/closing mechanism 4 is operated to cut off the overcurrent. Reference numeral 16 denotes a test terminal, and by passing a test current through this test terminal 16, an overload state or a short circuit state can be generated in a simulated manner, and the trip characteristics can be checked. Reference numeral 17 denotes a display circuit which is the main part of the present invention, and is composed of a blinking cycle switching circuit 20 operated by the output of the long time limit circuit 11, a pulse generation circuit 211 for 1 blink display, a counter circuit 22 for blinking display, and a light emission display blinking circuit 23. has been done.

FIG. 1 is a detailed diagram of the long time limit circuit 11 and display circuit 17. In FIG. 1, VBB, VCC.

VDD is a DC power supply voltage created by converting the output of the maximum current detection circuit 9 into a voltage, and Vl is proportional to the magnitude of the overcurrent created by converting the output of the maximum current detection circuit 9 into a voltage. input voltage, EO.

EC is an operation signal output from the overcurrent determination circuit 10, G is a ground terminal, and R1-R21 are resistors.

C1 to C4 are capacitors, Dl is a light emitting display element, Ul,
tJ2, U3. tJ6. U7 is an operational amplifier, of which Ul constitutes an integrator together with capacitor C1, and the others are used as comparators. U4 and C8 are binary counters, U5 is a decoder, U9 is a power transistor; It is a transistor.

When an overload condition is detected in the overcurrent determination circuit 10,
The signal EO applied to the output side C point of the operational amplifier 01 via the resistor R3 changes from the rL level to the I4 level, and the signal EC applied to the reset terminals (R) of the binary counters U4 and C8 changes to the rHJ level. to rLJ level, whereby the long time limit circuit 11 and display circuit 17 become operable. In the initial state it is 1
The outputs of the comparators U2 and U3 of the delay pulse generation circuit 18 are at the rHJ level, so the operational amplifier Ul
The capacitor C1 is charged with the difference between the input voltage v1 applied to the non-inverting input terminal a and the constant voltage applied to the inverting input terminal a, and the integrator output voltage v4 increases. Once the threshold is reached.

The outputs of comparators U2 and U3 become "L" level, and as a result, the charge of capacitor C1 is discharged through resistor r<1, and the output of comparator 1:2 is connected to the non-inverting input terminal through resistor 1. To be returned to d.

When the L'2 output reaches the rLJ level, the oscillation output from the connection point f between the non-inverting input terminal d and resistors R4 and R5 also reaches rL.
Then, when the potential of the inverting input terminal e of the comparator U2 falls to the rLJ level due to the discharge of the capacitor C1, the outputs of the comparators U2 and U3 become "H" again.
level and return to the initial state. Along with this, the connection point f
By repeating 6 or more operations, the oscillation output from the oscillation output also becomes "H" level.

The oscillation output from the connection point f becomes a repetitive pulse wave.

The period of this pulse wave is determined by the charging period of the capacitor C1, and the larger the input voltage Vl is, the shorter the period of the pulse wave is. and enter
will be counted. When the count reaches the set value,
A signal is outputted from the output terminal goggle Qn of the final stage to the tree circuit 14, and the magnetic sample removing device 7 is operated. As a result of the above, the time delay characteristic of [long time delay circuit] 1 is obtained. In this embodiment, the binary counter t:11 (n
-1) Stage output terminal Qn-1 and (1-2) stage output terminal Q The time rL from the output terminal YO1Y1.Y2.Y3 of U5 to the signal level of inputs A and B sequentially.
Output the blinking cycle switching signal that reaches the J level.

When the signal reaches r1=) level, the current flowing into these output terminals causes the LEDt of the light emitting part of the photocoupler to
Jlo, Ull, Ul2. Ul3 sequentially emits light, and the corresponding phototransistors U20, U21 . U2
2. Turn on U23 for that time. On the other hand, capacitor C3 and comparator IJ6 charged with DC power supply voltage VBB
．． U7. A blinking display pulse generation circuit 21 consisting of resistors R14 to R20 (C3, U6, and U7 are each C
], corresponding to U2, U3) generates a repetitive pulse of a constant period and the 1 blink display counter circuit 22 is bypassed! 1 counter and 8's tarok end 1 (<("I')/\ large input, pipelicer link 8, this pulse is output from the output terminal of each stage of karate L, Q20, Q21, Q23) This output is Q20.Q21, Q22.Q2
3, which is a signal whose period becomes progressively shorter. This 020. Q2
1.Q22. A phototransistor U20. U2]
, t, 722°U23, and the power transistor U of the light emitting display blinking circuit 23 is time-divided by this time-divided signal.
9 is pulse-driven to blink the light emitting display element D1.

The change in the signal level of each terminal is as shown in FIG. 2. The output of the decoder U5 determines the time interval T at which the blinking cycle changes, and the output of the binary counter U8 determines the blinking cycle t'1. t2t3. t4 is determined.

As a result, the blinking period of the light-emitting display element D1 changes in four stages as time elapses from the occurrence of the overload, as shown in the figure, and the period gradually becomes shorter.

Here, the 1-blink display pulse generation circuit 21 operates with a constant DC power supply voltage VBII, VLlr).

The cycle of the repetitive pulses hexagonally applied to the CP terminal of binary counter L:8 is constant regardless of the magnitude of the overcurrent, so the blinking cycle from t1 to t4 does not change, and only the time interval T between changes of one blinking cycle is over. It varies depending on the magnitude of the current.

What is the number of stages of change in the blinking cycle?

It can be arbitrarily selected depending on the input/output ratio of the decoder U5.

〔Effect of the invention〕

According to the present invention, the light-emitting display element blinks when an overload occurs, and the blinking cycle becomes stepwise shorter as time passes, so the magnitude of the overcurrent and the occurrence of the overload can be determined from one blinking cycle and the time interval of its change. It is possible to know the elapsed time from 1 to 3 and to predict the 8 to 8 shutdown time. Therefore, by stopping the test current to the test terminal before operation of the magnetic trip device, it is possible to check the trip characteristics during overload without interrupting the load current, making it easier to maintain and inspect the circuit breaker. I can do something.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a main part showing an embodiment of the present invention, Fig. 2 is a timing chart thereof, Fig. 3 is an overall configuration diagram of an embodiment of a circuit breaker according to the present invention, and Fig. 4 is its timing chart. FIG. 29 is a diagram of an electronic circuit for overcurrent detection. 6: Electronic circuit for overcurrent detection, 7: Magnetic trip device, 1
8: Time delay pulse generation circuit, 19: Time delay counter circuit, 20: Flashing cycle switching circuit, 21: Pulse generation circuit for flashing display, 22: Counter circuit for flashing display, 23: Light emitting display flashing circuit, Dl: Light-emitting display element 1/' ≦ Figure 3

Claims (1)

[Claims] 1. In a circuit breaker having an electronic circuit that detects overcurrent and a magnetic trip device that converts an electric signal from the electronic circuit into a mechanical trip operation, the electronic circuit includes:
A time delay pulse generation circuit generates repeated pulses with a cycle corresponding to the magnitude of the detected overcurrent, and the output pulses of the time delay pulse generation circuit are counted, and when a predetermined count value is reached, the magnetic attraction is activated. A time delay counter circuit that outputs a signal to operate the removal device; and a blinking cycle switching device that combines the output signals of a plurality of different cycles of the time delay counter circuit and generates sequentially time-shifted blinking cycle switching signals. a circuit, a pulse generation circuit for blinking display that generates repetitive pulses of a constant cycle, a counter circuit for blinking display that counts output pulses of the pulse generation circuit for blinking display, and a plurality of different cycles of the counter circuit for blinking display. a light-emitting display blinking circuit that sequentially time-divides the output signal of the light-emitting display element using the above-mentioned blinking cycle switching signal and blinks the light-emitting display element using the time-divided signal, and the blinking cycle of the light-emitting display element changes as time elapses from the occurrence of overload. A circuit breaker characterized by having a short period of time.