JP2014199726A - Undervoltage tripper for circuit breaker and overvoltage/undervoltage tripper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an undervoltage tripper capable of miniaturizing it and reducing costs, while stabilizing voltage sensitivity and ensuring delay-time characteristics.SOLUTION: An undervoltage tripper for a circuit breaker comprises: a low voltage detection part; a delay-time output part; a switch circuit interrupting an excitation magnetization current supplied to a coil based on an excitation magnetization interruption signals; and an interruption mechanism for interrupting power supply to a load apparatus based on the interruption of the excitation magnetization current for the coil. In the undervoltage tripper for the circuit breaker, the low voltage detection part 19 has a first comparator 21 for outputting a low voltage detection signal Vd by comparing a comparison voltage Vx changing based on a change of a commercial power supply voltage with a first threshold voltage Vt1, and the delay-time output part 20 has a counter 22 for performing a count-operation based on the input of the low voltage detection signal Vd and outputting a count value as a delay-time signal S1; and a count number comparator circuit 23 for outputting an excitation magnetization current interruption signal S2 by comparing the delay-time signal S1 with a preset threshold value.

Description

  The present invention relates to an undervoltage trip device used as an auxiliary device for a circuit breaker of a commercial power source.

  2. Description of the Related Art Conventionally, an undervoltage trip device for a circuit breaker operates to cut off power supply to a load device to which commercial power is supplied when the power voltage of the commercial power falls below a predetermined voltage.

  FIG. 12 shows a conventional example of an undervoltage trip device. The commercial power supply AC is full-wave rectified by the rectifier circuit 1, and an exciting current Ic based on the full-wave rectified voltage Vrec is supplied to the coil 3 wound around the fixed plunger 2. The commercial power supply AC is supplied to the rectifier circuit 1 via a sensitivity adjustment device 4 composed of a capacitor or a resistor, and a large-capacity capacitor is connected between both terminals of the coil 3 as a time delay setting device 5. .

  When the coil 3 is energized, the movable plunger 6 is attracted to the fixed plunger 2, and the movable plunger 6 is urged by a spring 7 in a direction away from the fixed plunger 2. Then, when the movable plunger 6 is pulled away from the fixed plunger 2 by the urging force of the spring 7, the shut-off device 8 is activated to cut off the supply of the power source VL to the load device.

  As shown in FIG. 13, in the undervoltage trip device configured as described above, when the commercial power supply AC is supplied at a substantially normal voltage and the exciting current Ic exceeding the threshold value It flows through the coil 3. The movable plunger 6 continues to be attracted to the fixed plunger 2 against the urging force of the spring 7. In this state, power is supplied to the load device.

  On the other hand, when the voltage of the commercial power supply AC decreases and the exciting current Ic falls below the threshold value It, the movable plunger 6 is pulled away from the fixed plunger 2 by the urging force of the spring 7, and as a result, the operation of the shut-off device 8 causes a load. The power supply to the device is cut off.

  The sensitivity adjusting device 4 is provided for adjusting the voltage of the commercial power supply AC that causes the movable plunger 6 to be separated from the fixed plunger 2. Further, the time delay setting device 5 operates the shut-off device 8 when the movable plunger 6 is separated from the fixed plunger 2 after a predetermined time td has elapsed with the excitation current Ic output from the rectifying circuit 1 being below the threshold value It. Thus, the operations of the movable plunger 6 and the shutoff device 8 are stabilized.

  Patent Documents 1 and 2 disclose a configuration similar to the undervoltage tripping device as described above. Patent Document 3 discloses an undervoltage trip device that allows an exciting current to flow through an exciting coil only when an abnormality occurs.

JP 2003-308775 A JP 2005-135690 A JP 61-124222 A

  In the undervoltage trip device as described above, the commercial power supply voltage when the movable plunger 6 is separated from the fixed plunger 2 depends on the magnetic characteristics of the fixed plunger 2 and the movable plunger 6, the shape of the attracting surface, and the like.

  For this reason, since the required precision is required for mechanical processing such as annealing of the magnetic body for forming the fixed plunger 2 and the movable plunger 6, polishing of the suction surface, and management of the gap of the suction surface, the processing cost is high. To rise.

  In addition, the operation of adjusting the sensitivity of the commercial power supply voltage with respect to the voltage change by the sensitivity adjustment device 4 is complicated, and in order to ensure sufficient time delay characteristics with the time delay setting device 5, a large capacity capacitor is required. Therefore, the size of the apparatus increases and the cost also increases.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an undervoltage trip device capable of reducing the size and reducing the cost while ensuring the stability of the voltage sensitivity and the time delay characteristic. There is to do.

  An undervoltage trip device that solves the above problems includes a low voltage detection unit that compares a commercial power supply voltage with a preset threshold voltage and outputs a low voltage detection signal, and the low voltage detection signal A time-delay output unit that outputs an excitation current cut-off signal when it continues for a set time, a switch circuit that cuts off the excitation current supplied to the coil based on the excitation current cut-off signal, and an excitation current to the coil In the circuit breaker undervoltage trip device having a shut-off mechanism for shutting off the power supply to the load device based on the shut-off of the low-voltage detector, the low-voltage detector is a comparison that changes based on a change in the commercial power supply voltage A comparator that compares the voltage with the threshold voltage and outputs the low voltage detection signal, and the delay output unit performs a counting operation based on the input of the low voltage detection signal, And a counter for outputting a Tokinobe signal, characterized in that a count number comparing circuit for outputting the excitation current cutoff signal is compared with the time extension signal with a preset threshold.

  In the above configuration, the low voltage detection unit outputs the low voltage detection signal for a preset time from when the comparison voltage falls below the threshold voltage regardless of the voltage level of the comparison voltage. It is preferable to do.

In the above configuration, it is preferable that the count number comparison circuit can adjust a threshold value based on an external control signal.
Further, in the above configuration, the low voltage detection unit calculates an effective value by integrating the commercial power supply voltage, and compares the effective value with the first threshold voltage as the comparison voltage. It is preferable to output a detection signal.

  Further, in the above configuration, the low voltage detection unit integrates the commercial power supply voltage to calculate an average value, and compares the average value with the first threshold voltage as the comparison voltage. It is preferable to output a detection signal.

In the above configuration, it is preferable that the switch circuit includes a transistor that is turned off based on the input of the excitation current cutoff signal to cut off the excitation current.
An overvoltage / undervoltage trip device that solves the above problem generates a low voltage detection signal by comparing a commercial power supply voltage with a preset first threshold voltage, and the low voltage detection signal Compared with the commercial power supply voltage and the preset third threshold voltage, the low voltage detector with a time delay setting that outputs the excitation current cutoff signal when it continues for a preset time or more. A detection signal is generated, and when the overvoltage detection signal continues for a preset time or longer, an overvoltage detection unit with a time delay setting that outputs an excitation current cutoff signal and a coil based on the excitation current cutoff signal are generated. Overvoltage / undervoltage tripping of circuit breakers with a switch circuit that cuts off the excitation current to be supplied and a cut-off mechanism that cuts off the power supply to the load equipment based on the interruption of the excitation current to the coil In the apparatus, the low voltage detection unit with time delay setting includes a low voltage detection unit and a time delay output unit, and the low voltage detection unit includes a comparison voltage that changes based on a change in commercial power supply voltage, A comparator that compares the threshold voltage with the low voltage detection signal and outputs the low voltage detection signal; the time delay output unit performs a count operation based on the input of the low voltage detection signal; And a count number comparison circuit that compares the time delay signal with a preset threshold value and outputs the excitation current cut-off signal.

  Further, in the above configuration, the first threshold voltage is set to a voltage higher than the comparison voltage when the cutoff mechanism stops operating due to a decrease in the excitation current, and the third threshold voltage is set. Is preferably set to a voltage lower than the comparison voltage when the overvoltage detector with time delay setting and the low voltage detector with time delay setting become inoperable.

  ADVANTAGE OF THE INVENTION According to this invention, size reduction and cost reduction can be aimed at, stabilizing the voltage sensitivity of an undervoltage trip device, and ensuring a time delay characteristic.

It is a block diagram which shows the undervoltage trip apparatus of one Embodiment. It is a circuit diagram which shows a low voltage detection part and a time delay output part. It is a timing waveform diagram which shows operation | movement of a low voltage detection part and a time delay output part. It is a circuit diagram which shows a switch circuit. It is a timing waveform diagram showing the operation of the second embodiment. It is a timing waveform diagram which shows operation | movement of 3rd embodiment. It is a block diagram which shows the overvoltage / undervoltage trip apparatus of 4th embodiment. It is a timing waveform diagram showing the operation of the overvoltage / undervoltage trip device. It is a circuit diagram which shows the overvoltage detection part with a time delay time setting. It is explanatory drawing which shows the setting of a threshold voltage. It is a circuit diagram which shows another example of a switch circuit. It is a circuit diagram which shows a prior art example. It is a timing waveform diagram which shows operation | movement of a prior art example.

(First embodiment)
Hereinafter, a first embodiment of an undervoltage trip device will be described with reference to FIGS.
In the undervoltage trip device shown in FIG. 1, the commercial power supply AC is full-wave rectified by the rectifier circuit 11, and the full-wave rectified voltage Vrec is output.

  The full-wave rectified voltage Vrec is supplied to one end of the coil 12 wound around the fixed plunger 14, and the other end of the coil 12 is connected to the switch circuit 13. Further, a capacitor C1 is connected in parallel between both terminals of the coil 12, and the exciting current Ic supplied to the coil 12 is slightly smoothed based on the full-wave rectified voltage Vrec.

  A movable plunger 15 that can be attracted based on the supply of the excitation current Ic is disposed in the vicinity of the fixed plunger 14, and the movable plunger 15 is urged by a spring 16 in a direction away from the fixed plunger 14. When the movable plunger 15 is pulled away from the fixed plunger 14 by the urging force of the spring 16, the shut-off device 17 is activated and the supply of power to the load device is shut off. The switch circuit 13, the fixed plunger 14, the movable plunger 15, and the shut-off device 17 constitute a shut-off mechanism.

  The full-wave rectified voltage Vrec is supplied to the power supply circuit 18, and the power supply circuit 18 generates a DC power supply voltage Vc based on the full-wave rectified voltage Vrec and supplies it to the low voltage detection unit 19 and the time delay output unit 20.

  As shown in FIG. 3, the low voltage detection unit 19 operates based on the supply of the DC power supply voltage Vc. When the full-wave rectified voltage Vrec becomes lower than the threshold voltage Vt1, the low voltage detection unit 19 outputs an H level low voltage detection signal Vd to the time delay output unit 20.

  The time delay output unit 20 generates a time delay signal S1 obtained by integrating the low voltage detection signal Vd. When the time delay signal S1 becomes higher than a preset threshold voltage Vt2, an excitation current cutoff signal is sent to the switch circuit 13. S2 is output. The excitation current cutoff signal S2 is a signal that switches from the H level to the L level when the delay signal S1 becomes higher than the threshold voltage Vt2.

  The switch circuit 13 operates to cut off the excitation current Ic based on the switching of the excitation current cut-off signal S2 from the H level to the L level. When the excitation current Ic is interrupted, the supply of the power source VL to the load device is interrupted by the interrupt mechanism.

  FIG. 4 shows an example of the switch circuit 13. The exciting current cut-off signal S2 is input to the base of the npn transistor Tr3 via the diode D, the collector of the transistor Tr3 is connected to the other end of the capacitor C1 and the coil 12, and the emitter is connected to the ground Vg. .

  Therefore, if the exciting current cut-off signal S2 is at the H level, the transistor Tr3 is turned on and the exciting current Ic is supplied to the coil 12. If the exciting current cut-off signal S2 becomes the L level, the transistor Tr3 is turned off and the exciting current Ic is turned on. Is cut off.

  Next, specific configurations of the low voltage detection unit 19 and the delay output unit 20 will be described with reference to FIG. In the low voltage detector 19, the full-wave rectified voltage Vrec is divided by resistors R1 and R2 connected in series with the ground Vg to generate a comparison voltage Vx, and the comparison voltage Vx and the threshold voltage are generated. The comparator 21 compares Vt1. When the comparison voltage Vx becomes lower than the threshold voltage Vt1, an H-level low voltage detection signal Vd is output from the comparator 21.

  The low voltage detection signal Vd output from the comparator 21 is input to the counter 22 of the time delay output unit 20. When the low voltage detection signal Vd is at the H level, the counter 22 performs a counting operation based on a preset clock signal and outputs the count value to the count number comparison circuit 23 as a time delay signal S1. Further, when the low voltage detection signal Vd becomes L level, the counter 22 resets the count value.

Therefore, when the low voltage detection signal Vd is maintained at the H level, the count value of the counter 22 increases, and the count value is output as the time delay signal S1.
In the count number comparison circuit 23, the input time delay signal S1 is compared with a count value set in advance as a threshold value N. When the count value of the time delay signal S1 is less than the threshold value, an excitation current cutoff signal S2 of H level is output to the switch circuit 13, and the count value of the time delay signal S1 is equal to or greater than the threshold value. In this case, an excitation current cutoff signal S2 of L level is output to the switch circuit 13.

The switch circuit 13 cuts off the connection between the other terminal of the coil 12 and the ground Vg on the basis of the L level excitation current cut-off signal S2 to cut off the excitation current Ic.
Next, the operation of the undervoltage tripping device configured as described above will be described with reference to FIG.

  When the commercial power supply AC is supplied at a normal voltage level, the peak value of the full-wave rectified voltage Vrec exceeds a preset threshold voltage Vt1, and thus the low voltage detection signal output from the low voltage detection unit 19 Vd becomes a pulse-like signal.

In this state, the time delay signal S1 output from the time delay output unit 20 is periodically reset, so that it is not counted up to the threshold value N.
Then, the exciting current cutoff signal S2 is maintained at the H level, and the exciting current Ic is continuously supplied to the coil 12 by the operation of the switch circuit 13. Therefore, the movable plunger 15 is maintained in the state of being attracted to the fixed plunger 14, and the shut-off device 17 does not operate.

  When the voltage of the commercial power supply AC decreases and the peak value of the full-wave rectified voltage Vrec falls below the threshold voltage Vt1, the low voltage detection signal Vd output from the low voltage detector 19 is maintained at the H level.

In this state, the time delay signal S1 output from the time delay output unit 20 is not reset, and thus is counted up to the threshold value N.
Then, the excitation current cut-off signal S2 output from the time delay output unit 20 becomes L level, and the excitation current Ic to the coil 12 is cut off by the operation of the switch circuit 13. As a result, the movable plunger 15 is separated from the fixed plunger 14, and the shut-off device 17 is activated to cut off the supply of the power source VL to the load device.

According to the present embodiment, the following effects can be obtained.
(1) When the voltage level of the commercial power supply AC drops below a predetermined level for a predetermined time or longer, the movable plunger 15 can be pulled away from the fixed plunger 14 to operate the shut-off device 17. Therefore, it is possible to prevent problems caused by operating the load device in a state where the voltage level of the commercial power supply AC is insufficient.
(2) The voltage sensitivity for detecting whether or not the voltage level of the commercial power supply AC is insufficient can be set by the threshold voltage Vt1 input to the comparator 21 by the low voltage detector 19. Therefore, stable voltage sensitivity can be easily set.
(3) The time delay from when the voltage level of the commercial power supply AC drops to an undervoltage until the excitation current cut-off signal S2 for cutting off the excitation current Ic is output from the counter 22 of the time delay output unit 20 The time delay signal S1 output as the count value can be generated by comparing the threshold value N with the count number comparison circuit 23. Accordingly, since the time delay can be set without using a large-capacitance capacitor, the undervoltage trip device can be reduced in size, the cost can be reduced, and the temperature characteristics can be improved. it can.
(Second embodiment)
FIG. 5 shows a second embodiment. In this embodiment, after the low voltage detection signal Vd once becomes H level, the low voltage detection signal Vd is not detected even during the predetermined time t1 even if the full-wave rectified voltage Vrec exceeds the threshold voltage Vt1. The low voltage detector 19 has a function of maintaining the voltage at the H level.

With such a configuration, the output level of the low voltage detection signal Vd can be stabilized even when high-frequency noise is present in the full-wave rectified voltage Vrec. Further, since it is not necessary to interpose a filter for removing high frequency noise in the input part of the low voltage detection part 19, the cost can be reduced.
(Third embodiment)
FIG. 6 shows a third embodiment. In this embodiment, the count number comparison circuit 23 has a function that makes it possible to adjust the count value that becomes the threshold value N based on an external control signal.

With such a configuration, it is possible to adjust the time from when the excitation low voltage detection signal Vd rises to the H level until the excitation current cutoff signal S2 falls to the L level.
(Fourth embodiment)
7 to 10 show a fourth embodiment. This embodiment is an overvoltage that cuts off the supply of the power supply voltage to the load device when the commercial power supply AC becomes an undervoltage similar to the first embodiment and when the commercial power supply AC becomes an overvoltage that is equal to or higher than a preset voltage. -Indicates an undervoltage trip device.

  In the overvoltage / undervoltage trip device shown in FIG. 7, a single-phase two-wire commercial power supply AC is supplied to the power supply circuit 32 and the voltage signal generator 33 via the switching circuit 31. The power supply circuit 32 generates a required DC power supply voltage Vc based on the supply of the commercial power supply AC, and supplies the DC power supply voltage Vc to the overvoltage detection unit 34 with time delay setting and the low voltage detection unit 35 with time delay setting. Supply.

  As shown in FIG. 8, the voltage signal generation unit 33 generates a full-wave rectified voltage Vrec obtained by full-wave rectification of the commercial power supply AC, and the overvoltage detection unit 34 with time delay setting and the low voltage detection with time delay setting. To the unit 35.

  The commercial power supply AC is supplied to one end of the coil 36, and the other end of the coil 36 is connected to the ground Vg via the switch circuit 37. If the switch circuit 37 is in a conducting state, the exciting current Ic is supplied to the coil 36.

  The coil 36 is wound around the fixed plunger as in the first embodiment, the movable plunger is attracted based on the supply of the excitation current Ic, and the movable plunger is pulled away from the fixed plunger based on the interruption of the excitation current Ic. The point that the shut-off device operates is the same as in the first embodiment.

  The low voltage detector 35 with time delay setting has the same configuration as the low voltage detector 19 and the time delay output unit 20 of the first embodiment shown in FIG. S2 is output.

  When the full-wave rectified voltage Vrec becomes lower than the threshold voltage Vt1, the time delay signal S1 rises. When the time delay signal S1 exceeds the threshold value N, the excitation current cutoff signal S2 becomes L level. As a result, the switch circuit 37 is turned off and the exciting current Ic is cut off.

  As shown in FIG. 9, the overvoltage detection unit 34 with time delay setting is composed of an overvoltage detection unit 38 and a time delay output unit 39. The overvoltage detection unit 38 is the low voltage detection unit 19 of the first embodiment except that the threshold voltage Vt3 is input to the negative side input terminal of the comparator 21 and the comparison voltage Vx is input to the positive side input terminal. It is the same composition as.

  In such an overvoltage detection unit 38, when the peak value of the full-wave rectified voltage Vrec becomes higher than the threshold voltage Vt3, the overvoltage detection signal Vd2 that the overvoltage detection signal Vd2 rises intermittently is output to the counter 22 of the delay output unit 39. To do.

  The time delay output unit 39 counter 22 performs a count operation every time the overvoltage detection signal Vd2 rises. Then, when the count value output as the delay signal S3 rises and exceeds the threshold value N, the excitation current cutoff signal S4 output from the count number comparison circuit 23 to the switch circuit 37 becomes L level. The supply of the excitation current Ic to the coil 36 is cut off.

When the exciting current Ic is interrupted, the power supply to the load device is interrupted by the operation of the interrupting mechanism, as in the first embodiment.
When the excitation current Ic is interrupted, the switching circuit 31 is rendered non-conductive due to a change in magnetic force generated by the coil 36, and the supply of the commercial power supply AC to the power supply circuit 32 and the voltage signal generator 33 is also interrupted.

  The excitation current cut-off signals S2 and S4 are output to the switch circuit 37 via an interface circuit, and the interface circuit has a function of supplying an L level input signal to the switch circuit 37 with priority.

  As shown in FIG. 10, in the overvoltage / undervoltage tripping device as described above, the threshold voltage Vt1 set by the low voltage detector 35 with time delay setting is reduced by the decrease in the excitation current Ic of the coil 36. The voltage is set higher than the voltage Vf1 input to the comparator 21 when the movable plunger cannot be attracted by the fixed plunger. At the same time, due to a drop in the supply voltage from the power supply circuit 32 due to a drop in the commercial power supply voltage, the overvoltage detection unit 34 with time delay setting and the low voltage detection unit 35 with time delay setting become voltages higher than the voltage Vf2 at which the operation becomes impossible. Is set.

According to the present embodiment, the following effects can be obtained.
(1) When the voltage level of the commercial power supply AC drops below a predetermined level for a predetermined time or more and rises above a predetermined level, the movable plunger can be separated from the fixed plunger to operate the shut-off mechanism. Therefore, it is possible to prevent problems caused by operating the load device when the voltage level of the commercial power supply AC is insufficient or operating the load device when the voltage level of the commercial power supply AC is overvoltage. Can do.
(2) Threshold voltage input to the comparator 21 by the low voltage detection unit 19 or the overvoltage detection unit 38 as a voltage sensitivity for detecting whether or not the voltage level of the commercial power supply AC is insufficient or overvoltage. It can be set by Vt1 and Vt3. Therefore, stable voltage sensitivity can be easily set.
(3) The time delay from when the voltage level of the commercial power supply AC drops to an undervoltage until the excitation current cut-off signal S2 for cutting off the excitation current Ic is output from the counter 22 of the time delay output unit 20 The time delay signal S1 output as the count value can be generated by comparing the threshold value N with the count number comparison circuit 23. Accordingly, since the time delay can be set without using a large-capacitance capacitor, the undervoltage trip device can be reduced in size, the cost can be reduced, and the temperature characteristics can be improved. it can. Even when the voltage level of the commercial power supply AC becomes an overvoltage, the excitation current cut-off signal S2 can be generated and output by the operation of the overvoltage detection unit 38.

In addition, you may change the said embodiment as follows.
The low voltage detector 19 of the first embodiment and the low voltage detector 35 with time delay setting of the second embodiment calculate the effective value by integrating the commercial power supply voltage, and the effective value and threshold value The voltages Vt1 and Vt3 may be compared.
The low voltage detector 19 of the first embodiment and the low voltage detector 35 with time delay setting of the second embodiment calculate the average value by integrating the commercial power supply voltage, and the average value and the threshold value Vt1 and Vt3 may be compared.
As shown in FIG. 11, in the switch circuits of the first and second embodiments, a pnp transistor Tr4 is used instead of the npn transistor, and the excitation current cutoff signal S4 is connected to the base of the transistor Tr4 via the inverter circuit 40. May be input. With such a configuration, when the exciting current cut-off signal S4 becomes H level and the exciting current Ic flows through the coil 12, the base voltage of the transistor Tr4 is almost at the ground Vg level. Therefore, even if the full-wave rectified voltage Vrec is reduced due to noise, the transistor Tr4 is maintained in the on state, and the exciting current Ic can be stably supplied to the coil 12.

  DESCRIPTION OF SYMBOLS 13 ... Switch circuit, 14 ... Shut-off mechanism (fixed plunger), 15 ... Shut-off mechanism (movable plunger), 17 ... Shut-off mechanism (shut-off device), 19 ... Low voltage detection part, 20 ... Time delay output part, 21 ... First 22 ... counter, 23 ... count number comparison circuit, AC ... commercial power supply, Vt1 ... first threshold voltage, Vt2 ... second threshold voltage, Vt3 ... third threshold voltage, Vd: Low voltage detection signal, Ic: Excitation current, S1: Time delay signal, S2: Excitation current cutoff signal, Vx: Comparison voltage.

Claims (8)

A low-voltage detection unit that compares a commercial power supply voltage with a preset threshold voltage and outputs a low-voltage detection signal;
When the low voltage detection signal continues for a preset time or longer, a time delay output unit that outputs an excitation current cutoff signal;
A switch circuit that cuts off the excitation current supplied to the coil based on the excitation current cut-off signal;
In an undervoltage trip device for a circuit breaker provided with a shut-off mechanism for shutting off power supply to a load device based on shut-off of an exciting current to the coil
The low voltage detection unit includes a comparator that compares the threshold voltage with a comparison voltage that changes based on a change in commercial power supply voltage, and outputs the low voltage detection signal.
The time delay output unit is
A counter that performs a counting operation based on the input of the low voltage detection signal and outputs the count value as a time delay signal;
An undervoltage trip device for a circuit breaker, comprising: a count number comparison circuit that compares the time delay signal with a preset threshold value and outputs the excitation current interruption signal. In the circuit breaker undervoltage trip device according to claim 1,
The low voltage detection unit outputs the low voltage detection signal for a preset time from when the comparison voltage falls below the threshold voltage regardless of a voltage level of the comparison voltage. Undervoltage trip device for circuit breakers. In the circuit breaker undervoltage trip device according to claim 1 or 2,
An undervoltage tripping device for a circuit breaker, wherein the count number comparison circuit is capable of adjusting a threshold value based on an external control signal. In the circuit breaker undervoltage trip device according to any one of claims 1 to 3,
The low voltage detection unit integrates the commercial power supply voltage to calculate an effective value, compares the effective value with the first threshold voltage as the comparison voltage, and outputs the low voltage detection signal. A circuit breaker undervoltage trip device characterized by the above. In the circuit breaker undervoltage trip device according to any one of claims 1 to 3,
The low voltage detecting unit integrates the commercial power supply voltage to calculate an average value, compares the average value with the first threshold voltage as the comparison voltage, and outputs the low voltage detection signal. A circuit breaker undervoltage trip device characterized by the above. In the circuit breaker undervoltage trip device according to any one of claims 1 to 5,
2. The circuit breaker undervoltage trip device according to claim 1, wherein the switch circuit includes a transistor that is turned off based on an input of the excitation current cutoff signal to cut off the excitation current. A commercial power supply voltage and a preset first threshold voltage are compared to generate a low voltage detection signal, and when the low voltage detection signal continues for a preset time or more, an excitation current cutoff signal Low voltage detector with time delay setting
The commercial power supply voltage is compared with a preset third threshold voltage to generate an overvoltage detection signal, and when the overvoltage detection signal continues for a preset time, an excitation current cutoff signal is output An overvoltage detector with a time delay setting,
A switch circuit that cuts off the excitation current supplied to the coil based on the excitation current cut-off signal;
In an overvoltage / undervoltage trip device for a circuit breaker provided with a shut-off mechanism for shutting off power supply to a load device based on shut-off of an excitation current to the coil,
The low voltage detection unit with time delay setting includes a low voltage detection unit and a time delay output unit,
The low voltage detection unit includes a comparator that compares the threshold voltage with a comparison voltage that changes based on a change in commercial power supply voltage, and outputs the low voltage detection signal.
The time delay output unit is
A counter that performs a counting operation based on the input of the low voltage detection signal and outputs the count value as a time delay signal;
An overvoltage / undervoltage tripping device for a circuit breaker comprising: a count number comparison circuit for comparing the time delay signal with a preset threshold value and outputting the excitation current interruption signal. In the overvoltage / undervoltage trip device for a circuit breaker according to claim 7,
The first threshold voltage is set to a voltage higher than the comparison voltage when the cutoff mechanism stops operating due to a decrease in the excitation current, and the third threshold voltage is set with a time delay time setting. An overvoltage / undervoltage tripping device for a circuit breaker, wherein the overvoltage detection unit and the low voltage detection unit with time delay setting are set to a voltage lower than the comparison voltage when the operation becomes impossible.