JPH027827A - Delay type earth-leakage breaker - Google Patents

Abstract

PURPOSE:To reduce the number of parts and to obtain an inexpensive breaker by sharing, the circuitry except the control circuit of a delay type earth-leakage breaker with a high speed type earth-leakage breaker and integrating the common circuitry. CONSTITUTION:Earth-leakage detection circuit 12, output circuit 8 and comparison/delay circuit 4 are integrated IC 15 and power is fed from a constant voltage circuit 14. Upon detection of earth leakage, the earth leakage detection circuit 12 in the integrated high speed earth-leakage breaker produces a signal for turning the output circuit 8 ON when the voltage across a capacitor C1 reaches to the threshold voltage of a one-shot circuit 7. When a control circuit 13 comprising transistors Q1, Q2 which are turned ON when the voltage across the capacitor C1 reaches to the base-emitter voltage and resistors R1, R2 for dividing the source voltage smoothed upon turning ON of the transistor Q2 and feeding the divided voltage to the comparator 9 in the comparison/delay circuit 4 is additionally provided in the IC 15, a delay type earth-leakage breaker is constituted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a delay type earth leakage breaker that disconnects the power supply when an earth leakage is continuously detected for a predetermined period of time.

[Conventional technology 1 More than 99% of earth leakage breakers are high-speed types.
There are very few delay type earth leakage breakers. Figure 6 shows a high-speed earth leakage breaker. In this high-speed earth leakage breaker, the output of the zero-phase current transformer ZCT for detecting leakage current is amplified by the amplification/comparison circuit section 1, and the intermittent output generated when the amplified output is higher than a predetermined voltage is used to connect the capacitor C6. When the capacitor C8 is charged and the voltage across the capacitor C8 exceeds a predetermined voltage,
S connected in series to the excitation coil of the earth leakage breaker body
CRQ is turned on in the comparison output circuit section 2, and excitation current is caused to flow through the excitation coil to open the switching contact r. Power for each of the above parts is supplied from a power supply circuit 3. Note that the circuit consisting of the amplification/comparison circuit section 1 and the comparison output circuit section 2 is implemented as an IC. Conventionally, a delay type earth leakage breaker has been constructed by adding a comparison delay circuit section 4 externally to this high speed type earth leakage breaker as shown in FIG. Since the added comparison delay circuit section 4 is constructed using another IC or a discrete circuit, a large number of parts and alpha losses are required.

Therefore, there is a problem that the size of the delay type earth leakage breaker becomes large and the cost becomes high. Therefore, it may be possible to reduce the number of parts by integrating the comparison delay circuit section 4 with the circuit section 1.2 to reduce the number of components.As mentioned above, this delay type earth leakage breaker is produced in extremely small quantities. However, there was a problem in that there was no economy of scale, and converting to IC would actually increase costs.

[Problem to be Solved by the Invention 1] The present invention has been made in view of the above-mentioned points, and its purpose is to reduce the number of parts by using an IC, and to provide an inexpensive delayed type earth leakage. Our goal is to provide breakers.

[Means for Solving the Problems 1] In order to achieve the above object, the present invention provides an earth leakage detection circuit unit that detects an earth leakage by detecting that the output of a zero-phase current transformer becomes equal to or higher than a predetermined voltage; An output circuit that is driven by the detection output of the detection circuit unit turns on the switching element and sends excitation current to the excitation coil of the earth leakage breaker body, and detects that the input voltage has exceeded a predetermined voltage. A comparison delay circuit section that generates an output when the above state continues for a predetermined period of time or more, and a comparison delay circuit section that blocks the input of the output of the earth leakage detection circuit section to the output circuit, and a comparison delay circuit section that generates an output when the above condition continues for a predetermined period of time or more. The control circuit includes a control circuit that inputs a signal of a predetermined voltage or higher to the circuit section.

(Function) As described above, the present invention is driven by an earth leakage detection circuit unit that detects an earth leakage by detecting that the output of a zero-phase current transformer exceeds a predetermined voltage, and a detection output of this earth leakage detection circuit unit. By providing an output circuit that turns on the PIJ switching element and flows excitation current to the excitation coil of the earth leakage breaker body, this circuit can detect earth leakage of the high-speed earth leakage breaker, and also when the input voltage is higher than a predetermined voltage. By providing a comparison delay circuit unit that detects whether the input voltage has reached a predetermined voltage or higher and generates an output when the state where the input voltage is equal to or higher than a predetermined voltage continues for a predetermined time or more, the comparison delay circuit unit is equipped with a single-phase 3#
By inputting the voltage of the neutral wire of the i-type power supply line, this comparison delay circuit section can be used as an open phase detection circuit for detecting an open phase of the neutral wire. By providing a control circuit that blocks input to the output circuit of the earth leakage circuit and inputs a signal of a predetermined voltage or higher to the comparison delay circuit when an output from the earth leakage detection circuit occurs, it is possible to create a delay type earth leakage breaker using the entire circuit. This allows you to configure the . In other words, the circuits of the delay type earth leakage breaker except the control circuit can be shared with the high speed type earth leakage breaker, and the common circuit part can be integrated into an IC, reducing the number of parts. By being able to share the same information, economies of scale can be achieved and costs can be reduced.

(Example) An embodiment of the present invention is shown in FIGS. 1 to 5.

In this example, if the circuit of the delayed edge earth leakage breaker can be shared with the high-speed type earth leakage breaker, economies of scale will be obtained and the circuit can be integrated into an IC. The delay circuit section 4 is used as an open phase detection circuit for detecting an open phase in the neutral wire of a high-speed earth leakage breaker for a single-phase three-wire power line.

The delay type earth leakage breaker of this embodiment includes an earth leakage detection circuit section 12 for a high speed type earth leakage breaker, and this earth leakage detection circuit ff1S.
The output circuit 8 is driven by the detection output of 12 and turns on 5CRQ to send an excitation current to the excitation coil of the earth leakage breaker body. The comparison delay circuit section 4 generates an output when the above state continues for a predetermined period of time or more. The earth leakage detection circuit section 12 includes an amplifier 5 that amplifies the output of a zero-phase current transformer ZCT that detects leakage current, a comparator 6 that compares the output of the amplifier 5 with a reference voltage, and a comparator 6 that amplifies the output of the amplifier 5. The capacitor C3 is charged with the output when the voltage is higher than the reference voltage of the capacitor C3, and the one-shot circuit 7 generates an output when the voltage across the capacitor C0 exceeds a predetermined voltage. Note that the output circuit 8 is driven by the output of the one-shot circuit 7, and at this time turns on 5CRQ. Also, J
The seven comparison delay circuits 4 include a humpator 9 that compares the input voltage with a reference voltage, a capacitor C2 that is normally in a charging state and is discharged when the input voltage is higher than the reference voltage, and a waveform shaping of the voltage across the capacitor C2. A waveform shaping circuit 10 and a capacitor C that is charged when the voltage across the capacitor C2 is equal to or lower than the threshold voltage of the waveform shaping circuit 10.
1 and a delay circuit 11 that turns on the output circuit 8 when the voltage across the capacitor C3 reaches a predetermined voltage. Note that the circuits within the frame of the one-dot chain line of the earth leakage detection circuit section 12, the output circuit 8, and the comparison delay circuit 4 are integrated into an IC. Further, power to each circuit of the ICl 3 is supplied from a constant voltage circuit 14.

FIG. 3 shows a circuit diagram of a high-speed earth leakage breaker manufactured using the above ICI 5. First, the earth leakage detection operation of this high-speed earth leakage breaker will be explained. Leakage current is zero phase current transformer 2'
, C'F occurs on the primary side, a leakage signal voltage ■L appears on the secondary side. This leakage signal voltage ■1 is shown in Fig. 4 (a
), the signal is amplified by the amplifier 5. Note that the output of this amplifier 5 is an output that swings in both positive and negative directions with reference to the bias voltage VB. During the half cycle in which the output of the amplifier 5 is negative, the reference voltage V of the comparator 6
The capacitor C1 is charged during the period when the voltage is below r.

Note that when the leakage current is small, the output V of the amplifier 5,
The reference voltage V of comparator 6 during the half cycle in which V is negative
The period during which the voltage becomes less than rl is short, and therefore, as shown on the left side of FIG. 4(b), the voltage Vcl across the capacitor C1 does not reach the threshold voltage Vcl that turns on the circuit 7. At this time, at the same time as the charging of the capacitor C1 ends, the charge in the capacitor CI is discharged with a current larger than the charging current. In addition, when the leakage current is large, the period when the output vL of the amplifier 5 is less than the reference voltage Vr of the comparator 6 during a negative half cycle is less than the reference voltage Vr of the comparator 6. Therefore, as shown on the right side of FIG. The voltage Vcl across C1 is set by the funshot circuit 7 #S1
The threshold voltage of V reaches the third voltage. Therefore, at this time, the output circuit 8 is turned on by the output of the one-shot circuit 7, and the output Vo at the noise level shown in FIG. 4(C) is output. Note that in this case, the capacitor C1 is discharged with a small current. When the voltage Vc1 across the capacitor C1 drops to a second threshold voltage V□11° lower than the first threshold voltage VTH of the one-shot circuit 7, the output ■0 of the output circuit 8 becomes a low level.

In other words, when the period L2 in FIG. 4(e) is open, the output Vo of the output circuit 8 is at a high level, and this output
RQ is turned on to cut off the power supply.

In this high-speed leakage breaker, the leakage current when the period during which the amplitude of the output V1 of the amplifier 5 is equal to or higher than the reference voltage Vr1 of the comparator 6 coincides with the line 2 in FIG. 4 is an exciting current.

When the above comparison delay circuit 4 is used as an open phase detection circuit for the neutral wire N of a single-phase three-wire high-speed earth leakage breaker for Input the voltage ■N into the comparator 9.

This voltage vH normally has a waveform with uniform amplitude as shown on the left side of FIG. 5(,). Now, if neutral #i1N is disconnected, power source 4112. Depending on the load condition, the voltage (1)8 has a waveform whose amplitude alternately increases and decreases as shown on the right side of FIG. 5(a). Therefore, when the neutral #iN is disconnected, the amplitude of the voltage vN becomes the reference voltage Vr of the comparator 9.
The value of the voltage dividing resistor is adjusted so that the voltage is 2 or more. Therefore, when a disconnection of the neutral wire N occurs, a period occurs in which the amplitude of the voltage 8 becomes equal to or higher than the reference voltage Vr2 of the comparator 9, and the capacitor C2, which is in a charged state, is intermittently discharged during this period. Note that this capacitor C2 is designed to be charged when the discharging period ends, as shown in FIG. fpJ5 (b).

The voltage Vc2 across this capacitor C2 is the waveform shaping circuit 1
0 threshold voltage VTH3 or less, the fifth
As shown in Figure (c), charging of the capacitor C3 is started. When the voltage Vc across the capacitor C1 reaches the threshold voltage 7 of the delay circuit 11, the output circuit 8 is driven by the output of the delay circuit 11, and the output Vo
becomes high level, and the power is cut off in the same way as in the case of electric leakage.

By the way, as shown in FIG. 5(a), there are cases where the single shot/is NP is superimposed on the neutral #IN, and this single shot/is NP portion becomes higher than the reference voltage Vr2 of the comparator 9. In this case, Before the voltage Vc3 across the capacitor C5 reaches the threshold voltage 7e of the delay circuit 11, the voltage c2 across the capacitor C2 becomes equal to or higher than the threshold voltage VTH1 of the waveform shaping circuit 10, and the capacitor C1
Since charging is stopped and corrected, malfunctions due to single-shot/is NP do not occur.

In ICl3, if a leakage is detected as described above,
The earth leakage detection circuit section 12 of the high-speed earth leakage breaker immediately outputs a signal that turns on the output circuit 8. The condition for outputting the signal that turns on the output circuit 8 in this manner is when the voltage Ve across the capacitor C1 reaches the threshold voltage VTH (approximately 1.8 V) of the one-limit circuit 7.

Therefore, if the voltage Vcl across the capacitor C1 is clamped below the threshold voltage Vd, the output circuit 8
will no longer turn on. Furthermore, since it is known that there is a current leakage because the nh'/IL voltage Vc1 across the capacitor C1 rises, the comparison delay circuit section 4 is activated when the voltage Vcl across the capacitor C1 rises to a predetermined voltage. For example, it can be a delay type earth leakage breaker. Therefore, in this embodiment, a transistor Q is turned on when the voltage across the capacitor C1 reaches the base-emitter voltage.
A transistor Q2, which turns on once when this transistor is turned on, is connected in series with this transistor Q2,
A control circuit 13 consisting of resistors R, R2 which divides the power supply voltage obtained by rectifying and smoothing the power supply voltage and inputs it to the comparator 9 of the comparison and delay circuit section 4 when the transistor Q2 is turned on is added to the ICl3 to prevent delay type earth leakage. This constitutes a breaker.

As shown in FIG. 2(, ), when a leakage current is detected in the zero-phase current transformer ZCT, the capacitor C3 is charged in the same manner as described above. When used as a delayed earth leakage 7' breaker, the base and emitter of the transistor Q1 are connected to both ends of the capacitor C5, so the voltage vcl across the capacitor c1 is equal to the voltage between the base and emitter of the transistor Q1. It is clamped to 0.6V, and the output of the one-shot circuit 7 does not occur. The voltage Vcl across the capacitor CI at this time is shown in the same figure (b).

In this way, when the voltage Vc1 across the capacitor CI becomes the base-emitter voltage of the transistor Q1, the transistor Q1 is turned on. Therefore, the transistor Q2 is also turned on, and the power supply voltage obtained by rectifying and smoothing the power supply voltage is transferred to the resistors R,,R
The voltage divided by 2 is input to the humpator 9. This input voltage is shown in FIG. 2(c). Here, if the power supply voltage obtained by rectifying and smoothing the power supply voltage is Vs, the peak value of the input voltage VI is 2,=--L-Xvs R, +R2. Since this input voltage (■1) exceeds the reference voltage Vr2 of the humpator 9, when this input voltage (■1) is applied manually, as shown in FIG. Capacitor c2 is intermittently discharged.

Therefore, as shown in FIG. 2(e), the charged state of the capacitor C3 is maintained, and after a predetermined time, the output circuit 8 is turned on by the output of the delay circuit 11 (FIG. 2(f)), and 5CRQo is turned on to turn on the power supply line. It operates as a delay type earth leakage breaker that shuts off Q7. In this way, according to this embodiment, the above-mentioned ICI
5 can be shared, which reduces the number of parts. Moreover, since the high-speed earth leakage breaker and the rc15 described above can be used in common, economies of scale can be achieved and the cost can be reduced.

[Effect of the Invention 1] As described above, the present invention includes an earth leakage detection circuit section that detects that the output of a zero-phase current transformer exceeds a predetermined voltage and detects an earth leakage, and a detection output of this earth leakage detection circuit section. This circuit is equipped with an output circuit that turns on the switching element and sends an excitation current to the excitation coil of the earth leakage breaker body, so this circuit can detect earth leakage in the high-speed earth leakage breaker, and also when the input voltage is higher than a specified voltage. It is equipped with a comparison delay circuit that detects whether the input voltage has reached a predetermined voltage or higher and outputs an output when the input voltage remains at a predetermined voltage or higher for a predetermined time or more. By inputting the voltage of the neutral line of the line, this comparison delay circuit can be used as an open phase detection circuit to detect open phase of the neutral line, and the output of the earth leakage detection circuit is input to the output circuit. Since it is equipped with a control circuit that manually inputs a signal of a predetermined voltage or higher to the comparison delay circuit section when the output of the earth leakage detection circuit section occurs, a delay type earth leakage breaker can be constructed using the entire circuit. In other words, the circuits of the delay type earth leakage breaker except for the control circuit can be shared with the high speed type earth leakage breaker. Therefore, the common circuit section can be made into an IC and the number of parts can be reduced, and the above IC can also be used in common with the high speed type earth leakage breaker. This has the effect of producing economies of scale and making it cheaper.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of an embodiment of the present invention, Figure IItJ2 is an explanatory diagram of the same operation as above, and Figure 3 is a circuit diagram of a high-speed earth leakage breaker manufactured using the same IC as above. Figure 5 is an explanatory diagram of the same operation as above, Figure 6 is a circuit diagram of a high-speed type earth leakage breaker, and Figure 7 is a circuit diagram of a conventional delay type earth leakage breaker. 4 is a comparison delay circuit section, 8 is an output circuit, 12 is an earth leakage detection circuit section, 13 is a control circuit, 7. CT is a zero phase current transformer. Agent Patent Attorney Ishi 1) 艮 776图'r! , 7a

Claims (1)

[Claims] (1) An earth leakage detection circuit that detects earth leakage by detecting that the output of the zero-phase current transformer exceeds a predetermined voltage, and a earth leakage breaker that turns on a switching element driven by the detection output of this earth leakage detection circuit. An output circuit that flows excitation current to the excitation coil of the main body, and a comparison delay circuit that detects when the input voltage exceeds a predetermined voltage and generates an output when the input voltage remains at the predetermined voltage or higher for a predetermined period of time or more. and a control circuit that prevents the output of the earth leakage detection circuit from being input to the output circuit and inputs a signal of a predetermined voltage or higher to the comparison delay circuit when the output of the earth leakage detection circuit occurs. A delay type earth leakage breaker characterized by: