JPH03169220A - Open-phase breaker - Google Patents

Abstract

PURPOSE:To prevent an accident due to open-phase, from being generated in a state that a detection wire is missed to be connected to an electric circuit, by discharging electricity from a first capacitor when the charged voltage of the first capacitor is higher than the voltage of the detection wire, and by charging a second capacitor, to trip a main circuit contact. CONSTITUTION:The charged voltage of a capacitor 22 is compared with the voltage of a detection wire 4 or a resistor 21. Then, in a state that the detection wire 4 is not connected to an electric circuit 25' and the charged voltage of the capacitor 22 is higher, the charged voltage of the capacitor 22 is forcibly discharged, and a waveform shaping circuit 15 is operated, and a delay circuit 16 is driven, and a capacitor 23 is charged, and to the gate of a thyristor 11, the trigger voltage of voltage Vout is applied, and by a tripping coil 3, a main circuit contact 2 is contrived to be tripped.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is directed to an open-phase circuit breaker that detects abnormal voltage due to an open phase in a single-phase three-wire electrical circuit and interrupts the electrical circuit. The present invention relates to a technology for preventing an accident from occurring due to an open phase cutoff function not operating when an open phase occurs in an electrical circuit because the open phase detection line is not connected to the electrical circuit.

[Conventional technology]

Conventionally, an open-phase circuit breaker having a circuit configuration shown in FIG. 5 has been used.

That is, for the open phase breaker 1, 24, 25, and 26 are single-phase three-wire electric circuits of Ll, N, and L2 on the power supply side, respectively, and 24', 25', and 26' are L1 and L2 on the load side, respectively.
This is the N and L2 electrical circuit. The electric circuits on each power supply side and load side are connected by main circuit contacts 2.

50 is a rectifier diode 5,
6, 7. This detector is rectified by a voltage trotub resistor l7 and is supplied with power via a smoothing capacitor 18.The detector has a function to detect leakage through a path consisting of a one-shot circuit and an output circuit, and a waveform shaping circuit. ，
It also has the function of detecting abnormal voltage through a delay circuit and an output circuit.

Since the issue here is the abnormal voltage detection function, only the operation thereof will be explained below using the diagram. Reference numeral 4 denotes a neutral open-phase detection line exposed outside the open-phase circuit breaker 1, which is connected to the N-pole circuit 25' on the load side of the open-phase circuit breaker 1. Detection line 4
is connected to the ground line via a plurality of voltage dividing resistors 20 and 21.

A resistor 20.21 is connected across the resistor 210 connected in this manner, with the voltage between Ll and N and the voltage between L2 and N being half-wave rectified and combined to give an appearance of full-wave rectification.
A voltage Vibl divided by is generated as shown in FIG. Vibl is input to a comparator 14 and compared with Vsl, and when Vibl exceeds Vsl, an output is generated to a waveform shaping circuit 15. The waveform shaping circuit 15 normally charges the capacitor 22 to the vwf voltage, but the comparator 1
When the output from the capacitor 4 is received, the voltage of the capacitor 22 is immediately discharged, and when the voltage becomes lower than VW, the delay circuit 16 is driven to start charging the capacitor 23 to Vtd. When the charging voltage of the capacitor 23 reaches a certain value vtd, the delay circuit 1
6 drives the output circuit and applies V to the gate of the thyristor 11.
OUT voltage is applied to turn on the tripping coil 3.
The main circuit contact 2 is tripped by applying current to the main circuit to disconnect the power supply side and load side electrical circuits. In the above operation, Vsl is set higher than Vib1 in which the voltages between Ll-N and L2-N are evenly applied, so that no output is generated from the comparator 14, for example. If the connection of the N-pole circuit is broken in the circuit on the power supply side from the connection point of the detection line 4, resulting in an open phase state, Ll-N, L2 on the load side will be affected due to the unbalance of the load input.
The voltage between N becomes unbalanced, and V1 old exceeds <Vsl as shown in the right half of FIG. Once Vh1 is V
When it exceeds sl, the charging voltage ■wf of the capacitor 22 is discharged to OV, and the capacitor 23 starts charging like Vtd, but even if Vibl falls below Vsl and the capacitor 22 starts charging again like Vwf, Vwf
Before reaching Vw, V1 old again exceeds Vsl, at which point Vwf is discharged to OV again, and this repeats from then on, and Vwf is not charged until it finally reaches Vw.
During this time, the capacitor 23 continues to be charged to Vtd, and finally reaches Vtd, and the delay circuit drives the output circuit, which applies the voltage of Vout to the gate of the thyristor 11.

Note that 13 is a constant current circuit that supplies a current determined by the value of the resistor 19 to the capacitor 22 and the capacitor 23.

[Problems with conventional techniques and techniques]

In the above, if the detection line 4 is not connected to the N pole,
Since the voltage of Vibl is not generated across the resistor 210 and the open phase detection function of the open phase circuit breaker 1 does not work, when voltage is applied to the load in this state, the neutral line (N pole ) is disconnected and an open phase occurs, between Ll and N on the load side,
There is a problem in that the voltage between L2 and N causes an unexpected imbalance due to the impedance distribution of the load, causing the load to burn out. In addition, the above-mentioned detection line is connected to the electric circuit 25' outside the circuit breaker 1.
Separate connection to the circuit breaker was not necessary for conventional circuit breakers that did not have an open phase protection function, so it became an extra work when installing the circuit breaker, and it was often forgotten because it added to the work burden. .

[Means to solve the problem]

In view of the above problems, the present invention provides power supply to the load side by automatically tripping the main circuit contact 2 of the circuit breaker 1 and making it impossible to turn on the circuit breaker 1 when the detection line 4 is not connected to the electric circuit 25'. To prevent forgetting to connect the detection line 4, the present invention compares the charging voltage terminal of the capacitor 22 with the voltage of the detection line 4 or the resistor 21, and connects the detection line 4. is not connected to the electric line 25' and the charging voltage terminal of the capacitor 22 has a higher voltage,
A discharging means for forcibly discharging the charging voltage of the capacitor 22 is provided, the waveform shaping circuit 15 is activated to drive the delay circuit 16, the capacitor 23 is charged, and a trigger voltage of V out is applied to the gate of the thyristor 11. , the main circuit contact 2 is tripped.

〔Example〕

FIG. 1 shows a first embodiment of the present invention. The difference from the conventional circuit in FIG. 5 is that the diode 32.
33, an extra transistor 31 is included. The transistor 31 is a PNP transistor, and has the charging voltage side of the capacitor 22 as its emitter and the earth line side as its collector, and its base and the detection line 4 are connected by a diode 32 with the base side as the anode side.

The detection line 4 and the ground line are connected by a k diode 33 with the detection line 4 side serving as a cathode.

The operations of the diode 32 and the transistor 31 will be described. When the capacitor 22 is being charged, the voltage of the detection line 4 changes from the charging voltage to the on-voltage between the anode and cathode of the diode 32 (approximately 0.7V) and the transistor 3l.
When the voltage becomes less than the sum of the emitter and pace-on voltage (approximately 0.6V), the voltage between the diode '32 and the emitter and base of the transistor 31 turns on, and the transistor 3
The emitter and collector of the capacitor 1 are also electrically connected to discharge the charging voltage of the capacitor 22. Note that the diode 33 is for protecting the transistor 31 when a reverse voltage is applied to the detection line 4. In the above-mentioned open-phase circuit breaker, if the detection line 4 is securely connected to the electric line 25', when the electric line is in a normal state with no open phase, the voltage V ibl shown in FIG. 2 will be present across the resistor 21. is occurring. V1 old is Ll-N
Since there is a balance between L2-N and L2-N, the comparator 140 does not reach the reference value Vsl, and the circuit breaker 1 does not operate. Also Vi
When bl becomes lower than Vo', which is the voltage obtained by subtracting the on-voltage of the diode 32 and the base-emitter on-voltage of the transistor 310 from the charging voltage of the capacitor 22, converted into the voltage across the resistor 210, the capacitor 22 charges the transistor 31. The charging voltage of the capacitor 22 becomes the voltage V at which the waveform shaping circuit 15 drives the delay circuit 16.
w or less, the delay circuit 9-16 charges the capacitor 23 to Vtd, but V
Since ibl immediately recovers to a voltage higher than the aforementioned Vo', the charging voltage Vνf of the capacitor 22 also immediately recovers to a voltage higher than Vw, and the charging of the capacitor 23 is also stopped and discharged when Vwf recovers to Vw. Vtd is the delay circuit 16
does not reach the voltage vtd that drives the output circuit, and the circuit breaker 1 does not operate.

Next, when an unbalance occurs in the voltages between Ll-N and L2-N, the voltage of one of the phases exceeds Vs1 in the V1 old model of FIG.
is discharged, Vwf falls below Vw, and delay circuit 1
6 starts charging the capacitor 23.

When Vi old falls below Vsl, the capacitor 22 becomes V again.
Vwf starts to be charged like wf, but when Vtbl falls below the above-mentioned Vo', Vwf that starts to be charged is discharged by the transistor 31, and this process is repeated from now on. Since Vwf cannot reach Vw, the capacitor 23 is charged. is performed continuously, and the charging voltage Vtd eventually reaches Vtd, the delay circuit 16 drives the output circuit, generates Vout, and the thyristor 1l is turned on. Pull out contact 2.

As described above, as long as the detection line 4 is securely connected to the electric line 25', the circuit breaker operates in the same manner as the conventional open phase circuit breaker shown in FIG.

On the other hand, if the detection line 4 is not connected to the electric path 25', as shown in FIG. When the potential becomes much lower than the charging potential of the capacitor 22, the transistor 31 is turned on and the charging voltage Vwf of the capacitor 22 is discharged, so that Vwf never reaches Vw. Therefore, the fourth
As shown in the figure, from the moment power is supplied, the capacitor 23 is at Vt.
Charging starts as shown in d, and eventually reaches vtd, and the voltage Vout is applied to the gate of the thyristor 11 to turn it on, and the tripping coil 3 trips the main circuit contact 2.

After main circuit contact 2 is tripped, manually reset main circuit contact 2 again.
Even if the voltage is turned on, it is difficult to keep the main circuit contact turned on unless the detection line 4 is connected to the electric circuit 25' by repeating the above operation. Although the comparing means and the discharging means are constituted by one PNP transistor, for example, the voltage comparing means and the discharging means may be constituted separately and connected by something like a photocoupler. Furthermore, the same effect can be obtained even if a slight discharging resistor is inserted between the charging voltage terminal of the transistor 31 and the capacitor 22, or between the transistor 31 and the ground line.

Next, FIG. 7 shows a second embodiment of the present invention.

In FIG. 7, 34 is a diode, 35 is a resistor, and 3
4 and 35 are connected in series between the connection point of the voltage dividing resistor 20 and 21 and the charging voltage terminal of the first capacitor 22, and the diode 34 connects the charging voltage terminal of the first capacitor 22 to the anode. There is as a side. In the above, the voltage comparing means is the diode 34, and the discharging means is the diode 4.
and resistor 35 and resistor 21.

In the first embodiment shown in FIG. 1, the voltage comparison means was connected to the charging voltage terminal of the capacitor 22 and the ends of the four detection lines of the resistor 20, but in this example, the charging voltage of the capacitor 12 and between the contact points of resistors 20 and 21. This means that in a 100/200V single-phase three-wire circuit, the voltage between the detection line 4 and the ground line of the detector is approximately 140cm at its peak when there is no open phase, and the series combined resistance of resistors 20 and 21 is set to about several hundred kΩ to reduce current consumption, and when connected to the end of the detection line 4 side of the resistor 20 and the charging voltage end of the capacitor 22, the capacitor 22
It is said that the discharge current cannot be obtained sufficiently. Since the reference voltage for comparison of the comparator 14 is approximately 3V, the resistor 21 is selected to have a resistance of several kilohms, and if the resistance is of this value, the capacitor 22 can be sufficiently discharged. Reference numeral 35 represents a resistor for appropriately adjusting the discharge time, and it may or may not be provided.

In the second embodiment shown in FIG. 7, the operation is such that when the voltage between the connection point of the resistor 21 and the resistor 20 and the ground line becomes lower than the charging voltage of the capacitor 22, the charging voltage of the capacitor 22 is connected to the diode 34. , resistance 35, resistance 21
2 and 3 of the circuit of FIG. 1.
In the circuit shown in FIG. 1, the peak voltage of the detection line 4 is 140V, whereas the constant charging voltage at the charging voltage end of the capacitor 22 is about 1.
Since it is 4V, it is a very low level, and when the detection line 4 is connected to the electric path 25', the time for Vibl to fall below Vo' and discharge the capacitor 22 is set to be very short. , In the circuit shown in Fig. 7, the constant charging voltage at the charging voltage terminal of the capacitor 22 is about 1.4 V compared to the old peak value of Vi, which is 3 V. The operation is almost the same as that of the circuit shown in FIG. 1, except that the time for discharging the capacitor 22 is longer.

〔effect〕

As described above, in the present invention, the detection wire or A voltage comparison means is provided between the connection point of the voltage dividing resistors and the charging voltage terminal of the first capacitor which is always in a charging state, so that the voltage on the detection line side is -14- lower than the charging voltage of the first capacitor. When the charging voltage of the first capacitor decreases, the discharging means connected between the charging voltage terminal of the first capacitor and the ground line operates to cause the charging voltage of the first capacitor to drop below the first threshold value. At both ends, the voltages between L1 and N and L:2 and N are each half-wave rectified in a different manner so that a combined voltage is generated, and the voltage between L1 and N and L2 and N is When either one exceeds the reference value, the first capacitor that had been in a charged state until then is discharged, and the second capacitor detects that the charging voltage of the first capacitor has fallen below the first threshold value. When the charging voltage of the second capacitor reaches a second threshold, an output voltage is generated, and the output voltage triggers the thyristor to energize the tripping coil and close the main circuit contacts. In an open-phase circuit breaker configured to trip, when the detection line is not connected to the N pole outside the circuit breaker and no voltage is generated across the voltage dividing resistor, the detection line is detected from the charging voltage of the first capacitor. Since the line voltage is lower, the first capacitor is discharged, and the second capacitor is energized, causing the tripping coil to trip the -15- main circuit contact, so the breaker supplies the load ζ voltage. In addition, according to the present invention, the emitter of the PNP transistor is connected to the charging voltage terminal of the first capacitor, and the collector is connected to the earth line. Connect the base to the detection line through a diode with the pace side as the anode, or connect between the resistance point of the voltage dividing resistors 20 and 21 and the charging voltage end of the capacitor 22 with a diode with the capacitor 22 side as the anode. Therefore, it is possible to construct the voltage comparing means and the discharging means with a very simple circuit.

[Brief explanation of the drawing]

Fig. 1: Circuit configuration diagram of an open-phase circuit breaker according to the first embodiment of the present invention. Fig. 2: The detection line is connected to the N-pole circuit and an open-phase occurs at the N-pole. The operation time chart of the open-phase circuit breaker shown in Figure 1 when there is no open phase circuit breaker. 16- Operation time chart of the phase breaker, Figure 3... Operation time chart of the open phase breaker shown in Figure 1 when the detection line is not connected to the N-pole circuit, Figure 5... Circuit configuration diagram of the conventional open phase breaker, Fig. 6... Operation time chart of the open phase breaker in Fig. 5, Fig. 7... Circuit diagram of the open phase breaker according to the second embodiment. Circuit configuration diagram, 1...Open phase breaker, 2...Main circuit contact, 3...Tripping coil, 4...Detection line, 5, 6, 7. 8... Rectifier diode,
1l... Thyristor, 14... Comparator, 15... Waveform shaping circuit, 16... Delay circuit, 20.21... Voltage dividing resistor, 22... First -17 3...Second capacitor, 1...PNP transistor, 2...Diode, 4...Diode, O...Detector.

Claims (3)

[Claims] (1) Connect the detection line to the N pole of the single-phase 3-wire electric line outside the circuit breaker, and connect it to the ground line of the detector via multiple voltage dividing resistors connected in series inside the circuit breaker. L on both ends of the resistor
The voltages between the 1 and N poles and between the L2 and N poles are each half-wave rectified in a different manner so that a combined voltage is generated.
When either the voltage between the 1-N pole or between the L2-N pole exceeds the reference value, the first capacitor that had been in a charging state until then is discharged, and the charging voltage of the first capacitor becomes the first capacitor. When it detects that the voltage has dropped below the threshold, it charges the second capacitor, and when the charging voltage of the second capacitor reaches the second threshold, it generates an output voltage, and the output voltage drives the thyristor. In an open phase breaker that is triggered to energize the tripping coil and trip the main circuit contact, a voltage comparison is made between the detection line or the connection point between the voltage dividing resistors and the charging voltage terminal of the first capacitor. means is provided, and when the voltage on the detection line side becomes lower than the charging voltage of the first capacitor, the first
A discharging means connected between the charging voltage terminal of the capacitor and the ground line operates to discharge the charging voltage of the first capacitor and charge the second capacitor to cause the thyristor to generate a trigger output voltage. Open phase circuit breaker. (2) The voltage comparison means and the discharge means are connected to the base via a diode with the charging voltage side of the first capacitor as the emitter, the ground line side as the collector, and the detection line side as the cathode. The open-phase circuit breaker according to claim 1, characterized in that it is a connected PNP transistor. (3) The voltage comparing means and the discharging means connect the connecting point of the voltage dividing resistors and the charging voltage terminal of the first capacitor to a first
The open-phase circuit breaker according to claim 1, characterized in that the capacitor is connected with a diode whose charging voltage end side is the anode side.