JPH0828936B2 - Phase breaker - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an open-phase circuit breaker that detects an open phase of a single-phase three-wire power supply line and disconnects an electric circuit.

BACKGROUND ART Conventionally, as this type of open-phase circuit breaker for detecting an open phase of a single-phase three-wire type power supply line to cut off an electric path, there is one as shown in FIG. 3 and FIG. When the main contact S ₁ inserted in (A, N, B phases) and the main contact S ₁ are driven and the power supply and load are reversely connected, the trip coil of the main contact S ₁ is continuously energized. A normally closed auxiliary contact S ₂ ′ for preventing the open phase is provided, and the open phase detection control means detects the open phase based on the voltage of the electric path input through the detection line to detect the main contact S ₁ and It was designed to open the auxiliary contact S ₂ ′. However,
FIG. 3 In the conventional example, all the detection lines l _A , l _N and l _B for detecting the open phase of each phase are connected to the main contact S ₁ by internal wiring inside the open phase circuit breaker A. Since it was connected to the load side to detect abnormal voltage due to open phase, the detection lines l _A , l _N ,
There is a problem that only the open phase on the power supply side can be detected with respect to 1 _{B, and} the open phase due to loosening of the N phase of the circuit breaker cannot be detected.

On the other hand, as in the conventional example shown in FIG. 4, when the detection line l _N connected to the N phase is drawn out of the open circuit breaker A by the lead wire and external wiring is performed, the above problem is solved. can do. However, in such a conventional example, in the case of the reverse connection state in which the power source is connected to the load side terminal and the load is connected to the power source side terminal (however, the N-phase detection line is
l _N is connected to the load connection side), the main contact for circuit break
Even if S ₁ opens, a current flows through the externally wired N-phase detection line l _N , so that there is a problem that the circuit cannot be interrupted even if the main contact S ₁ opens. In addition,
In order to normally cut off the electric path even if it is reversely connected, it is necessary to add a new auxiliary contact to the N-phase detection line l _N , which causes a problem that the configuration becomes complicated and the cost becomes high. there were.

[Object of the Invention] The present invention has been made in view of the above points, and an object of the present invention is to enable reverse connection without increasing the number of contacts, and to simplify the configuration and reduce the cost. To provide a cheap phase breaker.

DISCLOSURE OF THE INVENTION (Structure) The present invention detects an open phase by an abnormal voltage of a single-phase three-wire power supply line and turns on a switch means by an open phase detection signal to turn off a trip coil of a main contact. In the open-phase circuit breaker in which the main contact inserted in the electric path is opened by exciting and exciting the trip coil, and the detection line connected to the N-phase electric path from the open-phase detecting means is externally wired, The one-shot circuit that uses the detection signal as a pulse signal is used to form the open-phase detecting means, and when the open-phase is detected, the trip coil is pulse-excited, and the open-phase detecting means is connected to the N-phase to the detection line By inserting a normally-closed auxiliary contact linked to the main contact, it is possible to reverse connection without increasing the number of contacts, and to provide a phase-break circuit breaker with a simple structure and low cost. .

(Embodiment) FIG. 1 shows an embodiment of the present invention, in which an open phase is detected by an abnormal voltage of a single-phase three-wire power supply line, and a switch means composed of a thyristor SCR is turned on by an open phase detection signal. Then main contact S ₁
Exciting the trip coil L, the main contact S ₁ inserted in the electric path is opened by exciting the trip coil L, and the detection line l _N connected from the open phase detecting means to the N-phase electric path is used as a lead wire. In the same open-phase circuit breaker as in the conventional example shown in FIG. 4, the open-phase detection means is formed by using the one-shot circuit MM ₁ that uses the open-phase detection signal as a pulse signal. The trip coil L is excited in a pulsed manner, and a normally closed auxiliary contact S ₂ interlocking with the main contact S ₁ is inserted in the detection line l _N connected to the N phase. In the embodiment, the open-phase detecting means is an IC (the part surrounded by the one-dot chain line)
The comparator CP detects the open phase by comparing the voltage V ₁ detected via the detection line l _N with the reference voltage Vs _1.
1 and a waveform shaping circuit that shapes the output of comparator CP ₁
Formed by WS, a delay circuit TD that delays the output of the open phase detection signal by an appropriate amount of time to prevent malfunction due to noise, and a one-shot circuit MM ₁ that pulse-processes the delayed open phase detection signal. Has been done. In addition, in the IC, an output circuit OT that pulse-wise triggers the thyristor SCR by the open-phase detection signal composed of the pulse signal output from the one-shot circuit MM ₁ , a constant current circuit SC, a diode bridge DB
Stabilizes the DC power source rectified by
A constant voltage circuit SV that supplies c and a leakage detection circuit are provided.The leakage detection circuit includes an amplifier AP that amplifies the zero-phase current transformer ZCT output, the amplifier AP output and the reference voltage Vs ₂ . It is composed of a comparator CP ₂ for comparing and detecting leakage, and a one-shot circuit MM ₂ .

The operation of the embodiment will be described below. Now, when the power supply and the load are normally connected to the open-phase circuit breaker A, the voltage V ₁ applied to the abnormal voltage detection terminal via the N-phase detection line l _N is as shown in FIG. ), The rectified voltage of the AC power supply having a uniform amplitude is normally divided by resistance and input. Here, when the open-phase occurs disconnected the power supply line of the N phase t ₀ time, A-phase, voltages V ₁ by the load state of the B-phase becomes a rectified voltage to be large and small alternately the voltages V ₁ The capacitor C ₁ connected to the terminal is discharged during the period when the amplitude becomes the reference voltage Vs ₁ or higher. Fig. 2 (b)
Indicates the voltage V ₂ of the terminal, and immediately after the discharging period ends, the charging period starts. When the voltage V _{2 at} this terminal becomes equal to or lower than the threshold voltage Vth ₁ of the waveform shaping circuit WS, the delay circuit TD connected to the terminal as shown in FIG. 2 (c).
Start charging the capacitor C ₂ of. Next, when the voltage V ₃ at the terminal becomes equal to or higher than the threshold voltage Vth ₂ after the delay time Td (300 ms in the embodiment), the open phase detection signal Vo as shown in FIG. 2D is output. When the open phase detection signal Vo becomes H level, the one-shot circuit MM ₁ is triggered and the open phase detection signal Vo 'consisting of a pulse signal is output. When the open-phase detection signal Vo 'is input to the output circuit OT, a certain time and on the thyristor SCR is triggered, pulsed energized to trip the main contact S ₁ and auxiliary contact S ₂ a tripping coil L Is released and turned off, and the single-phase three-wire type electric circuit is cut off.

It should be noted that, when the single noise N equal to or higher than the reference voltage Vs ₁ is superimposed on the voltage V ₁ , the voltage is restored to the original value after about Tn (Tn <Td), and the malfunction is prevented. Further, the abnormal voltage detector is designed to be operable by the circuit current flowing only when the resistor Rx is connected to the terminal.

Next, when the power source and the load are reversely connected to the open-phase circuit breaker A, the normally closed auxiliary contact S ₂ inserted in the N-phase detection line l _N is turned off when the open phase is detected. Unlike the conventional example in FIG. 4, the detection line l _N does not impair the function of interrupting the electric circuit due to sneaking in. Further, a _one- shot circuit MM ₁ is provided in the open-phase detecting means to trip the open-phase detection signal Vo ′ as a pulse signal to prevent continuous energization of the coil L.
Since the auxiliary contact S ₂ ′ of the conventional example can be omitted, the N-phase detection line
It is not necessary to increase the number of contacts in spite of providing the auxiliary contact S ₂ to be inserted in l _N, and by utilizing the same interrupting mechanism as in the conventional example, the open-phase circuit breaker A with a simple structure and low cost
Will be realized.

[Effects of the Invention] As described above, the present invention detects the open phase by the abnormal voltage of the single-phase 3-wire power supply line and turns on the switch means by the open phase detection signal to turn off the trip coil of the main contact. Energize and open the main contact inserted in the circuit by exciting the trip coil,
In the open-phase circuit breaker in which the detection line connected to the N-phase electric circuit from the open-phase detection means is externally wired, the open-phase detection means is formed using a one-shot circuit that uses the open-phase detection signal as a pulse signal. , The trip coil is excited in a pulsed manner when the open phase is detected, and a normally closed auxiliary contact interlocking with the main contact is inserted in the detection line connected from the open phase detection means to the N phase. It is possible to provide a phase-break circuit breaker that has a simple structure and a low cost because reverse connection can be made possible without increasing the number.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment of the present invention, FIG. 2 is an operation explanatory diagram of the above, and FIGS. 3 and 4 are schematic configuration diagrams of a conventional example. A is open phase breaker, S ₁ is the main contact, S ₂ auxiliary contact, l _N detection line, MM ₁ is a one-shot circuit.

Claims (1)

[Claims] 1. An open circuit is detected by an abnormal voltage of a single-phase 3-wire power supply line, a switch means is turned on by an open phase detection signal to excite a trip coil of a main contact, and an trip coil is excited. In the open-phase circuit breaker in which the main contact inserted in the electric path is opened and the detection line connected to the N-phase electric path from the open-phase detecting means is externally wired, the open-phase detection signal is a pulse signal. The phase loss detecting means is formed by using a shot circuit, the trip coil is excited in a pulsed manner at the time of phase loss detection, and a normally closed auxiliary contact interlocking with the main contact is inserted in the detection line connected to the N phase. The open-phase circuit breaker characterized by the above.