JPS605730A - Leakage 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 [Technical Field to which the Invention Pertains] The present invention relates to an improvement in an electromagnetic earth leakage breaker that does not require a control power source, and is capable of handling overcurrents and It is designed to instantly shut off short-circuit current.

[Prior art and its problems]

A conventional circuit of an electromagnetic earth leakage breaker that does not require a controlled flow will be explained with reference to FIG. This earth leakage breaker 1 has an input terminal 2.3 and an output terminal 4, 5, and one main circuit conductor 6 connecting the input terminal 2 and the output terminal 4 has an interruption part 7 and a bimetal 8 connected in series. The other main circuit conductor 9 has a breaker 10 and a bimetal 11 connected in series.

An annular zero-phase current transformer 12 is located around the outer periphery of the main circuit conductor 6.9. Reference numeral 13 denotes a device for removing earth leakage 4, which is operated by the current flowing through the zero-phase current transformer 12, and is connected to the breaker section 7.
6 with something that opens lO.

In the current leakage interrupter 1 having such a configuration, when a current leakage occurs on the unillustrated load side connected to the output terminal 4.5, an output is generated on the secondary side of the zero-phase current transformer 12.

Earth leakage 4 exterior #13 is activated, and the breaker section 7. IO will open, cutting off current to the load. On the other hand, when an overcurrent flows through the main circuit conductor 6.9, the overcurrent exception time T is determined according to the magnitude of the overcurrent (In is the rated value), as shown in Figure 2. This results in a so-called delayed trip characteristic.

In this earth leakage breaker, the time T becomes relatively short when the overcurrent becomes large, but the bimetal 8,
11, the time T settles down to a constant value. For this reason, it has a drawback that the cut-off time mainly in the short-circuit current region is relatively slow.

[Purpose of the invention]

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the above-mentioned drawbacks and to provide a circuit that can provide instantaneous interruption characteristics as an overcurrent exception characteristic with a simple configuration.

[Structure of the invention]

The present invention provides an electromagnetic earth leakage breaker that does not require a control power source, in which an arbitrary one-phase interruption of a main circuit conductor passing through a zero-phase current transformer is connected in parallel to the circuit between the output side and the load. and,
With a configuration in which a voltage limiting element and a resistor are connected in series outside the zero-phase current transformer, an instantaneous cutoff operation can be obtained against overcurrent and short-circuit current.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG.

Note that the same members as in FIG. 1 are designated by the same reference numerals, and explanations of those portions will be omitted. In the earth leakage breaker of the present invention,
Any one phase of the main circuit conductor 6.9, in this embodiment, the main circuit conductor 6, in parallel with the circuit between the output side of the breaker 7 and the output terminal 4, and of the zero-phase current transformer 12. Externally, a voltage limiting element 16 consisting of diodes 14, 15 connected in antiparallel to each other and a resistor 17 are connected in series.

In this circuit, the value of resistor 17 is the same as that of main circuit conductor 6.
The voltage limiting element 16 is set to a value that causes the voltage limiting element 16 to conduct when the load current flowing through the voltage limiter 9 exceeds the rated value. In addition, the positioning of the voltage limiting element 16 and the zero-phase current transformer 12 is such that when the voltage limiting element 16 conducts and current flows, this current becomes the primary input of the zero-phase current transformer 12 and removes the earth leakage 4. It is added where the action is performed.

In this earth leakage breaker 1 configured in this way, when the current flowing through the main circuit conductor 6.9 is the rated value In, the bimetals 8, 11 are connected to the breaker section 7.9. IQ is not operated, but if an overcurrent exceeding the rated value In flows, an overcurrent exception is made and the time T is determined depending on the magnitude of the overcurrent, as in the conventional example shown in Figure 1. Deburu.

As shown in FIGS. 4 and 5, now Hnxn=I
When a current of n' flows through the main circuit conductors 6 and 9, the voltage drop Va-b between points a and b in Fig. 4 is expressed as ■'a-b.
Then, when this V'a-b is equal to the conduction start voltage of the voltage limiting element 16, a current IIt flows through the circuit of the voltage limiting element 16. This current II.

becomes the primary input of the zero-phase current transformer 12.

As shown in FIG. 6, if the value of the resistor 17 is properly selected so that the current IP is larger than the primary input I't for operating the earth leakage 4 removing device 13, When the current ■'n flows through the main circuit conductor 6.9, the earth leakage 4 removing device 13 is activated instantly, and the main circuit conductor 6.9. This means that it will be possible to cut off the FIG. 7 shows the overcurrent exception characteristics of the earth leakage breaker 1 according to the present invention shown in FIG. For comparison with Fig. 2, overcurrent I
It can be seen that when In flows, it is abruptly cut off. In the above examples, the current It+ is Ip=(1,2−
1,5) It is preferable to set it to about XI'#, and I'n=
(IQ□~3r 000)

〔Effect of the invention〕

Since the present invention has the number of grooves as described above, in addition to the time-delayed tripping characteristics due to the thermal bimetallic type, instantaneous shut-off characteristics can be obtained, and the rated current is approximately 30 to 50 times higher. This has the advantage that the total shutoff time in the short flow region can be made extremely short. This allows application to circuits with larger short-circuit currents than conventional products.

In addition, if the number of circuit legs is selected appropriately, the rated commercial power of 3 to 5
It is also possible to instantaneously obtain the same 10 li, lr characteristics from a region approximately twice as large, and a great effect can be expected in ground fault protection and overcurrent protection for circuits with small overload tolerances, such as semiconductor devices. Since the configuration is simple, it also has the advantage of being easy to implement and inexpensive.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a conventional earth leakage interrupter, Fig. 2 is a line diagram showing the operating characteristics of the one shown in Fig. 1, Fig. 3 is a circuit diagram of an embodiment of the present invention, and Fig. 5 and 6 are diagrams showing the operating characteristics of the circuit shown in FIG. 3, and FIG. 7 is a diagram showing the operating characteristics of the circuit shown in FIG. 3. l: Earth leakage breaker, 6.9: Main circuit conductor, 7.10:
L and section, 8, 11: Bimetal. 12: Zero-phase current transformer, 13: Earth leakage 4 removal device, 14.15
: Diode, 16: Voltage limiting element, 17: Resistor. Patent applicant: Fuji Electric Manufacturing Co., Ltd. Representative Patent Attorney
Yoshihisa Naruoka Figure 5 Figure 6 -> In X n4* -+1nX n4s 2nd @ Figure 4 Jo-1 xn ellipse

Claims (1)

[Scope of Claims] l) In an electromagnetic earth leakage breaker that does not require a control power source, a circuit between the output side of the breaker of any one phase of the main circuit conductor passing through the zero-phase current transformer and the load. An earth leakage breaker characterized in that a voltage limiting element and a resistor are connected in series in parallel and externally to the zero-phase current transformer. 2. The earth leakage breaker according to claim 1, wherein the voltage limiting elements are composed of diodes connected in antiparallel to each other. 3) In the earth leakage breaker according to claim 1, the value of the resistor connected in series with the voltage limiting element is such that the voltage limiting element becomes conductive when the load current flowing through the main circuit conductor exceeds the rated value. An earth leakage breaker characterized by being set to a value that 4) In the earth leakage breaker according to claim 1, when the voltage limiting element conducts and current flows, the current becomes the primary power of the zero-phase current transformer and performs the earth leakage string disconnection operation. An earth leakage breaker characterized in that the voltage limiting element and the zero S current transformer are positioned so as to