JPH10283903A - Electric leakage protective relay with buzzer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the miniaturization and low cost of a relay through using simple structure, by providing a resonant tube or a resonant box, having part of a resin-made case, on a buzzer to increase the sound volume of the buzzer. SOLUTION: In a resonant tube 10, a resonant chamber is composed of a circuit base plate 15; formed or resin integrally with a resin-made case 11, enveloping a buzzer 6, and loading a circuit part; and a small hole 12 opened in the resin-made case. The respect tube 10 constitutes the resonant chamber nearly closely fitted to a circuit base plate 15, also may be constitution closely fitted to the buzzer 6; and the volume of the resonant chamber, and the size of the small hole 12 are to be optimumly decided by the oscillation frequency of the buzzer. A relay for driving the buzzer can use a break contact structure of simple structure to realize miniaturization and inexpensiveness, by applying the constitution that when at SCR detected electric leakage is turned on, voltage is applied to a relay coil to break a power circuit, and concurrently actuate the buzzer increased sound volume by a resonant box.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Industrial applications] Built into household electrical appliances and industrial electrical equipment to prevent electric shock and protect equipment from leakage.
The present invention relates to an earth leakage protection relay that emits a buzzer sound and notifies the earth leakage state by sound.

[0002]

2. Description of the Related Art As shown in FIG. 5, a conventional buzzer notification type earth leakage protection relay has a main circuit contact having a c-contact structure, and when there is no earth leakage, the voltage on the power supply side is applied to the load side. When the power supply is detected and the leakage is detected, the voltage on the power supply side is directly supplied to the buzzer (the load side is cut off) so that the buzzer sound is obtained. Thus, the external shape was large and the cost was high.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide an earth leakage protection relay with a buzzer which has a small external shape, is inexpensive, and can generate a required buzzer volume.

[0004]

A buzzer is connected in series with a relay coil, and the buzzer is energized together with the relay coil to load the load circuit when the SCR is triggered by a short circuit. In the earth leakage protection relay having a circuit board configured to emit a buzzer sound at the same time as shutting off, a resonance cylinder or a resonance box having the resin case as a part is attached to the buzzer to increase the volume of the buzzer. With this, while using a small buzzer, the volume can be increased by the resonance cylinder or the resonance box having the resin case as a part, and a relay having a c-contact structure for driving the buzzer is used. It is possible to use a relay having a b-contact structure, which is unnecessary and has a simple structure, and can be configured as a whole small and inexpensively.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a first embodiment of a leakage protection relay with a buzzer according to the present invention, and FIG. 2 is an embodiment of a circuit block diagram of a leakage protection relay with a buzzer according to the present invention.

[0006] Reference numeral 1 in FIG. 2 denotes a zero-phase current transformer that uses the power lines 2 and 3 as primary conductors and detects a leakage current generated in a load circuit. Reference numeral 4 in FIG. 2 denotes an amplifying unit that triggers the SCR 5 when the leakage current exceeds a certain value. 2 in FIG.
Is a buzzer, 7 is a relay coil, voltage is applied when the SCR is triggered, a buzzer sound is generated and the relay is activated at the same time, and the relay contacts 8, 9 cut off the power circuit to protect the load circuit.

FIG. 1 illustrates the structure of a leakage protection relay having the circuit configuration described in FIG.

[0010] Reference numeral 10 in FIG. 1 denotes a cylindrical resonance tube molded of resin integrally with a resin case 11, surrounding the buzzer 6, and mounting a circuit component (not shown) of the circuit shown in FIG. 2. A resonance chamber is constituted by 15 and the small hole 12 opened in the resin case.

In FIG. 1, the resonance cylinder is a circuit board 15
The resonance chamber is formed in close contact with the buzzer, but may be in close contact with the buzzer. Here, the volume of the resonance chamber and the size of the small hole are optimally determined by the oscillation frequency of the buzzer.

In the circuit configuration shown in FIG.
When the CR 5 is turned on by the output of the amplifying unit 4, a voltage is applied to the relay coil 7 to open the relay contacts 8 and 9 to cut off the power circuit, and at the same time, a voltage is applied to the buzzer 6 and the buzzer sounds. . Therefore, FIG.
It is not necessary to use a relay having a c-contact structure as in the conventional example, and a small and inexpensive relay can be used.

However, the current flowing through the buzzer is limited by the current flowing through the relay coil, and it is difficult to obtain a current necessary to generate a sufficient volume.

Therefore, as shown in FIG. 1, by providing a resonance chamber in a shape surrounding the buzzer in a part of the resin case, it is possible to obtain a necessary sound volume, and as a whole a small and inexpensive earth leakage with a buzzer is provided. A protection relay is obtained.

In the present invention, for example, a small piezoelectric buzzer driven by a small direct current can be used.
The external shape can be reduced.

FIG. 3 shows a second embodiment of the structure shown in FIG. 1, in which a partition plate 1 is provided between a resin case 11 and a circuit board 15.
3, a resonance chamber is formed by the partition plate, a part of the resin case, the small holes 12, and the circuit board, and has the same effect as that of the first embodiment.

FIG. 4 shows a third embodiment of the structure shown in FIG. 1, in which a resonance chamber is constituted by a resin case 11, small holes 12, and a small board 16 separated from a circuit board 15.
This has the same effect as the first embodiment.

[0016]

As described above, according to the present invention, it is possible to provide an earth leakage protection relay with a buzzer, which is smaller in size, lower in cost, and can have a sufficient required volume as compared with the conventional example.

[Brief description of the drawings]

FIG. 1 is a block diagram of an earth leakage protection relay with a buzzer according to the present invention.

FIG. 2 is a view of a first structural embodiment of a leakage protection relay with a buzzer according to the present invention.

FIG. 3 is a view of a second embodiment of the earth leakage protection relay with a buzzer according to the present invention.

FIG. 4 is a view showing a third embodiment of the earth leakage protection relay with a buzzer according to the present invention;

FIG. 5 is a block diagram of a conventional earth leakage protection relay with a buzzer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Zero-phase current transformer 2 Power line 3 Power line 4 Amplifying part 5 SCR 6 Buzzer 7 Relay coil 8 Relay contact 9 Relay contact 10 Resonance cylinder 11 Resin case 12 Small hole opened in resin case 13 Partition plate 14 15 Circuit board 16 Small board

Claims (1)

[Claims] A buzzer is connected in series with a relay coil, and the buzzer is energized together with the relay coil to cut off a load circuit when an SCR is triggered by an electric leakage. An earth leakage protection relay having a buzzer, wherein a resonance chamber including the resin case as a part is attached to the buzzer to increase the volume of the buzzer.