JPH07209344A - Power source indicating lamp circuit of circuit breaker - Google Patents

Abstract

PURPOSE:To provide a long life, highly reliable power source display lamp circuit of circuit breaker, which can be lighted with constantly stable brightness regardless of high or low source voltage and can withstand high surge. CONSTITUTION:The power source indicating lamp circuit is provided with a rectifier circuit 7 connecting a power display-lamp circuit built in a circuit breaker 1 to a source side main circuit 2 and a light emitting diode (light- emitting element) 9 connected to the output side of the rectifier circuit 7 through a constant voltage diode (constant voltage device) 8. Voltage applied to the light-emitting diode 9 is regulated to be constant regardless of high/low source voltage applied to the circuit breaker 1 so that the light-emitting diode 9 is lighted with stable brightness for a long time to indicate the changed state of the source voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power indicator lamp circuit incorporated in a circuit breaker such as an automatic breaker for wiring.

[0002]

2. Description of the Related Art The above-mentioned auto breaker is equipped with a power indicator to prevent inadvertent electric shocks to workers during maintenance and inspection of wiring equipment, and the voltage applied state on the power side of the circuit breaker is turned on. It is displayed by lighting to call attention. FIG. 2 shows a power supply indicator circuit of a conventional circuit breaker. In the figure, 1 is a circuit breaker for three phases, 2 is a main circuit on the power supply side, 3 is a main circuit on the load side, and 4 is a main circuit. The circuit breaker contact 5 is a neon lamp as a power source indicator light. Here, the neon lamp 5 is connected in parallel between the U and W phases of the power source side main circuit 2 via the current limiting resistor 6, and if the power source side main circuit 2 is in a voltage applied state (live line), The neon lamp 5 is turned on to display that effect.

An ordinary low-voltage type automatic breaker can be used in a wiring circuit having a power supply voltage of 100 V to 600 V, and normally, in consideration of fluctuations in the power supply voltage, the lamp is turned on even at a power supply voltage of about 85 V. The neon lamp 6
The power supply indicator circuit is configured by selecting the specifications and the resistance value of the current limiting resistor 6.

[0004]

By the way, the following problems remain in the conventional power supply indicator light circuit which employs the neon lamp 5 as the power supply indicator light as described above. That is, the luminous intensity of the neon lamp 5 is determined by the discharge current of the lamp which is limited by the current limiting resistor 6, and when the resistance value of the current limiting resistor 6 is fixedly set, the discharge current of the neon lamp 5 becomes the characteristic of FIG. As shown in the figure, it increases or decreases according to the power supply voltage. For this reason, the lighting brightness of the neon lamp 5 changes when the power source voltage of the application destination of the circuit breaker is different. Moreover, since the life of the neon lamp is inversely proportional to the cube of the discharge current, there is a large difference in the life of the neon lamp between when the circuit breaker is used in the power supply circuit of 100 V and when it is used in the power supply circuit of 400 V, for example. Occurs,
If used in a high power circuit, the life of the neon lamp will be shortened. Regarding this point, the specifications of the neon lamp 5,
The life of the neon lamp 5 can be extended by changing the resistance value of the current limiting resistor 6 to an optimum value corresponding to the power supply voltage.
Such a method is not suitable for standardization of circuit breakers.

Further, when a surge voltage due to lightning or the like enters the circuit breaker from the power supply side, an excessive discharge current flows and the neon lamp is destroyed, which causes a problem in reliability. The present invention has been made in view of the above points, and its object is to solve the above problems, always turn on with a stable luminous intensity without being influenced by the magnitude of the power supply voltage, and a high surge withstanding capability can be obtained. It is to provide a power supply indicator circuit for a circuit breaker having a long life and high reliability.

[0006]

In order to achieve the above object, the power supply indicator circuit of the present invention comprises a rectifying means connected to a main circuit on the power source side and a constant voltage means on the output side of the rectifying means. It is assumed that the light emitting element and the light emitting element are connected together. Also,
In the above structure, it is preferable to use a constant voltage diode as the constant voltage means and a light emitting diode as the light emitting element.

[0007]

In the above construction, when the power source side is in the hot line state, the AC power source voltage applied to the power source side main circuit of the circuit breaker is rectified into direct current by the rectifying means, and the light emitting element is passed through the constant voltage means. Is lit to indicate that the power supply is in a charging state. In this case, even if the power supply voltage is high, the operating voltage applied to the light emitting element is limited to a constant value by the action of the constant voltage means, so that the luminous intensity does not change and maintains a constant brightness. Therefore, by optimizing the Zener voltage of the constant voltage diode, which is the constant voltage means, in advance according to the specifications of the light emitting element, it can be applied to wiring circuits having different power supply voltages without affecting the life of the light emitting element. .
Moreover, even if a surge voltage such as lightning is superimposed on the power supply voltage, the voltage applied to the light emitting element is maintained at a constant voltage, so that the light emitting element is not damaged.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, the same parts as those in FIG. 2 are designated by the same reference numerals. That is, in the embodiment of FIG. 1, the full-wave rectifier circuit 7 formed of a diode bridge is connected to the power-supply side main circuit 2 of the circuit breaker 1 between its UW phases, and its DC side is connected. A constant voltage diode 8 as a constant voltage means is connected between the output terminals of, and a light emitting diode 9 as a light emitting element is connected in parallel with the constant voltage diode 8. In addition, 10 is a protective resistor and 11 is a current limiting resistor.

With such a structure, the light emitting diode 9 is turned on when the voltage is applied to the power source side. In this case, the voltage applied to the light emitting diode 9 is limited to a constant voltage by the constant voltage diode 8, and as shown in the characteristic diagram of FIG. The current is constant and therefore the luminous intensity is also kept constant to maintain stable brightness. Further, even if a surge voltage due to lightning or the like is applied to the power source side, the constant voltage diode 8 does not cause an excessive voltage to be applied to the light emitting diode 9.

The circuit can be used not only as an AC circuit breaker but also as a DC circuit breaker.

[0011]

As described above, according to the power supply indicator circuit of the present invention, even if the circuit breaker is applied to the wiring circuit having different power supply voltage, the light emitting element is kept constant without being influenced by the power supply voltage. It is possible to maintain stable lighting for a long period of time while maintaining the luminous intensity of, and thereby to extend the power supply voltage range and prolong the life of the light emitting element. Moreover, it is possible to provide a power supply indicator circuit that has a long life and is highly reliable as compared with the conventional power supply indicator circuit, which can withstand the intrusion of surge voltage such as lightning.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a power supply indicator lamp of a circuit breaker according to an embodiment of the present invention.

[Fig. 2] Circuit diagram of the power supply indicator light of the conventional circuit breaker

FIG. 3 is a characteristic diagram showing the relationship between the power supply voltage and the current of the light emitting diode in FIG.

FIG. 4 is a characteristic diagram showing the relationship between the power supply voltage and the discharge current of the neon lamp in FIG.

[Explanation of symbols]

 1 Circuit breaker 2 Power supply side main circuit 7 Rectifier circuit 8 Constant voltage diode 9 Light emitting diode

Front page continuation (72) Inventor Kobashi Myobi Old 1-1 Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Fuji Electric Co., Ltd. Electric Co., Ltd.

Claims (3)

[Claims] 1. A power supply indicator light circuit for circuit interruption, which is incorporated in a circuit breaker to display a voltage application state on the power supply side, comprising rectification means connected to a main circuit on the power supply side and an output side of the rectification means. A power supply indicator circuit for a circuit breaker, comprising a light emitting element connected through a constant voltage means. 2. The power indicator light circuit according to claim 1,
A power supply indicator circuit for a circuit breaker, wherein the constant voltage means is a constant voltage diode. 3. The power indicator light circuit according to claim 1,
A power supply indicator circuit for a circuit breaker, wherein the light emitting element is a light emitting diode.