JPH05232155A - Announcing device - Google Patents

Abstract

PURPOSE:To announce information to the outside reliable and reduce power supply capacity of a power supply circuit for miniaturization. CONSTITUTION:The output voltage of a power supply circuit 6 for rectifying and smoothing an AC voltage through an impedance element 62 is applied to a series circuit of a self-hold switching element 4 and an announcing device driven by current application. Then, a voltage is applied to the input of the power supply of a signal processing circuit 3 which drives a switching element 4 through a Zener diode 7 with a Zener voltage exceeding a voltage which is obtained by subtracting a minimum operating voltage of the signal processing circuit from the output voltage of the power supply circuit whose voltage is dropped due to supply of power to the announcing device 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an informing device for informing an alarm or a display after inputting an input signal such as a leakage signal or an overcurrent signal and discriminating a level.

[0002]

2. Description of the Related Art This notification device includes a leakage notification device that detects a leakage current flowing in an electric path connecting an AC power source and a load and issues an alarm or display to the outside.

This earth leakage alarm device inputs the secondary output of a zero-phase current transformer interposed in an electric circuit to a signal processing circuit to determine the level by delaying and discriminating and responding to the output signal of the signal processing circuit. The switching element is operated to energize an indicator such as a display, an alarm, or an external notification relay to notify of a leak.The signal processing circuit and the annunciator show the AC voltage of the electric circuit via an impedance element. Power is supplied from the power supply circuit for rectifying and smoothing.

[0004]

However, in the above notification device, the power supply circuit needs to supply power to both the signal processing circuit and the notification device when the signal processing circuit drives the switching element. Therefore, it is necessary to equip the power supply circuit with a power supply capability that considers the power consumption of both.
It was a factor of increasing the size.

If the power supply capability of the power supply circuit is forcibly suppressed, if the indicator is, for example, a display, the luminous intensity is lowered, and if it is, for example, an alarm, the volume is lowered and the discrimination becomes difficult. For example, if an external notification relay is used, the operation becomes unstable, and there is a risk that reliable operation cannot be ensured.

The present invention has been made in view of the above circumstances, and an object of the present invention is to make it possible to reduce the power supply capacity of a power supply circuit and to reduce the size while ensuring a notification operation to the outside. To provide a device.

[0007]

In order to solve such a problem, the alarm device of the present invention is provided with a power input of a signal processing circuit,
The Zener diode having a Zener voltage equal to or higher than a voltage value obtained by subtracting the minimum operating voltage of the signal processing circuit from the output voltage of the power supply circuit, which has dropped due to energization of the alarm, is connected in series.

[0008]

In this leakage detecting device, the power supply circuit supplies power only to the signal processing circuit when the input signal is monitored, and when the signal processing circuit discriminates the level of the input signal and drives the switching element, the output of the power supply circuit is output. Since the voltage drops and the power supply to the signal processing circuit is stopped by the Zener diode and the power supply circuit supplies power only to the alarm,
The power supply capability of the power supply circuit can ensure a reliable operation only by providing a capacity that satisfies the larger one of the power consumption of the signal processing circuit or the power consumption of the alarm device.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.

A zero-phase current transformer 2 is installed in the electric line 1 connecting the AC power source 11 and the load 12, and when a leakage current such as a leak current or a ground fault current occurs in the electric line 1, the zero-phase current transformer 2 is Load resistance
Generates output voltage at 21.

The output voltage of the zero-phase current transformer 2 is input to the signal processing circuit 3, and the signal processing circuit 3 discriminates the level of leakage of the electric circuit 1 and outputs a signal. For specific level discrimination, the input signal is compared with a predetermined value to charge / discharge the capacitor 31, and the voltage of the capacitor 31 is compared with a predetermined value to perform time delay and discrimination. The signal processing circuit 3
An input resistor 32, a noise absorbing capacitor 33, and an input voltage limiting diode 33 are connected to the input of the.

The output signal of the signal processing circuit 3 is input to the self-holding type switching element 4 via the input resistor 41 to drive the switching element 4. This switching element 4
Is connected in series with an indicator such as a light emitting diode or a lamp, an alarm such as a buzzer or a bell, or an alarm 5 such as an external alarm relay. When the switching element 4 is turned on, the alarm 5 is energized to perform an alarm operation. I do.

The series circuit of the switching element 4 and the alarm device 5 is connected in parallel to the smoothing capacitor 61 of the power supply circuit 6.

In the power supply circuit 6, the voltage of the electric circuit 1 is dropped through an impedance element 62 such as a resistor or a capacitor and then rectified by a full-wave rectifier 63 and smoothed by a smoothing capacitor 61. In this embodiment, the rectification is performed after the voltage is dropped, but the voltage may be dropped after the rectification.

Further, the smoothing capacitor 61 of this power supply circuit 6
The power input of the signal processing circuit 3 is connected in parallel via the Zener diode 7.

The Zener diode 7 connected in series to the power supply input of the signal processing circuit 3 is less than or equal to the voltage obtained by subtracting the minimum operating voltage V2 of the signal processing circuit 3 from the output voltage V1 of the power supply circuit 6 in the monitoring state of the input signal. In addition, the Zener voltage V4 is greater than or equal to the voltage value obtained by subtracting the minimum operating voltage V2 of the signal processing circuit 3 from the output voltage V3 of the power supply circuit 6 that has dropped due to the energization of the alarm device 5.

Of course, in order to ensure that the operation of the signal processing circuit 3 is stopped, the Zener voltage of the Zener diode 7 is set.
V4 is the power supply circuit 6 in which the voltage has dropped due to the energization of the alarm 5.
It is desirable that the output voltage is V3 or higher.

Further, a series circuit of a reset switch 8 and a resistor 81 having a low resistance value is connected in parallel to the smoothing capacitor 61 of the power supply circuit 6, and the voltage of the smoothing capacitor 61 is once lowered by closing the reset switch 8. The operated switching element 4 is restored.

The operating state of the alarm device will now be described with reference to FIG. 2. Before the time t1 when the switching element 4 is turned on by the output signal of the signal processing circuit 3,
Since the switching element 4 is in the off state, no current flows through the alarm 5 as shown in FIG. 2 (a), and power is supplied only from the power supply circuit 6 to the signal processing circuit 3 as shown in FIG. 2 (b). Be done. At this time, the output voltage of the power supply circuit 6 as shown in Fig. 2 (c).
V1 is higher than the sum of the minimum operating voltage V2 of the signal processing circuit 3 and the Zener voltage V4 of the Zener diode.

Further, when the switching element 4 is turned on at time t1, the output of the power supply circuit 6 drops in voltage due to the action of the impedance element 62 of the power supply circuit 6, and FIG.
As shown in (c), the output voltage becomes V3, and this output voltage V3 becomes lower than the sum of the minimum operating voltage V2 of the signal processing circuit 3 and the Zener voltage V4 of the Zener diode.
The power supply to the signal processing circuit 3 is stopped as shown in FIG.
As shown in (a), a current flows through the alarm device 5 to perform the alarm operation.

By this operation, the power supply capacity of the power supply circuit 6 need only be provided with a capacity that satisfies the power consumption of the signal processing circuit 3 or the alarm device 5, whichever is larger. ..

In the above-described embodiment, the leakage alarm device is used, but various analog signals as well as digital signals may be level-discriminated and notified, and the invention is not limited to this.

[0023]

As described above, according to the alarm device of the present invention, a voltage obtained by subtracting the minimum operating voltage of the signal processing circuit from the output voltage of the power supply circuit, which has a voltage drop due to energization of the alarm, is input to the power input of the signal processing circuit. Since a Zener diode having a Zener voltage equal to or higher than the value is connected in series, the power supply circuit supplies power only to the signal processing circuit in the monitoring state of the input signal, and the signal processing circuit discriminates the level of the input signal and drives the switching element. In this state, the output voltage of the power supply circuit drops and the power supply to the signal processing circuit is stopped by the Zener diode, and the power supply circuit supplies power only to the alarm. It is possible to secure a reliable operation only by providing a capacity that satisfies the larger one of the power consumption and the power consumption of the alarm device. Power supply capacity of the power supply circuit with a reliable ones notifying operation to the downsizing can be achieved by small.

[Brief description of drawings]

FIG. 1 is a circuit block diagram showing an embodiment of a notification device of the present invention.

FIG. 2 is an operation explanatory diagram of FIG.

[Explanation of symbols]

 1 Circuit 11 AC power supply 3 Signal processing circuit 31 Capacitor 4 Switching element 5 Notification device 6 Power supply circuit 61 Smoothing capacitor 62 Impedance element 63 Full wave rectifier 7 Zener diode

Claims (1)

[Claims] 1. An output voltage of a power supply circuit for rectifying and smoothing an AC voltage through an impedance element, which is responsive to a power supply input of a signal processing circuit for discriminating a level of an input signal and outputting the signal, and an output signal of the signal processing circuit. In the notification device applied to the self-holding type switching element and the series circuit of the alarm driven by energization, the output of the power supply circuit in which the voltage drops due to the energization of the alarm is input to the power input of the signal processing circuit. A notification device characterized in that a Zener diode having a Zener voltage equal to or higher than a voltage value obtained by subtracting the minimum operating voltage of the signal processing circuit from the voltage is connected in series.