JPS6241539Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an operating time display circuit for displaying the operating time of a circuit breaker having a timed tripping mechanism controlled by an electronic circuit.

FIG. 1 is a block diagram showing an example of a conventional circuit breaker operating time display circuit. In the figure 1
is a line, 2 is a current transformer that detects the current on line 1, and 3 is a current transformer that detects the current on line 1.
4 is a switching element that operates in response to a signal from the timer circuit 3; 5 is an opening/closing mechanism; 6 is an operation display mechanism; and 7 is a tripping coil.

Next, to explain its operation, the current flowing in the line 1 is constantly detected by the current transformer 2, and the information is sent to the time limit circuit 3. When a current flows, one of the plurality of output terminals of the time limit circuit 3
outputs a control signal in accordance with the passage time of the overcurrent, turning on one of the connected switching elements 4. When one of the switching elements 4 is turned on, the tripping coil 7 connected thereto is energized, and the opening/closing mechanism 5 is operated by the attractive force of this coil, thereby cutting off the line 1. At this time, an operation display mechanism 6 is connected to the anode of the switching element in order to display which switching element among the switching elements 4 has operated.

Since the conventional operation display device is configured as described above, a mechanical self-holding device is required because the overcurrent detection circuit loses power as soon as the opening/closing mechanism 5 opens. This required large and expensive items such as release coils. Furthermore, it was difficult to reset automatically due to mechanical self-holding.

This idea was made in order to eliminate the drawbacks of the conventional ones as mentioned above, and by combining a simple circuit and multiple diodes for reverse current blocking, it is possible to easily obtain a single power source from an external source. The object of the present invention is to provide a time display circuit that can display operation.

An embodiment of this invention will be described below with reference to the drawings.
FIG. 2 is a circuit diagram showing an embodiment of this invention, in which the same reference numerals as in FIG. Reference numeral 12 designates an operation display device 13, which will be described later, and a backflow blocking diode corresponding to an external power supply 14; 13, an operation display device; and 14, an external power supply.

Next, the operation of the circuit shown in FIG. 2 will be explained. When a current exceeding a predetermined allowable value flows through the line 1, the timer circuit 3 operates, and when the switching element 4 is turned on, the tripping coil 7 is activated.
A current flows to open the opening/closing mechanism 5. At this time, the external power supply 14 connects the operating switching element 4 to the series circuit of the operation display device 13 and the reverse current blocking diode.
One of the operation display devices 13 operates by passing a current through the terminal. While all the switching elements 4 are in the OFF state, a voltage is applied from the external power supply 14 to the switching elements 4 through the operation display 13 and the diode 12, but since the switching elements 4 are in the OFF state, none of the operation display devices 13 Do not work. Further, the voltage of the external power supply 14 is not applied to the time-limited tripping coil 7 due to the diode 11, and the voltage to the tripping coil 7 is not applied to the external power supply 14 due to the diode 12. There is no influence from the power supply 14.

This invention has the above-mentioned configuration, and since power is supplied to the operation display device 13 from the external power source 14 even after the opening/closing mechanism 5 is opened, and continuous display can be performed, there is no need to use a release coil or the like as in the past. There is no need for a self-holding device, so an inexpensive device such as a lamp or light-emitting diode can be used, and when there is a request to set up a sequence externally, a contact relay etc. can be used. It can be designed to control the sequence.

As described above, according to this invention, an inexpensive operation display device can be obtained by adding multiple diodes for backflow blocking and a simple circuit, and it is also possible to output contact signals in addition to displaying. Therefore, the operation display circuit can be configured in any location.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing an example of a conventional device; Figure 2 is a circuit diagram showing an example of a conventional device;
The figure is a circuit diagram showing an embodiment of this invention. 1...Line, 2...Current transformer, 3...Timed circuit,
4... Switching element, 5... Opening/closing mechanism, 6...
...Operation display mechanism, 7...Trip coil, 1
1, 12... Diode for backflow blocking, 13...
Operation display device, 14...External power supply. Note that the same reference numerals in each figure indicate the same parts.

Claims (1)

[Scope of utility model registration request] a plurality of switching elements to which the control signals from the output terminals of the time limit circuit are input, a plurality of diodes for preventing reverse current which are connected in series to the anode sides of the plurality of switching elements, a trip coil energized by a circuit in which a plurality of sets of series circuits of the diodes and the corresponding switching elements are all connected in parallel, and an output circuit in which a reverse current blocking diode and an operation indicator device are connected in series to each of the plurality of switching elements, the output circuit being connected in series between a common power source and each of the corresponding switching elements.