JP2625814B2 - Power supply current switching circuit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply current switching circuit, and more particularly to a power supply current switching circuit for switching a current path of a DC current in power supply to a repeater in a branch communication line. .

[Conventional technology]

The prior art will be described with reference to FIG. Considering the case where power is supplied between the current source 5 and the current source 6 set in each terminal in FIG. 3, the relay operating current Io to the branch circuit is
With the ground as the return path, current source 5 → repeater 11C → first relay winding circuit 1A → first relay contact 1B−1 → repeater 11
A flows through the path of the current source 6. At this time, the winding circuit 1A of the first relay operates, and the contact 1A-1 of the first relay is switched from the a side to the b side. As a result, the current path as viewed from the current source 7 is, with the ground as a return path, the ground 4 → the first relay contact 1A-1 → the repeater 11B → the current source 7;
Power supply from That is, power supply to both stations between the current sources 5 and 6 and power supply to one station from the current source 7 are completed. When power is supplied between the current sources 5 and 7 at both stations, the winding circuit 1B of the first relay operates by the same operation as described above, and single-station power supply from the current source 6 becomes possible. As a result, repeaters 11A and 11
Current can be supplied to all of B and 11C, and the communication path 12 enables mutual communication between the communication terminal stations 8 and 9, between the communication terminal stations 9 and 10, and between the communication terminal stations 8 and 10.

Now, the output point A of the branch A and the current source 6 or the branch B
In the case where power supply becomes impossible due to some trouble between the output point B and the current source 7, power can be supplied to both stations through the remaining path. The communication path in this case is either between the communication terminal stations 8 and 9 or between the communication terminal stations 8 and 10.

[Problems to be solved by the invention]

In the above-described conventional power supply current switching circuit, when power supply from the current source 5 becomes impossible due to a failure of the repeater 11C or a cable in the middle for some reason, all of 11A, 11B, and 11C are used for the following three reasons. Will not be able to supply power to the repeater.

(1) The current sources 6 and 7 have the same polarity.

(2) Even if the input of the current source 7 is grounded and power is supplied from the current source 6 using the ground as a return path, the current flows in the reverse direction to the repeater 11B.

(3) When a current flows in the state of (2), the winding circuit 1A of the first relay operates, and the contact 1A-1 switches from the side a to the side b to cut off the current by itself. As described above, in the conventional circuit, when power supply from the current source 5 becomes impossible, current cannot be supplied to all power supply paths, and all communication paths are stopped.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate such a drawback and to provide means for supplying power to a normal path by two remaining current sources even when any power supply in each branch path is stopped. .

[Means for solving the problem]

The circuit according to the present invention has a single pole double throw contact having an operating current direction and an operating current value different from each other in a current switching circuit which branches and switches a current path of a direct current in two directions of a branch path A and a branch path B. The relay winding circuit of the first relay and the second relay having the single pole single throw contact is connected to the branch A
And a contact point of a first relay connected in series to the branch path B and connected to the branch path A, respectively.
Also, the contacts of the first relay connected to the branch path B connect and disconnect the branch path B corresponding to the non-operation and operation of the relay, respectively, and are connected so that the contact to be made during operation is grounded. Further, a single-pole / single-throw third relay is connected in series between the branch point of the branch A and the branch path B and the ground, and the contact of the second relay is connected in parallel with the contact of the third relay. It has the characteristic which consists of.

〔Example〕

 Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the basic configuration of the present invention.

The configuration of the embodiment shown in FIG. 1 is a winding circuit of a first relay of two relays having single pole and double throw contacts which are inserted into branch paths A and B and have different operating current directions and operating current values. 1A, 1B, a second relay winding circuit 2A, 2B of two relays having a single pole single throw contact, a third relay winding circuit 3, inserted between the branch point M and the ground 4, a branch path A, the contact 1B-1 of the first relay inserted in the branch A, and the contact 1A- of the first relay inserted in the branch path B
1. The second relay contact 2A-1, the second relay contact 2B-1 and the third relay contact 3-1 connected in parallel to each other and connected in series to the third relay winding circuit 3 It is configured with.

 Next, the operation of the embodiment shown in FIG. 1 will be described.

A branch point M branches into two branch paths A and B. The branch path A has a first relay winding circuit 1A and a second relay winding circuit different in operating current direction and operating current value. 2A and the break contact a of the contact 1B-1 of the first relay on the branch path B side are connected in series. On the other hand, as a configuration of the branch path B, the winding circuit 1B of the first relay and the winding circuit 2B of the second relay, and the break contact a of the contact 1A-1 of the first relay on the branch path A side are used. Connected in series, and the above contacts 1A-1 and 1B-1
Are the respective input points of the branch path A and the branch path B.

A third relay 3 and its contact 3-1 and a contact circuit in which a total of three contacts of the second relay contacts 2A-1 and 2B-1 are connected in parallel between the branch point M and the ground 4 are connected in series. It is said that the connection has solved the disadvantages of the prior art.

FIG. 2 is a circuit diagram partially showing a specific configuration of the embodiment of FIG. Hereinafter, the description of the embodiment will be continued with reference to FIG.

First, a normal operation in which no failure has occurred will be described.

When power supply is started between the current source 5 and the current source 6, the current is changed from the current source 5 → the relay point 11C → the winding circuit 2A of the second relay → the winding circuit 1A of the first relay → the relay 11A → the current It flows in the path of source 6.

At this time, only the winding circuit 1A of the first relay operates.
This is because the winding circuit 2A of the second relay is a diode 2A-D
Is connected in the forward direction with respect to the current direction, and the current flows on the 2A-D side and does not flow through the winding coil. When the winding circuit 1A of the first relay operates, the contact connection of the contact 1A-1 of the first relay changes from Ca to Cb, and the power supply path viewed from the current source 7 is grounded with the ground as the return path. → The contact 1A-1 of the first relay 1A → the repeater 11B → the current source 7, so that power can be supplied from the current source 7. Therefore, repeaters 11A, 11B, 11C
Can supply current.

When power supply is started between the current sources 5 and 7, only the first relay 1B operates in the same manner as described above, and the contact 1B-1 is connected to cb, so that the current source 6 The seen power supply path is ground 4 → contact 1B-1 of first relay 1B → repeater 11
A → current source 6 and power supply from current source 6 becomes possible.
As a result, a current can be supplied to all the repeaters, so that the communication terminal station 8-9, the communication terminal station 7-8, the communication terminal station 9
−10 mutual communication becomes possible.

Next, an operation when a failure occurs between the current source 6 and the output point A of the branch path A and power supply from the current source 6 becomes impossible will be described.

In this case, current is supplied to the repeaters 11B and 11C by supplying power between the current sources 5-7. Since the section including the repeater 11A is a failure section, there is no need to supply power. As a result, only the communication between the communication terminal stations 8-10 can be performed by the communication path 12.

Next, an operation when a failure occurs between the current source 7 and the output point B of the branch path B and power supply from the current source 7 becomes impossible will be described.

In this case, current is supplied to the repeaters 1A and 11C by supplying power between the current sources 5-6. Since the section including the repeater 11B is a faulty section, there is no need to supply power. As a result, only communication between the communication terminal stations 8-9 is enabled by the communication path 12.

Next, an operation when a failure occurs between the current source 5 and the input point C of the current switching circuit and power cannot be supplied from the current source 5 will be described.

In this case, the switch 13 is turned on and the input of the current source 7 is grounded. Thereafter, power supply is started from the current source 7 with a minute current. This minute power supply current, with the ground as the return path,
Switch 13 → repeater 11B → first relay contact 1A-1 →
The winding circuit 1B of the first relay → the winding circuit 2B of the second relay
→ The second relay winding circuit 2A → The first relay winding circuit
1A, the contact point 1B of the first relay 1B-1 flows through the relay 11A → 6. At this time, a reverse current flows through the repeater 11B.

The repeater 11B does not function as a communication repeater with respect to a minute current in the reverse direction, but has a characteristic that a DC current is possible.

The relay winding circuits operable by the above current are the winding circuit 2B of the second relay and the winding circuit 1A of the first relay. The operating current value of the winding circuit 2B of the second relay is Since the value is smaller than that of the winding circuit 1A of the first relay, the winding circuit 2B of the second relay operates first. As a result, the contact 2B-1 of the second relay operates, and the power supply current is applied to the ground with the return path being ground 4 → the winding circuit 3 of the third relay → the contact 2B-1 of the second relay → the second relay. Winding circuit 2A → 1st
1A → the contact 1B-1 of the first relay → the repeater 11A → the current source 6 so that the current flows along the path.

When the contact 2B-1 of the second relay operates, a current flows through the third relay 3, the third relay contact 3-1 turns on, and the current path between the ground 4 and the current source 6 is switched.
It is maintained even if 13 is turned off.

Thereafter, when the current from the current source 6 is increased to a value similar to the normal state, the winding circuit 1A of the first relay operates, and the first relay winding circuit operates similarly to the above-described operation when no failure occurs. The contact connection of the contact 1A-1 is switched to Ca, and the current source 7
From the view of the power supply path is ground 4 → contact 1A-1 of the first relay
→ The repeater 11B → the current source 7 and the power supply from the current source 7 becomes possible. Summarizing the above results, the feeding path from the current source 6 is grounded 4 → third relay winding circuit 3 → third contact 3-1 → second relay winding circuit 2A → first relay winding circuit 1A → first relay contact 1B-1 → repeater 11A → current source 6 and the power supply path from current source 7 is ground 4 with the return path being ground 4 → first relay Contact 1A-1 → repeater 11B → current source 7 and current source 5
Current can be supplied to the repeaters 11A and 11B even when power supply from the power supply becomes impossible. That is, communication between the communication terminal stations 9-10 can be secured.

〔The invention's effect〕

As described above, according to the present invention, the first and second two relays having different operating current directions and operating current values are connected in series to the branch path, and the third relay is connected between the branch point and the ground. By properly using the contacts of these relays,
Even if any branch line on the branch road becomes an obstacle, power can be supplied between the remaining two branch routes, and as a result, there is an effect that communication between normal branch routes can be secured.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the basic configuration of the present invention, FIG. 2 is a circuit diagram showing a specific configuration of the embodiment of FIG. 1 including a partial block diagram, and FIG. FIG. 3 is a block diagram illustrating a basic configuration of a power supply switching circuit of FIG. 1A, 1B: winding circuit of the first relay, 1A-1, 1B-1 ...
Contacts of the first relay, 1A-D, 1B-D, 2A-D, 2B-D... Diodes, 3... Third winding circuit of the relay, 3-1.
Third relay contact, 4... Ground 5-7... Current source, 8
10 Communication terminal station, 11A, 11B, 11C repeater, 12 communication path, 13 switch.

Claims (1)

(57) [Claims] 1. A current switching circuit for switching a current path of a DC current by branching in two directions, a branch path A and a branch path B, having a single pole double throw contact having an operating current direction and an operating current value different from each other. 1 relay and a relay winding circuit of a second relay having a single pole single throw contact are connected in series to the branch path A and the branch path B, respectively, and the contact of the first relay connected to the branch path A is The contacts of a first relay connecting the branch B to the branch B also connect and disconnect the branch B in response to the non-operation and operation of the relay, respectively, and ground the contact to be made during operation. And the third relay of single pole single throw is connected in series between the branch point of the branch path A and the branch path B and the ground, and the second relay is connected in parallel with the contact point of the third relay. Connecting the contacts of Feed current switching circuit according to claim.