JPH0783566B2 - Switch circuit - Google Patents

Description

The present invention relates to a switch circuit for opening and closing a relay having a self-holding function.

[Prior Art] FIG. 2 shows a conventional switch circuit disclosed in JP-A-58-152329. The switch circuit is composed of a relay switch 4 and a remote control switch 7, both of which are connected via a power supply 3. Switch 40 of relay switch 4
Reference numeral 4 is for connecting and disconnecting the load 5 to and from the load power source 6, which is opened and closed by operating the remote control switch 7.

As shown in FIG. 2, in a general use state of the switch circuit, for example, two relay switches 4 and 4 ′ are connected in parallel to the input terminals 7 a and 7 b of the remote control switch 7 and are operated by the remote control switch 7. It is opened and closed all at once.

The relay switch 4 is a contact 4a with which the mover 4c selectively contacts.
And a relay 403 having 4b, and diodes 401 and 402 having polarities opposite to each other are connected to the contacts 4a and 4b. The other terminals of the diodes 401 and 402 are commonly connected and connected to one terminal 3a of the AC power supply 3. The other terminal of the power supply 3 is connected to the input terminal 7b of the remote control switch 7. The mover 4c of the relay 403 is connected to one terminal of the drive coil 405 of this relay, and the drive coil 405
The other terminal is connected to the input terminal 7a of the remote control switch 7. The switch 404 that opens and closes the load is designed to interlock with the mover 4c, and opens when the mover 4c is in contact with the contact 4a.

In the remote control switch 7, both input terminals 7a, 7b
Two diodes 9a and 9 with their anodes connected in common between
A series connection body of b and a series connection body of two thyristors 13a and 13b with the cathodes connected in common are connected in parallel. In addition, another diode 10a with the cathode connected in common,
In 10b, the respective anodes are capacitors 11a and 11b, respectively.
Is similarly connected between both input terminals 7a and 7b.
Changeover switch 8 whose mover is operated by a push button
The mover 803 is connected to the anodes of the diodes 9a and 9b, the contact 801 is connected to the cathodes of the diodes 10a and 10b through the resistor 12, and the contact 802 is connected to the cathodes of the thyristors 13a and 13b. The gate of thyristor 13a has resistance 1
4a is connected to the anode of the diode 10a, and the gate of the thyristor 13b is connected to the diode 10a via the resistor 14b.
It is connected to the anode of b.

Next, the operation of this conventional example will be described. Now, when the switch 404 is open and the mover 4c of the switch 403 is in contact with the contact 4a, the current is the power supply 3 → diode 401 →
Contact 4a → mover 4c → coil 405 → input terminal 7a → diode 9a → mover 808 → contact 801 → charging resistance 12 → diode 10
a → capacitor 11a → input terminal 7b → power supply 3 flow,
The capacitor 11a is charged to the polarity shown. However, no current flows after the capacitor 11a is sufficiently charged. In this state, when the mover 803 is pushed into contact with the contact 802, the charge voltage of the capacitor 11a is applied to the gate of the thyristor 13a via the resistor 14a. Therefore, the capacitance of the capacitor 11a and the resistance value of the resistor 14a are The time is set to the time constant determined by the time constant (the time constant is set to be sufficiently larger than the cycle of the power supply 3), and the coil 40
Current flows through 5. As a result, the coil 405 is excited to close the switch 404, and the mover 4c is switched to the contact 4b to maintain its state, and the load 5 is connected to the power supply 6.

Next, when the movable element 803 is released, the movable element 803 comes into contact with the contact 801 and the power source 3 → input terminal 7b → diode 9b → movable element 803 →
A circuit of the contact 801, the resistor 12, the diode 10b, the capacitor 11b, the first input terminal 7a, the coil 405, the mover 4c, the contact 4b, the diode 402, and the power supply 3 is formed, and the capacitor 11b is charged to the polarity shown in the figure. However, no current flows after the capacitor 11b is charged.

In this state, when the mover 803 is pushed to make contact with the contact 802, the charging voltage of the capacitor 11b is applied to the gate of the thyristor 13b via the resistor 14b, so that the thyristor 13b has the capacitance of the capacitor 11b and the resistor 14b. The coil is turned on for a time determined by a time constant (the time constant is set to be sufficiently larger than the cycle of the power supply), and a current flows through the coil 405. As a result, the coil 405 is excited and the switch 4
04 is opened, and the mover 4c is switched to the contact 4a to maintain its state by itself. When the mover 803 is returned to its original position, the mover 803
Contacts contact 801 again. That is, the switch 404 alternately opens and closes every time the mover 803 is operated.

[Problems to be Solved by the Invention] In the conventional switch circuit, the power source flowing through the coil 405 flows through the contact 801 or 802 of the changeover switch 8, and this current reaches several amperes, for example. In order to open and close such a comparatively large current, a switch 8 having a large capacity is required, which inevitably results in a large shape, which has been a restriction in reducing the size of the remote controller switch 7.

Moreover, in this conventional switch circuit, the direction of the current flowing through the circuit depends on which of the capacitors 11a and 11b is charged. That is, the capacitors 11a and 11b are charged by the voltages applied to the terminals 7a and 7b, respectively, but which of them is charged depends on the polarity of the voltage applied to the terminals 7a and 7b. For example, as shown by a dotted line in FIG. 2, another relay switch 4'is connected in parallel to the relay switch 4 and the relay switch 4 '
When the mover 4c ′ of the relay 403 ′ of 4 is in contact with the contact 4b ′ and the mover 4c of the relay 403 is in contact with the contact 4a, the AC power source of the power source 3 is applied to the circuit of the relay switch 4. A full-wave rectified current flows. As a result, capacitors 11a, 11b
Are both charged with the polarity shown. When the mover 803 contacts the contact 802 by operating the switch 8 in this state, both thyristors 13a and 13b are irregularly turned on, and the relays 403 and 403 'operate accordingly. Therefore, relay switch 4,4 '
Cannot be operated normally.

[Means for Solving the Problems] In a switch circuit composed of a relay switch and a remote control switch, first and second thyristors are connected in reverse polarity between first and second input terminals of the remote control switch. , One end of the capacitor is connected to the first input terminal, and the other end is connected to the mover of the switch composed of the mover and the first and second contacts with which the mover makes selective contact,
One end of the first resistor is connected to the first contact of the switch, the other end is connected to the gate of the first thyristor, one end of the second resistor is connected to the first input terminal and the other end is connected. A Zener diode and a light emitting element connected to the second contact of the switch, the anode of which is connected to the second input terminal and the cathode of which is connected to the second contact through the third resistor, and the light emitting element are connected to the first input terminal and the first input terminal. A photocoupler connected between the gates of the first thyristor and a light receiving element connected between the cathode of the zener diode and the gate of the second thyristor, and two contacts for selectively contacting the mover and the mover; Mover and second
The two contacts of the relay having the self-holding function, which is composed of the coil connected between the input terminals of the two diodes, are connected to the two diodes whose opposite ends are commonly connected to each other and are connected in common. An AC power supply is connected between the other end of the diode and the first input terminal.

[Operation] A relatively large current flowing through the coil 405 is controlled by the thyristor 13a or 13b, and only a relatively small charging / discharging current of the capacitor 11 flows through the switch 8. Also capacitors
11 is connected in series with Zener diode 15 and connected between both input terminals 70a, 70b, so both input terminals 70a, 70b
When the full-wave voltage of the AC power supply 3 is applied in the meantime, the polarity of the charging voltage of the capacitor 11 becomes equal to the polarity of the forward current of the Zener diode.

[Embodiment] FIG. 1 shows an embodiment of the switch circuit of the present invention. In the figure, the relay switch 4 has a relay 403 having contacts 4a and 4b which are switched by a mover 4c.
4b has diodes 401 and 402 whose polarities are opposite to each other.
Are connected. The other terminals of the diodes 401 and 402 are commonly connected and connected to one terminal 3a of the AC power supply 3. The other terminal of the power supply 3 is connected to the input terminal 70b of the remote control switch 70. The mover 4c of the relay 403 is connected to one terminal of the drive coil 405 of the relay 403, and the other terminal of the drive coil is the input terminal 70a of the remote control switch 70.
It is connected to the. The switch 404 for opening and closing the load is designed to interlock with the mover 4c, and the mover 4c contacts the contact 4a.
Open when in contact with.

In the remote control switch 70, the cathode of the thyristor 13a is connected to its input terminal 70a, and its anode is connected to the input terminal 70b. Also thyristor 13a
The light emitting element 16a of the photocoupler 16 whose anode is connected to the gate is connected between the gate and the input terminal 70b. A bypass capacitor 20a and a bias resistor 19a are further connected in parallel between the gate of the thyristor 13a and the input terminal 70b. The other thyristor 13b is connected between the input terminals 70a and 70b such that its anode is connected to the input terminal 70a, and a bias resistor 1 is connected between its gate and the input terminal 70a.
9b and bias capacitor 20b are connected in parallel. The cathode of the Zener diode 15 has an input terminal 70.
The light emitting element 16b of the photocoupler 16 is connected between its anode and the gate of the thyristor 13b so that its emitter is connected to the gate. In the push-button type changeover switch 8 that performs a switching operation by pressing the mover 803, the mover 803 is connected to the input terminal 70b via the capacitor 11, and its normally open contact 802 has the thyristor 14 via the resistor 14. It is connected to the gate of 13a. The normally closed contact 801 has a resistance of 1
It is connected to the cathode of the Zener diode 15 via 8 and to the input terminal 70b via the resistor 17.

Next, the operation of this embodiment will be described. In FIG. 1, the switch 404 is open, and the mover 4c of the switch 403 has the contact 4a.
When in contact with the power source 3 → diode 40
1 → contact 4a → mover 4c → coil 405 → input terminal 70a → zener diode 15 → resistor 18 → resistor 17 → input terminal 70b → power supply 3 circuit is formed, and the capacitor is passed through contact 801 of switch 8 and mover 803. 11 is charged. The value of the resistor 18 is set high enough so that the relay 403 does not operate due to the current flowing through the circuit. When the mover 803 of the switch 8 is pushed into contact with the contact 802 in this state, the charging voltage of the capacitor 11 is applied to the gate of the thyristor 13a via the resistor 14, and the thyristor 13a causes the capacitance of the capacitor 11 and the time constant of the resistor 14 to change. It is turned on for a time determined by (the time constant is set to be sufficiently larger than the cycle of the AC power supply 3), and a current is passed through the coil 405. As a result, the coil 405 is excited to close the switch 404, switch the mover 4c to the contact 4b, and maintain the state. As a result, the load 5 is connected to the AC power supply 6.

When the push button is released, the mover 803 comes into contact with the contact 801 and the power source 3
→ Input terminal 70b → Resistor 17 → Resistor 18 → Zener diode 1
5 → input terminal 70a → coil 405 → mover 4c → contact 4b → diode 402 → power supply 3 circuit is formed,
The capacitor 11 is charged via the mover 803 and the contact 801. However, the charging voltage becomes lower by the Zener voltage as compared with the case of being charged by the forward current of the Zener diode 15. The value of the resistor 18 is set high enough so that the relay 403 does not operate due to the current flowing through it.

In this state, when the push button is pressed again to bring the mover 803 into contact with the contact 802, the charging voltage of the capacitor 11 is applied to the light emitting element 16a of the photocoupler 16 via the resistor 14.
The light emitting element 16a emits light. As a result, the light receiving element 16b of the photocoupler 16 becomes conductive, a voltage equal to the Zener voltage of the Zener diode 15 is applied to the gate of the thyristor 13b, the thyristor 13b is turned on, and is determined by the capacitance of the capacitor 11 and the time constant of the resistor 14. The state is maintained for a time. At this time, the thyristor 13a does not turn on because the voltage applied to its gate has the opposite polarity. In that state, from the power supply 3 to the thyristor 13b → the coil 405 → the mover 4c →
A circuit from the contact 4b to the diode 402 to the power supply 3 is formed, the switch 404 is opened, and the state is maintained even after the push button 8 is released. That is, only one of the thyristors 13a and 13b is turned on depending on the polarity of the voltage charged in the capacitor 11.

Next, as shown by the dotted line in FIG. 1, for example, when two relay switches 4 and 4'are connected to the remote control switch 70, the mover 4c of each relay 403 has contacts 4a and contacts 4a different from each other. When in contact with 4b, current flows through the circuit of the remote control switch 70 in both positive and negative cycles of the power supply 3. The capacitor 11 repeats charging and discharging at every positive and negative cycle of the power source 3. However, the voltage between both terminals of the capacitor 11 is a zener diode when the input terminal 70b is positive and when the input terminal 70b is negative. 15 Zener voltage low.
Therefore, the capacitor 11 is charged so that the movable element 803 side is positive and the input terminal 70b is negative. When the push button switch 8 is pressed in this state and the mover 803 comes into contact with the contact 802, the thyristor 13a is turned on, and the current flows only in the direction indicated by the arrow I ₁ . As a result, the relay in which the mover 4c contacts the contact 4a
Only 403 operates to bring the mover 4c into contact with the contact 4b and close the switch 404. That is, both relay switches 4 and 4'are brought into the same state, and thereafter, the pushbutton switch 8 is operated to perform the same operation at the same time. In the above embodiment, the case where the number of the relay switches 4 is two has been described.

[Effect of the Invention] According to the present invention, a relatively large current flowing through the coil 405 of the relay switch 4 has a thyristor 13 whose gate input is opened and closed by the push button switch 8 of the remote control switch 70.
Since it is controlled by a or 13b, push button switch 8
A small current flows through the contacts 801 and 802. Therefore, the push button switch 8 may be small in size and small in capacity, and the remote controller switch 70 may be downsized.

Further, the capacitor 11 and the zener diode 15 are connected between the input terminals 70a and 70b of the remote control switch 70 by the push button switch 8
Therefore, the voltage applied to the capacitor 11 depends on the polarity of the zener diode, and the voltage when the zener diode is in the forward polarity is higher than the voltage when the zener diode is in the opposite polarity. It differs by the Zener voltage of the diode. Therefore, when a plurality of relay switches whose switching states are not the same are connected, when the AC voltage is applied to the capacitor 11, the polarity of the terminal voltage becomes equal to the polarity of the forward current of the Zener diode 15, and the pushbutton The thyristor that is turned on when the switch 8 is operated is specified. As a result, the relays 403 of all the plurality of relay switches 4 are switched to the same state.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a switch circuit according to the present invention, and FIG. 2 is a circuit diagram of a conventional switch circuit. In the figure, 3 is an AC power supply, 4 is a relay switch, 4a and 4b are contacts, 4c is a mover, 8 is a switch, 11 is a capacitor, 13a and 13b are thyristors, 14 is a resistor, 15 is a zener diode, and 16 is a photo. Coupler 16a is a light emitting element, 16b is a light receiving element, 17 and 18 are resistors, 70 is a remote control switch, 70 is a remote control switch, 70a and 70b are input terminals, 401 and 402 are diodes, 403 is a relay, 405 is a coil, 801 and 802 are contacts, and 803 is a mover. Is.

Claims (1)

[Claims] 1. A switch circuit constructed by a relay switch and a remote control switch, wherein first and second thyristors are connected in reverse polarity between first and second input terminals of the remote control switch, and one end is first. A capacitor connected to the input terminal of the switch, the other end of which is connected to the mover of the switch composed of the mover and the first and second contacts with which the mover makes selective contact, and one end of which is the first contact of the switch. And a second resistor connected to the gate of the first thyristor, the other end of which is connected to the first input terminal and the other end of which is connected to the second contact of the switch. , A Zener diode whose anode is connected to the second input terminal and whose cathode is connected to the second contact via the third resistor, and whose light emitting element is connected between the first input terminal and the gate of the first thyristor The light receiving element is a photocoupler connected between the cathode of the Zener diode and the gate of the second thyristor, two contacts at which the mover and the mover selectively contact, and between the mover and the second input terminal. A relay having a self-holding function, which is composed of connected coils, two diodes each having one end connected to the two contacts of the relay in opposite polarities and the other end commonly connected, and the common connection A switch circuit having an AC power supply connected between the other end of the diode and the first input terminal.