JPH09161627A - Control circuit for closing and opening switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of circuit parts in the switch control system of a control device installed in the state of being combined with a switch, and also to use a current changing-over contact of a low rating value. SOLUTION: A delay release capacitor 35 is connected in parallel to a current changing-over contact 34 for bypassing a current made to flow into a closing coil 21 at the beginning of closing operation to short-circuit a holding coil 22. With the circuit arrangement, when the current change-over contact 34 is opened to start electrifying the holding coil 22, a part of the current made to flow into the current change-over contact 34 as an overcurrent makes the charging current of the delay release capacitor 35, and for that reason, the current made to flow into the current change-over contact 34 can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switch control circuit of a control device installed in combination with a switch in a switch control system.

[0002]

2. Description of the Related Art A switch control circuit according to the prior art is shown in FIG. This circuit consists of a DC power supply 11 and a backflow prevention diode.
12, opening / closing contact 13, current switching contact 14, delay opening capacitor 15 for supplying current to the coil during momentary power failure, for limiting the inrush current to the capacitor when the power is turned on Inrush current limiting resistor 16, current flows through the inrush current limiting resistor 16 when charging the capacitor, capacitor discharging diode 17 to flow the charge of the capacitor to the coil at momentary power failure, etc. It is composed of a coil-1 (hereinafter referred to as a closing coil) 21 for maintaining the state and a coil-2 (hereinafter referred to as a holding coil) 22 for maintaining the state of the switch in the closed state. .

The closing control is performed in the following order. In the state before control, the contact 13 for making and opening is "OFF", and the contact 14 for switching current is "ON". First, the closing / opening contact 13 is set to “ON”. As a result, the power supply voltage is applied to the closing coil 21, and the switch (the pole switch in the figure) 20 is turned on. Next, the current switching contact 14 is turned off, the closing coil 21 and the holding coil 22 are connected in series, and the closing operation is completed. In this state, most of the voltage is applied to the holding coil 22.

[0004]

In such a control circuit according to the prior art, it is necessary to cut off the current flowing through the closing coil 21 by the current switching contact 14 when the switch 20 is turned on. It is necessary to have contacts. Normally, a contact having a capacity larger than the current value flowing in the steady state in the closing coil 21 is used in consideration of the safety factor. Also, in order to secure the delay release operation,
The inrush current limiting resistor 16, the delay opening capacitor 15 and the capacitor discharging diode 17 are required.

An object of the present invention is to close the closing coil 21.
It is to realize a switch control circuit having a small number of parts, which enables use of the current switching contact 14 having a current capacity equal to or less than the current value flowing in the steady state.

[0006]

According to the present invention, in order to solve the above-mentioned problems, a state in which a power supply voltage is applied to the closing coil in parallel with the holding coil and a holding coil in series with the closing coil are connected. A current switching contact for switching between a state in which a power supply voltage is applied and a capacitor for delay opening are connected.

With this connection, when the current switching contact is opened, the current flowing through the contact becomes a charging current for the delay opening capacitor, a part of which is connected in parallel. Since the current is shunted to, the transient current flowing through the contact is reduced accordingly. Also, because the closing coil limits the inrush current when charging the delay opening capacitor and protects the delay opening capacitor,
The inrush current limiting resistor is no longer necessary, and the capacitor discharging diode is also unnecessary.

[0008]

FIG. 1 is a circuit diagram showing an embodiment of a switch opening / closing control circuit according to the present invention. This circuit consists of a DC power supply 31, a backflow prevention diode 32, a closing / opening contact 33, a current switching contact 34, a delay opening capacitor 35 for supplying current to the coil in the event of a momentary power failure, open / closed state. It is composed of a closing coil 21 for putting the switch into the closed state and a holding coil 22 for holding the state of the switch in the closed state, and a current switching contact 34 and a delay opening capacitor 35 in parallel with the holding coil 22. Are connected.

In this embodiment, the current switching contacts
As 34, a contact having the same rated current capacity as the current capacity flowing in the closing coil 21 is used, but there is no problem in the closing operation. The input control is performed in the following order.
In the state before control, the making / opening contact 33 is “off” and the current switching contact 34 is “on”. First, contact for opening and closing
Turn 33 on. As a result, the power supply voltage is applied to the closing coil 21, and the switch (the pole switch in the figure) 20 is turned on. In this state, the current switching contact 34 is "ON"
In this state, there is no potential difference between both ends of the delay opening capacitor 35, and the capacitor is in an uncharged state. next,
When the current switching contact 34 is turned off, a potential difference is generated at both ends of the contact at the same time when the contact is opened, and accordingly, the delay opening capacitor 35 starts to be charged. In this case, the closing coil 21 acts as an inrush current limiting element. Since the charging current to the delay opening capacitor 35 shunts the current to the current switching contact 34, the current switching contact 34 is correspondingly divided.
Therefore, the current to the switch 34 decreases, and the current capacity of the current switching contact 34 decreases. When the charging of the delay opening capacitor 35 is completed, the current switching contact 34 is in the “OFF” state, and the steady current flows only in the coil section.
The closing operation ends. In this state, most of the power supply voltage is applied to the holding coil 22, as in the prior art.

In the prior art, the delay opening capacitor 15 is charged when the power source 11 is turned on.
In the case of the present invention, there is a difference that the delay opening capacitor 35 is charged by turning on / off the contact for opening / closing, but this is not a problem in practical use. On the other hand, when the closing / opening contact 33 is set to “off”, in the conventional technique, the delay opening capacitor 15 maintains the charged state (there is also a discharge circuit added if necessary). In the case of the present invention, since the electric charge of the delay opening capacitor 35 is discharged through the holding coil 22, there is no fear of maintaining the charged state.

[0011]

According to the present invention, by connecting the current switching contact 34 and the delay opening capacitor 35 in parallel to the holding coil 22, when the current switching contact 34 is turned "off", Since a part of the current flowing through the shunt is shunted as the charging current for the delay opening capacitor 35, a contact with a rated current capacity smaller than the contact current capacity determined by the current capacity flowing in the closing coil 21 when the switch is closed is used for current switching It can be used as the contact 34.

Further, since the closing coil 21 serves as an inrush current limiting element of the delay opening capacitor 35, the inrush current limiting resistor 16 is unnecessary, and at the same time, the capacitor discharging diode 17 is not required, and the number of parts is reduced. be able to. Further, when the closing / opening contact 33 is turned off, a delay opening capacitor 35, which is not shown in FIG.
No means for discharging the electric charge of

As described above, according to the present invention, it is possible to use a current switching contact having a small rated current capacity,
It is possible to realize a switch opening / closing control circuit with a small number of parts.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of a switch closing / opening control circuit according to the present invention.

FIG. 2 is a circuit diagram showing a switch opening / closing control circuit according to a conventional technique.

[Explanation of symbols]

 10, 30: Control device 11, 31: Power supply 12, 32: Reverse current prevention diode 13, 33: Make / open contact 14, 34: Current switching contact 15, 35: Delay opening capacitor 16: Inrush current limiting Resistor 17: Capacitor discharging diode 20: Pole switch 21: Closing coil 22: Holding coil

Claims (2)

[Claims] 1. A control circuit having a closing coil and a holding coil, which is installed in combination with a switch which performs a closing operation by switching the currents flowing through the coils, in parallel with the holding coil, and with the closing coil. The present invention is characterized by including a current switching contact for switching between a state in which a power supply voltage is applied and a state in which a holding coil is connected in series to a closing coil and a power supply voltage is applied, and a delay opening capacitor. Switch on / off control circuit. 2. The switch opening / closing control circuit according to claim 1, wherein the current flowing through the closing coil is divided into the current switching contact and the delay opening capacitor when the switch is opened. Switch opening / closing control circuit.