KR101096920B1 - Solenoid coil monitoring apparatus using constant current circuit - Google Patents

Abstract

The present invention relates to a solenoid coil monitoring apparatus using a constant current circuit for measuring the resistance change of the solenoid coil to monitor the abnormality of the solenoid coil.
The present invention relates to a solenoid coil monitoring apparatus using a constant current circuit connected in parallel to a solenoid coil to monitor the solenoid coil, the parallel connection to the solenoid coil and constant regardless of the control power supply for supplying power to the solenoid coil. A constant current circuit configured to flow a monitoring current; A resistor configured to be connected in series with the constant current circuit; And a monitoring voltage applied to both ends of the resistance by the monitoring current flowing through the resistance, and comparing the monitoring voltage measured according to whether the solenoid coil is abnormal with a preset reference voltage to determine whether the solenoid coil is abnormal. A controller for determining; It provides a solenoid coil detection device using a constant current circuit comprising a.

Description

Solenoid coil monitoring device using constant current circuit {SOLENOID COIL MONITORING APPARATUS USING CONSTANT CURRENT CIRCUIT}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solenoid coil monitoring device. In particular, a constant current circuit and a resistor connected to a solenoid coil in parallel measure a voltage according to a resistance change of a solenoid coil, and use the same to determine whether a solenoid coil is abnormal. The present invention relates to a monitoring device for a solenoid coil using a constant current circuit for monitoring.

In general, the solenoid is a device made by winding a conductive coil in a dense and uniform cylindrical shape. When a current flows through the coil, the outside of the cylinder has a magnetic field of almost zero and the inside has a relatively uniform magnetic field. At this time, the magnitude of the internal magnetic field is proportional to the magnitude of the current flowing through the coil and is proportional to the number of turns per unit length.

These solenoids are used for opening and closing the breaker in the power system. For example, an air circuit breaker (ACB) or a vacuum circuit breaker (VCB) is a device that protects circuits and facilities by shutting off power to various accidents occurring in the power system, and is opened and closed by solenoid coils. The operation is performed. If the solenoid coil fails, this breaker will malfunction and cause serious problems in the power system. Therefore, it is very important to monitor the solenoid coil abnormally in real time.

Conventionally, since a device for monitoring an abnormality of a solenoid coil installed in a circuit breaker is not provided, an operator can confirm the failure of the solenoid coil only when the circuit breaker does not operate normally due to disconnection or short circuit of the solenoid coil. As a result, the solenoid coil is inspected and replaced only after the equipment to be protected by an accident has been damaged by overpower, which prevents a large accident.

In order to solve this problem, a solenoid coil monitoring circuit for opening and closing a circuit breaker has been proposed as shown in FIG. 1. 1 is a circuit diagram showing a conventional circuit breaker opening and closing solenoid coil monitoring circuit. Referring to FIG. 1, when the switch 1 is turned off, the control power supply Va is supplied to the solenoid coil 2 through the first, second and third resistors R1, R2, and R3 to monitor the current Ib. Will flow. Since the monitoring current Ib is a very small value compared to the solenoid operating current Ia by the resistors R1 to R3, the solenoid coil 2 cannot be operated by the monitoring current Ib. When the solenoid coil 2 is in a normal state, the monitoring voltage Vb applied to both ends of the monitoring current Ib and the second resistor R2 maintains a constant level. However, when the solenoid coil 2 is disconnected, the solenoid coil ( The resistance of 2) changes so that the monitoring current Ib and the monitoring voltage Vb change. The comparator 3 compares the monitoring voltage Vb and the reference voltage Vref, and determines whether the solenoid coil 2 is normal or abnormal using the comparison result in the determination unit 4.

However, in the above-described conventional solenoid coil monitoring circuit, the internal resistance of the solenoid coil 2 is very small compared to the first to third resistors R1 to R3, so that the monitoring current Ib is the control power supply and the first to third resistors R1. Is determined by R3). That is, when the control power supply is constant, the monitoring current Ib is controlled by the first to third resistors R1 to R3. Therefore, in the case of a solenoid coil using another control power supply Va, the monitoring current Ib changes in proportion to the control power supply Va. In order to cope with this, it is troublesome to change the first to third resistors R1 to R3 so that the monitoring current Ib is kept constant or to change the reference voltage of the comparator 4. In other words, there is a problem that a dedicated supervisory circuit must be used depending on the type of solenoid coil 3 with different control power sources.

The present invention has been proposed to solve the problems of the prior art, a constant current to measure the monitoring current for measuring the abnormality of the solenoid coil using a constant current circuit, by using this constant current to monitor the abnormality of the solenoid coil It is an object of the present invention to provide a solenoid coil monitoring device using a circuit.

In addition, an object of the present invention is to provide a solenoid coil monitoring apparatus using a constant current circuit that can monitor whether the solenoid coil is abnormal regardless of the type of the solenoid coil having a different control power source.

The present invention for achieving the above object,

A solenoid coil monitoring apparatus using a constant current circuit connected in parallel with a solenoid coil to monitor the solenoid coil, wherein a constant monitoring current flows independently of a control power supply connected to the solenoid coil in parallel and supplying power to the solenoid coil. A constant current circuit configured to; A resistor configured to be connected in series with the constant current circuit; And a monitoring voltage applied to both ends of the resistance by the monitoring current flowing through the resistance, and comparing the monitoring voltage measured according to whether the solenoid coil is abnormal with a preset reference voltage to determine whether the solenoid coil is abnormal. A controller for determining; It provides a solenoid coil detection device using a constant current circuit comprising a.

In an embodiment of the present invention, the constant current circuit and the resistor are preferably set so that the supervisory current flows small enough to not drive the solenoid coil.

In an embodiment of the present disclosure, the control unit compares the fluctuation range of the monitoring voltage with the preset fluctuation range of the reference voltage and the solenoid coil is abnormal when the fluctuation range of the monitoring voltage is out of the fluctuation range of the reference voltage. It is preferable to judge that to be.

By using the solenoid coil sensing device using the constant current circuit according to the present invention, by connecting a constant current circuit in parallel with the solenoid coil so that a constant current flows by the constant current circuit at all times, only the state of the solenoid coil can be monitored without the influence of other elements. You can do that.

In addition, when the solenoid coil monitoring apparatus using the constant current circuit according to the present invention is used, even if the input control power is different from the solenoid coil, it is possible to monitor whether the solenoid coil abnormality without changing or adding the circuit.

1 is a circuit diagram showing a conventional solenoid coil monitoring circuit.
2 is a block diagram showing a solenoid coil monitoring apparatus using a constant current circuit according to an embodiment of the present invention.
3 is a circuit diagram exemplarily illustrating a constant current circuit according to an exemplary embodiment of the present invention.
Explanation of symbols on the main parts of the drawings
110: constant current circuit 120: resistance
130: control unit

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In the description of the present invention, detailed descriptions of well-known functions or configurations will be omitted when it is determined that the detailed descriptions may unnecessarily obscure the subject matter of the present invention.

The solenoid coil monitoring apparatus using the constant current circuit according to the present invention is preferably applied to monitor the circuit breaker opening and closing solenoid coil used in the power system in real time. This breaker detects abnormal current flow and blocks it. There are two typical abnormal current flows. One is an increase in current flow due to an overload, short circuit, etc. in a circuit, and a wired circuit breaker (MCCB) may be used to block the current flow. Wiring breakers are used in place of the knife switches and fuses of the old toad house and compensate for the need to replace the fuses. The other is a short circuit, in which current flows between the ground and the current supply terminals, which are made for safety because of poor insulation.

The solenoid coil monitoring apparatus using the constant current circuit according to the present invention may be applied to, for example, a solenoid coil of an air circuit breaker (ACB) or a vacuum circuit breaker (VCB). Hereinafter, a monitoring device of a solenoid coil for opening and closing a circuit breaker will be described for convenience of description of the present invention. However, this is only one embodiment of the present invention and it will be apparent from the following description that the solenoid coil monitoring device of the present invention can be applied to a device to which the solenoid coil is applied.

Hereinafter, the solenoid coil monitoring apparatus using the constant current circuit according to the present invention will be described in more detail.

2 is a block diagram showing a solenoid coil monitoring apparatus using a constant current circuit according to an embodiment of the present invention.

2, the solenoid coil monitoring device 100 using a constant current circuit according to an embodiment of the present invention is connected in parallel to the solenoid coil 102 connected in series with the switch 101. More specifically, the solenoid coil monitoring device 100 is connected to the solenoid coil 102 in parallel and a constant current circuit 110 configured to flow a constant current, a resistor 120 connected in series to the constant current circuit 110 and The controller 130 includes a controller 130 that determines whether the solenoid coil 102 is abnormal by comparing the monitoring voltage Vb applied to both ends of the resistor 120 with the preset reference voltage Vr.

The solenoid coil 102 is connected in series with the switch 101 so that a control power supply Va is applied according to the operation of the switch 101 to determine the current flowing on the solenoid coil 102. That is, as shown in FIG. 2, when the switch 101 is turned on, the control power supply Va is applied to the solenoid coil 102 so that the operation current Ia flows through the solenoid coil 102. At this time, the same control voltage Va is applied to both ends of the constant current circuit 110 and the resistor 120.

On the other hand, when the switch 110 is off, the control power supply Va is applied to the solenoid coil 102 through the constant current circuit 110 and the resistor 120 so that the monitoring current Ib flows through the solenoid coil 102. At this time, the constant current circuit 110 and the resistor 120 are set such that the monitoring current Ib has a value very small compared to the operation current Ia. Therefore, the monitoring current Ib has a very small value compared to the operating current Ia by the constant current circuit 110 and the resistor 120, and the solenoid coil 102 cannot be operated by the monitoring current Ib.

When the solenoid coil 102 is in a normal state, the monitoring current Ib and the monitoring voltage Vb across the resistor 120 maintain a constant level, but the solenoid coil 102 is abnormal due to disconnection or short circuit. In the state, a change occurs in the internal resistance value of the solenoid coil 102, so that the monitoring current Ib and the monitoring voltage Vb change. In other words, the normal solenoid coil 102 maintains a constant resistance value and the monitoring current Ib and the monitoring voltage Vb maintain a constant range of values. However, when the solenoid coil 102 is disconnected, the monitoring current Ib does not flow and the monitoring voltage Vb has a value close to zero. In addition, when the solenoid coil 102 is short-circuited, the monitoring current Ib is greatly increased and the monitoring voltage Vb is also very large.

The controller 130 measures the monitoring voltage Vb applied to both ends of the resistor 120 by the monitoring current Ib, and compares the measured monitoring voltage Vb with the preset reference voltage Vr. Furthermore, the controller 130 monitors the normal or abnormal state of the solenoid coil 102 according to whether the monitoring voltage Vb is larger or smaller than the reference voltage Vr using the comparison result. Here, when the monitoring voltage Vb is measured by the controller 130, a noise signal may be included for various reasons. The monitoring voltage Vb measured by such a noise signal may have a certain deviation and its measurement range may vary. Therefore, in the present invention, if necessary, the preset reference voltage Vr has a fluctuation range that allows a constant deviation, and compares the fluctuation range of the monitored monitoring voltage Vb with the fluctuation range of the preset reference voltage Vr. When the fluctuation range of the monitoring voltage Vb is out of the fluctuation range of the reference voltage Vr, it is preferable to determine that the solenoid coil 102 is abnormal.

As described above, the change in the monitoring current Ib flowing through the resistor 120 connected in series with the constant current circuit 110 according to the change in the internal resistance value of the solenoid coil 102 is measured, and the monitoring current Ib is measured. ) Is converted into a voltage value and compared with the reference voltage to determine whether the solenoid coil 102 is abnormal.

Here, the constant current circuit 110 according to the present invention operates as an active load for controlling the monitoring current Ib. Therefore, when the control power supply Va becomes large, the internal resistance value increases. On the contrary, when the control power supply Va decreases, the internal resistance value decreases, so that a constant monitoring current Ib always flows. This is a key feature of the present invention which is critically different compared to the solenoid supervisory circuits presented in the prior art. In summary, since the solenoid monitoring circuit of the prior art is composed of three resistors (R1, R2, and R3 resistors in FIG. 1), the monitoring current Ib changes when the control power supply Va is changed. Therefore, it is unknown whether the change of the monitoring current Ib is due to the abnormal state of the solenoid coil or the change of the control power supply Va. Therefore, the solenoid monitoring circuit of the prior art must change the resistance of the first resistor R1 and the third resistor R3 so that the monitoring current Ib is kept constant whenever the control power supply Va is different. Otherwise, there is no choice but to apply a dedicated monitoring circuit for each solenoid coil. However, since the solenoid monitoring device of the present invention uses the constant current circuit 110, even when the control power supply Va is different as described above, the constant monitoring current Ib always flows so that the change in the monitoring current Ib is controlled. Only the change in the internal resistance value of the solenoid coil 102 is made, not the change in the power supply Va. Therefore, the problem of the prior art is solved so that the control power source can monitor different solenoid coils.

3 is an exemplary diagram of a constant current circuit according to an embodiment of the present invention.

Referring to FIG. 3, a constant current circuit according to an embodiment of the present invention includes a zener diode (ZD) and an NPN transistor (Q). More specifically, the first resistor (R1), diode (D), the control diode (ZD) is connected in series between the input power supply (V) and the ground, the connection point of the first resistor (R1) and diode (D) The NPN transistor Q is connected to the connection point, and the connection point is connected to the base of the NPN transistor Q, and the ground of the NPN transistor Q is connected through the input current In to the collector and the second resistor R2 to the emitter. Are respectively connected. Through this configuration, the output current is determined by the voltage Vzd applied to the zener diode ZD and the second resistor R2, and the output current has a constant value of Vzd / R2.

The constant current circuit shown in FIG. 3 is only one embodiment of the present invention, and it will be apparent to those skilled in the art that the constant current circuit may be implemented differently in other embodiments of the present invention. Therefore, in the present invention, a constant current circuit that can serve as an active element that allows a constant current to flow to any control power supply will be sufficient, and there will be no limitations on the element or circuit constituting the control power. For example, those skilled in the art may implement a constant current circuit using a regulator or using an OP amplifier and a transistor in another embodiment.

As described above, the solenoid coil monitoring apparatus using the constant current circuit according to the present invention is to connect a constant current circuit and a resistor in parallel to the solenoid coil and to use a constant current circuit so that a constant current always flows regardless of the magnitude of the control voltage. There is a characteristic. Due to this feature, the voltage across the resistor is caused only by the change in the internal resistance of the solenoid coil, thereby determining whether the solenoid coil is abnormal according to the change in the voltage across the resistor. This has the advantage that the control voltage can be applied irrespective of the type of the solenoid coils different from each other without changing or adding circuits.

Recently, as industrial facilities are enlarged, required power is increasing, and power consumption is increasing every year in homes and businesses. One of the essentials for the safe use of electricity in these power systems is the circuit breaker. A breaker is a machine that cuts off the current to prevent accidents when an overcurrent, ie, a current above the rated current flows in an electrical circuit. Used for the same purpose as a fuse, but once a fuse is replaced it must be replaced with a new one, but the breaker has the advantage that it can be used continuously.

This important breaker is typically controlled by the breaker opening and closing solenoid coil its opening and closing operation. If the solenoid coil malfunctions, if the power supply is cut off or excessive current is generated, serious damage to the equipment will occur, causing considerable human and physical damage. Therefore, it will be important to monitor whether the solenoid coil is abnormal in real time and take quick action.

In view of this aspect, the solenoid coil monitoring apparatus using the constant current circuit according to the present invention allows a constant current to flow by the constant current circuit irrespective of the magnitude of the input control voltage, so that only the solenoid coil is not changed in current. It detects the voltage change according to the resistance change of, so that the control power supply can be used to monitor different solenoid coils, which can be very useful for industrial field of power system.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments. Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope of the appended claims, The genius will be so self-evident. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

Claims (3)

In the solenoid coil monitoring device using a constant current circuit for monitoring the solenoid coil,
A constant current circuit configured to flow a constant monitoring current irrespective of a control power supply for supplying power to the solenoid coil;
A resistor configured to be connected in series with the constant current circuit; And
The monitoring voltage applied to both ends of the resistance is measured by the monitoring current flowing through the resistance, and the monitoring voltage measured according to the abnormality of the solenoid coil is compared with a preset reference voltage to determine whether the solenoid coil is abnormal. A control unit;
The constant current circuit is a solenoid coil sensing device using a constant current circuit, characterized in that to operate as an active load to maintain a constant magnitude of the monitoring current. The method according to claim 1, wherein the constant current circuit and the resistor,
Solenoid coil sensing device using a constant current circuit, characterized in that the monitoring current is set to flow so small that it does not drive the solenoid coil. The method according to claim 1, wherein the control unit,
And comparing the fluctuation range of the monitoring voltage with the preset fluctuation range of the reference voltage, and determining that the solenoid coil is abnormal when the fluctuation range of the monitoring voltage is out of the fluctuation range of the reference voltage. Solenoid coil detection device using a circuit.

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