KR20010086604A - Overload circuit interrupter in capable of electrical tripping and circuit breaker with that - Google Patents

Abstract

PURPOSE: The line circuit breaker is provided, in which has an overload circuit interrupter being capable of electronic trip for overload, not using bimetal as a trip device. CONSTITUTION: The overload circuit interrupter being capable of electronic trip, equipped on the hot line, comprises a trip part to interrupt operation of electric apparatus according to trip signal when overload occurs, a current changing volume detecting part(110) to transfer changing volume of load current on the line to voltage on the wiring system including signal part to sign occurrence of overload to the external, a rectifier part(122) to rectify voltage of the current changing volume detecting part(110), a level control part(124) to limit the rectified voltage at the rectifier part(122) to constant sized level, an integrating part(126) to charge supplied voltage from the level control part(124), a reference voltage generating part(134) to generate reference voltage, and a comparison part(136) to output trip signal for occurrence of overload when overload occurs comparing charged voltage at the integrating part(126) with reference voltage.

Description

OVERLOAD CIRCUIT INTERRUPTER IN CAPABLE OF ELECTRICAL TRIPPING AND CIRCUIT BREAKER WITH THAT}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power distribution system, and more particularly, to an overload circuit interrupter (OLCI) and a circuit breaker having the same, which prevent a malfunction by a dimmer and enable an electronic trip.

Switchboards in certain areas, such as urban, industrial or commercial areas, typically use low voltage networks of 600 volts or less. In particular, cables in the network are buried underground and are generally designed to flow in at more than one point. Such cables may cause defects due to various causes such as thermal degradation, aging, moisture, or damage by animals such as mice or squirrels. A circuit breaker is provided to protect the network from these causes. A disconnect device is required at both ends of the cable to isolate the faulty cable and to disconnect the cable, such as a fuse, to minimize the failure of the network. do. Cable disconnect devices are devices that can safely act on phase-to-phase faults, such as high voltage and low impedance faults.

Generally, wiring breakers and earth leakage breakers are used at home to prevent fire or electric shock. Wiring breakers are used for the purpose of protecting wires. First, if the current exceeds the rated value while using the load, the current flowing inside the breaker becomes higher than the normal current, and heat is generated, which causes the internal bimetal to be bent to bend the electric appliance. Block the operation. The second case is a short circuit between phases caused by a power tool or other metal object on the load side. In this case, since high current is generated instantaneously, the bimetal is heated to operate the magnet inside before the electric appliance is operated. , To block the operation of the electric appliance. Such a high current generates a lot of magnetic fields, and the magnet inside the electric appliance is operated accordingly. The circuit breaker has a function of protecting a user by detecting a circuit and cutting off a power supply when a user is shocked while using an electric device, as well as a function of the circuit breaker.

The bimetal used in the overload detection circuit provided in the circuit breaker to protect the electrical appliances from overheating and damage is made by rolling two kinds of metal plates with different thermal expansion coefficients by rolling method. Because it is different, it is curved according to the temperature. Since such bimetal is converted to a very large displacement even for a relatively small temperature change, it is widely used as a thermometer or a switch that automatically operates by detecting a temperature change, and is widely used in household electrical appliances. That is, the overload detection circuit cuts the circuit by using the property of bending toward the low-expansion material when an overcurrent flows to the electric circuit to increase the temperature of the metal plate.In the low-expansion material used for bimetal, an alloy having a very small thermal expansion is used. Nickel-chromium-iron alloys, nickel-manganese-iron alloys, or manganese-copper-nickel alloys are used as the expandable material. In particular, when using 120V, 15A or 20A AC power as a standard for overload protection circuit, if the current corresponding to 135% of the rated current flows, the circuit is cut off within 1 hour and corresponds to 200% of the rated current. When the current flows, the circuit can be cut off within 4 minutes.

However, in the conventional overload detection circuit using such a bimetal, since it is necessary to continuously detect the change state of the overcurrent for a predetermined time, for example, 4 minutes to 1 hour, it takes a lot of time and money to test the overload detection operation and the overload detection circuit. There is a problem. In addition, since the degree of curvature of the bimetal due to the overcurrent easily changes with the period of use of the overload protection circuit, the operating characteristics of the overload protection circuit tend to change over time. As a result, as time passes, the overload detection operation by the overload detection circuit becomes difficult to be performed properly. In addition, after the bimetal is bent by the overload detection and the circuit is cut off accordingly, the bent bimetal must be returned to its original position for the subsequent overload detection operation. It is true that there is a lot of economic and time loss for the continuous detection operation of the overload detection circuit.

In addition, in the case where a dimmer is provided, a conventional overload detection circuit often fails to discriminate between an overcurrent caused by a load of an electric circuit and a drive current caused by an operation of the dimmer.

The present invention has been made to solve the above problems, and an object thereof is to provide an overload detection circuit and a circuit breaker having the same, capable of electronic trip by overload, without using a bimetal for mechanical trip.

In addition, an object of the present invention is to provide an overload detection circuit and a circuit breaker having the same, which is capable of continuous overload detection operation and instantaneous circuit interruption, and reduces the time and cost required for testing the overload detection operation. .

In addition, an object of the present invention is to provide an overload detection circuit and a circuit breaker having the same that can prevent the malfunction caused by the operation of the dimmer by distinguishing the drive current and the overcurrent by the dimmer.

In addition, the present invention is an overload detection circuit and a circuit having the same can be automatically returned to the standby state by the electrical product is cut off according to the overload detection, and the overload detection circuit is displayed to the outside and the overload detection circuit is reset to the initial state. The purpose is to provide a breaker.

1 is a block diagram of a circuit breaker having an overload detection circuit according to a preferred embodiment of the present invention.

2 is an internal block diagram of an overload detection circuit according to a preferred embodiment of the present invention.

3 is a detailed circuit diagram of an overload detection circuit according to a preferred embodiment of the present invention.

4 is a block diagram of a display unit for providing a set signal and a reset signal in a circuit breaker having an overload detection circuit according to an exemplary embodiment of the present invention.

5A and 5B are diagrams showing voltage waveforms at the front and rear ends of the capacitor of the integrating unit, respectively, when no dimmer is used.

6A and 6B are diagrams showing voltage waveforms at the front and rear ends of the capacitor of the integrating unit, respectively, in the case of using a dimmer.

(Name of the code for the main part of the drawing)

100: overload detection unit 200: trip unit

300: display unit 110: current change amount detecting unit

120: overload determination unit 122: rectifier

124: level adjusting unit 126: integrating unit

130: trip signal generator 132: bias voltage generator

134: reference voltage generator 136: comparison unit

140: discharge control unit 310: display control unit

In order to achieve the above object, the electronic trip capable of overload detection circuit of the present invention is provided in the conductive line and the trip unit for blocking the operation of the electrical appliance according to the trip signal when the overload occurs, and the overload generation to the outside A wiring system comprising a display unit for displaying, the wiring system comprising: a current change amount detecting unit for converting a change amount of a load current flowing through a conductive line into a voltage, a rectifying unit rectifying a voltage of the current change amount detecting unit, and a voltage rectified by the rectifying unit A level controller for limiting the level to a size, an integrator for charging the voltage provided from the level controller, a reference voltage generator for generating a reference voltage, and an overload by comparing the voltage charged in the integrator with a reference voltage It may include a comparator for outputting a trip signal indicating the occurrence of overload at the time of occurrence.

The current variation detector may be a current converter CT.

The rectifier includes a first diode having a cathode terminal connected to one side of the current variation detector, an anode terminal grounded, an anode terminal grounded, and a cathode terminal connected to the other side of the current variation detector; A diode, a third diode having an anode terminal connected to the anode terminal of the first diode, an anode terminal connected to the cathode terminal of the second diode, and a cathode terminal connected to the cathode terminal of the third diode to adjust the level It may include a fourth diode leading to the negative.

The level control unit is a resistor connected between the output node of the rectifier and the ground, a first capacitor connected to the output node of the rectifier, and a power supply to the collector terminal, the voltage rectified through the first capacitor to the base terminal. And a transistor having a second capacitor connected between the emitter terminal and the ground, and a diode connected in parallel between the base terminal of the transistor and the ground.

The integrator includes a diode having an anode terminal connected to an emitter terminal of a level control transistor, a first resistor connected to a cathode terminal of the diode, at least one capacitor and a second connected in parallel between the first resistor and ground, respectively. The overload indication signal may be provided to the comparator through a node including a resistor, a third resistor and a fourth resistor connected in series between the first resistor and the ground, and through a node between the third resistor and the fourth resistor.

The reference voltage generator may include a variable resistor connected between a power supply and a ground, a variable resistor providing a reference voltage to a comparator through a control terminal, and a capacitor connected between a control terminal of the variable resistor and a ground.

The comparator may include an OP amplifier configured to receive an overload instruction signal of an integrator to a non-inverting input terminal and to receive a reference voltage to an inverting input terminal.

The electronic trip-enabled overload detection circuit may further include a discharge control unit configured to instantaneously discharge the voltage charged in the integrating unit after the wiring system is blocked due to the overload occurrence.

The discharge controller is configured to base the reset signal of the display unit through a first resistor connected to a capacitor of an integrator, an emitter terminal is grounded, a collector terminal is connected to the first resistor, and a second and third resistor and diode connected in series. A display unit connected in series to a first transistor provided as a terminal, an emitter terminal grounded, a collector transistor connected to a node between the second resistor and a third resistor, and a base terminal of the second transistor And a fourth resistor connected to the node between the fourth resistor and the fifth resistor and the ground to provide a set signal of the resistor; One of the nodes at both ends may be provided from the high potential node, and the set signal may be provided from the low potential node.

The electronic trip-enabled overload detection circuit may further include a bias voltage generator configured to provide a bias voltage to a non-inverting input terminal of the comparator in combination with an overload instruction signal of the integrator.

The bias voltage generator includes a first resistor and a second resistor connected in series between a power supply and a ground, an anode terminal is connected to a node between the first resistor and a second resistor, and a cathode terminal is provided at a non-inverting input terminal of a comparator. It may include a diode connected to, and a capacitor connected between the anode terminal of the diode and the ground.

In addition, the circuit breaker capable of electronic trip of the present invention is an overload detection unit connected to the conductive line to detect the occurrence of overload, a trip unit connected to the conductive line to block the operation of the circuit according to the trip signal of the overload detection unit; A display unit for displaying the occurrence of overload to the outside according to the trip signal of the overload detection unit, wherein the overload detection unit rectifies the current change amount detection unit for converting the change amount of the load current flowing through the conductive line into a voltage, and the voltage of the current change amount detection unit A rectifying unit, a level adjusting unit for limiting the voltage rectified by the rectifying unit to a level with a predetermined magnitude, an integrating unit charging a voltage provided from the level adjusting unit, a reference voltage generating unit generating a reference voltage, and the integrating unit Compare the voltage charged in the negative part with the reference voltage and That may include a comparison to output a trip signal.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a circuit breaker equipped with an overload detection circuit according to a preferred embodiment of the present invention.

Referring to FIG. 1, the circuit breaker of the present invention is provided in the phase conductive line HOT and the neutral conductive line NEU, and includes an overload detection unit 100 and an overload detection unit 100 for detecting an overcurrent caused by an overload in the conductive line. To the trip unit 200 and the overload output signal OLCI OUT to block the operation of the circuit breaker by cutting off the current flowing in the phase conductive line HOT and the neutral conductive line NEU according to the overload output signal OLCI OUT of the circuit. Accordingly, the display unit 300 for displaying the occurrence of overload to the outside. At this time, the circuit breaker of the present invention is provided with a set signal (OLCI SET) and a reset signal (OLCI RESET) of different levels to the overload detection unit 100 in accordance with the operation of the display unit 300, to provide an overload detection unit 100 Can be initialized.

Here, the phase conductive line HOT1 and the neutral conductive line NEU1 located at the front end of the trip unit 200, the phase conductive line HOT2 and the neutral conductive line NEU2 located at the rear end of the trip unit 200, and the overload Although the phase conductive line HOT3 and the neutral conductive line NEU3 positioned at the rear end of the detection unit 100 are shown with different symbols, all of the phase conductive lines (unless a short circuit or a special connection configuration is changed between these conductive lines). HOT) and a neutral conductive line (NEU). In addition, the neutral conductive line NEU may be connected to the ground terminal Ground in the overload detection circuit.

2 illustrates an internal block diagram of an overload detection circuit according to a preferred embodiment of the present invention.

Referring to FIG. 2, the overload detection circuit 100 of the present invention converts a change amount of a current flowing through the phase conductive line HOT into a voltage in the current change amount detection unit 110. The overload judging unit 120 determines whether an overload has occurred using the voltage provided through the current change amount detecting unit 110. The overload determination unit 120 rectifies the output voltage of the current change detection unit 110, the level control unit 124 for limiting the voltage rectified through the rectifier 122 to a predetermined level and whether or not an overload occurs In order to determine, it includes an integrating unit 126 that charges the voltage limited to a predetermined level to generate an overload indicative signal. The level adjusting unit 124 reduces the rectified voltage to a predetermined level so as to distinguish the current caused by the overload and the driving current by the dimmer. The trip signal generator 130 includes a comparator 136 comparing the overload indicative signal of the integrator 126 with a predetermined reference voltage, and the overload instruction signal is greater than the reference voltage. In a large case, the circuit breaker is tripped, and a trip signal OLCI OUT for generating an overload is generated through the display unit 300. Therefore, the trip signal generator 130 may include a bias voltage generator 132 for providing a bias voltage to the comparator 136 and a reference voltage generator 134 for providing a reference voltage.

At this time, when the circuit breaker trips due to an overload or an overload occurs on the display unit 300, the overload detection circuit 100 uses the set signal OLCI SET and the reset signal OLCI RESET. The discharge controller 140 may further include a discharge controller 140 capable of discharging the voltage charged in the electronic device 126.

3 is a detailed circuit diagram of an overload detection circuit according to a preferred embodiment of the present invention. Referring to Figure 3, the configuration and operation of the overload detection circuit of the present invention will be described.

The current change amount detector 110 may be a CT (Current Transformer) for detecting a change amount of the load current flowing through the phase conductive line and converting the change amount into a voltage.

The overload determining unit 120 generates the overload indicative signal by using the voltage provided through the current change amount detecting unit 110, and the rectifier 122, the level adjusting unit 124, and the integrating unit 126. It includes. The rectifier 122 may include a plurality of diodes D10, D11, D12, and D13 connected to the CT 110 to full-wave rectify the voltage. The anode terminal of the first diode D10 is grounded, and the cathode terminal is connected to one side of the CT 110. The anode terminal of the second diode D13 is grounded, and the cathode terminal is connected to the other side of the CT 110. The anode terminal of the third diode D11 is connected to the anode terminal of the first diode D10, the anode terminal of the fourth diode D12 is connected to the cathode terminal of the second diode D13, and the third and third The cathode terminals of the four diodes D11 and D12 are connected to each other. In the present invention, the full wave rectification using the plurality of diodes D10, D11, D12, and D13 has been described as an example, but half-wave rectification using one or two diodes may be possible.

The level control unit 124 is supplied with a power supply (+ 26V) to the resistor R9 and the collector terminal connected between the cathode terminals of the rectifier 122 diodes D11 and D12 and ground, and the base terminal is A Zener diode connected between the base of the transistor Q1 and the base terminal of the transistor Q1, which is connected to the resistor R9 through the capacitor C10, and the emitter terminal is connected to ground through the capacitor C11. (D14) may be included. In the present invention, the transistor Q1 is used as a bipolar junction transistor (BJT), but may be a field effect transistor (FET) such as a metal oxide semiconductor (MOS) transistor. The voltage applied to the level adjuster 124 is changed to a predetermined level through the resistor R9 and the capacitor C10, and the voltage of a predetermined level is integrated through the transistor Q1 serving as a buffer. Provided at 126. Zener diode (D14) is to limit the peak voltage due to a sudden change in the current generated during the operation of the electrical appliance, thereby protecting the overload detection circuit 100 and prevents malfunction due to instant charging of the integrating unit 126 Play a role.

Here, in order not to mistake the high peak driving current generated when using a dimmer as a current due to overload, the capacitor C10 limits the applied voltage to a constant level. In particular, since the drive current by an electric appliance such as a dimmer has a higher peak value than the current due to an overload, it is adjusted to the same level as the current due to the overload, and the use of the dimmer is determined by judging whether or not an overload occurs according to the adjusted level. Malfunctions can be prevented.

5A and 5B illustrate voltage waveforms at the first node N1 and the second node N2 corresponding to the front end and the rear end of the capacitor C10 when the dimmer is not used. 6A and 6B illustrate voltage waveforms of the first node N1 and the second node N2 of the capacitor C10 when the dimmer is used.

First, referring to FIGS. 5A and 5B, the voltage of the first node N1 applied to the capacitor C10 through the rectifier 122 appears between a minimum of 0 V and a maximum of 16.9 V and a peak-peak of 16.7 V. Peak to Peak) value. When the voltage of the first node N1 passes through the capacitor C10, the first node N1 appears between 5V and 20V, and has a peak-peak value of 14.7V. As such, when the dimmer is not used, a small width may increase due to the capacitor C10.

On the other hand, in the case of using the dimmer as shown in FIG. 6A, the voltage at the first node N1 has a peak-peak value of 28.6V from 20 V at the minimum to about 47.6 V at the maximum. However, a voltage having such a high peak value passes through the capacitor C10, and at the second node N2, a voltage between 4V and 19.6V is shown as shown in FIG. 6B, and a peak-peak value of 15.6V is shown. It can be seen that That is, when the dimmer is used, the voltage generated at the first node N1 is at a level and peak-peak value similar to that when the dimmer is not used at the second node N2 that has passed through the capacitor C10. You can see it appear. Therefore, the overload detection circuit of the present invention prevents malfunctions that may occur from the driving current caused by the dimmer, and can determine whether the overload occurs with a voltage having the same level and amplitude when the dimmer is used or not. .

The integrating unit 126 includes a plurality of capacitors C12 and C13 and resistors connected in parallel between the diode D15 and the resistor R10 connected in series to the emitter terminal of the transistor Q1 and the resistor R10 and the ground. R11) and a plurality of resistors R12 and R13 connected between resistor R11 and ground. The plurality of capacitors C12 and C13 charge the voltage applied through the transistor Q1, and compare the overload indicative signal when the voltage charged in the excitation C12 and C13 reaches a predetermined level. 136) to generate a trip signal (OLCI OUT) that may break the circuit. At this time, instead of using a plurality of capacitors for charging the voltage provided through the transistor Q1, only one may be used. The diode D15 prevents the voltage charged in the capacitors C12 and C13 from flowing backward through the transistor Q1, and the resistor R10 prevents the voltage from the capacitors C12 and C13 due to the instantaneous current change of the electrical appliance. This serves to block the charge. The resistor R11 connected in parallel with the capacitors C12 and C13 determines the time when the voltage is charged and discharged in the capacitors C12 and C13. The remaining resistors R12 and R13 limit current applied to the comparator 136 and lower input impedance to prevent malfunction of the comparator 136. When a voltage is charged in the capacitors C12 and C13, an overload indicative signal is provided to the trip signal generator 130 through the resistor R12.

The trip signal generation unit 130 receives the overload instruction signal from the overload determination unit 120 and compares the reference voltage with a reference voltage to determine whether the overload has occurred, the bias unit and the reference voltage for the comparison unit 136 and the comparison unit 136. It includes a bias voltage generator 132 and a reference voltage generator 134 to provide respectively. The comparator 136 may be configured as an operational amplifier. That is, the overload indicative signal of the integrating unit 126 is applied to the non-inverting input terminal (+) of the OP amplifier constituting the comparing unit 136. Accordingly, the OP amplifier 136 compares the reference voltage applied from the reference voltage generator 134 to the inverting input terminal (-) and the overload instruction signal to cut off the circuit when the overload instruction signal is greater than the reference voltage. Generate a trip signal (OLCI OUT).

At this time, the bias voltage generator 132 is connected to the non-inverting input terminal (+) of the OP amplifier 136 to apply a bias voltage. In the bias voltage generator 132, an anode terminal is connected to a node between the power supply (+ 26V) and the ground (R14, R15) and the node between the two resistors (R14, R15), and the OP amplifier 136 A diode D16 having a cathode terminal connected to the non-inverting input terminal (+) of the capacitor, and a capacitor C14 connected between the anode terminal of the diode D16 and ground. Resistors R14 and R15 distribute the power supply (+ 26V) to generate a bias voltage, and capacitor C14 is used for noise cancellation. The diode D16 is for blocking the voltage charged in the integrator 126 from flowing into the bias voltage generator 132. Accordingly, when no overload occurs, the capacitor C12 and C13 are not charged with a voltage higher than the bias voltage, so that the bias voltage of the bias voltage generator 132 is applied to the non-inverting input terminal (+) of the OP amplifier. On the other hand, when the circuit is overloaded and the voltage charged in the capacitors C12 and C13 is greater than or equal to the bias voltage, the voltage charged in the capacitors C12 and C13 is applied to the non-inverting input terminal (+) of the op amp so that the reference voltage Will be compared to

A reference voltage generated by the reference voltage generator 134 is applied to the inverting input terminal (−) of the OP amplifier 136 to be compared with an overload indicative signal generated by the integrator 126. The reference voltage generator 134 includes a variable resistor VR1 connected between a power supply (+ 26V) and ground, and a capacitor C15 connected between the variable resistor VR1 and ground, and is controlled by the variable resistor VR1. The reference voltage input terminal is connected to the inverting input terminal (-) of the OP amplifier 136. Therefore, the reference voltage applied to the inverting input terminal (−) of the OP amplifier 136 may be adjusted by adjusting the resistance value of the variable resistor VR1. As a result, when the voltage due to overload is detected in the electrical appliance, the capacitors C12 and C13 of the integrating unit 126 are charged, and when the overload instruction signal charged in the capacitors C12 and C13 is greater than the reference voltage, OP Through the output terminal of the amplifier 136, a trip signal OLCI OUT may be generated which may interrupt the circuit. The trip signal OLCI OUT is provided to the trip unit 200 to block the operation of the overloaded electrical product, and is provided to the display unit 300 to externally generate the overload through a light emitting device such as a light emitting diode (LED). I can display it.

On the other hand, in the conventional case of detecting the overload by using the bimetal curve, the operation of the overload detection circuit is stopped until the curved bimetal is returned after the bimetal is bent due to the detection of the overload and the circuit is cut off. Therefore, the continuous overload detection operation could not be properly performed accordingly. The overload detection circuit 100 of the present invention controls the trip of the electrical appliance by the voltage charged in the capacitors C12 and C13, and immediately after the circuit is blocked by the overload, the voltage charged in the capacitors C12 and C13 The discharge controller may further include a discharge controller 140 to enable continuous overload detection operation. Accordingly, the circuit C12 is controlled so that the operation of the circuit is controlled according to the charging of the capacitors C12 and C13, and the overload detection operation can be resumed immediately after the circuit is cut off, without the circuit being blocked by overload. By discharging the voltage charged in C13), overload detection and detection resume operation can be performed quickly. In addition, by reducing the test time required for the test process of the overload detection circuit, it is possible to save economic cost or time.

The discharge controller 140 may control the discharge of the capacitors C12 and C13 by using the set signal OLCI SET and the reset signal OLCI RESET across the resistor constituting the display unit 300.

4 is a block diagram illustrating a display unit 300 that provides a set signal and a reset signal in a circuit breaker having an overload detection circuit according to an exemplary embodiment of the present invention. Referring to FIG. 4, the display unit 300 may include a display control unit 310 for controlling the operation of the light emitting device to recognize the occurrence of overload from the outside. The display controller 310 may include a light emitting device such as an LED and a control circuit for controlling the on / off of the light emitting device in order to display the occurrence of overload to the outside. The display controller 310 may receive power through the resistor R300 connected to the phase conductive line HOT. That is, when an overload occurs and power is supplied to the display unit 300 to turn on the light emitting device, a voltage difference occurs across the resistor R300 so that the potential of the reset signal OLCI RESET is set to the set signal OLCI SET. Will be higher than the potential. On the other hand, when the overload is not detected and the light emitting device is not turned on, since the power is not applied to the display unit 300, the potentials of the reset signal OLCI RESET and the set signal OLCI SET will be the same.

Therefore, when a current flows through the resistor R300 of the display unit 300, the reset signal OLCI RESET maintains a high voltage and the set signal OLCI SET maintains a relatively low voltage. Accordingly, the reset signal OLCI RESET is applied to the base terminal of the first transistor Q2 through the resistors R19 and R18 and the diode D17 connected in series. The collector terminal of the second transistor Q3 is connected to a node between two resistors R19 and R18. The set signal OLCI SET is applied to the base terminal of the second transistor Q3 through series connected resistors R20 and R21, and another resistor R22 is connected to a node between the two resistors R20 and R21. Leads to grounding. The emitter terminals of the first and second transistors Q2 and Q3 both lead to ground.

Here, the resistance values R20, R21, and R22 are set to the extent that the second transistor Q3 is turned on by the set signal OLCI SET. In this case, when the overload is not detected and power is not applied to the display unit 300, the second transistor Q3 is turned on so that the voltage between the collector terminal and the emitter terminal is nearly zero. Accordingly, the first transistor Q2 is turned off so that the voltages are normally charged in the capacitors C12 and C13 of the integrator 136 to perform a normal overload detection operation. On the other hand, if an overload is detected through the overload detection circuit 100, a current flows in the display unit 300, and a voltage difference across the resistor will occur. Therefore, the set signal OLCI SET is maintained at a level at which the predetermined voltage is lower than that of the reset signal OLCI RESET, so that the second transistor Q3 will not be turned on. However, since the first transistor Q2 to which the reset signal OLCI RESET is applied is turned on, the voltage charged in the capacitors C12 and C13 of the integrating unit 126 is discharged through the first transistor Q2. Will be.

That is, when the circuit is cut off by overload detection and a signal indicating overload detection is displayed on the display unit 300, the voltage charged in the capacitors C12 and C13 of the integrating unit 126 is automatically transferred through the discharge control unit 140. Because of the discharge, the continuous overload detection operation is possible without a separate discharge process by the administrator.

As described above, according to the overload detection circuit of the present invention and the circuit breaker including the same, since the electronic trip is possible without requiring a mechanical trip device such as bimetal for the overload detection, more accurate and faster overload detection is possible. It is possible. This can reduce the time or cost of overload detection and testing.

In addition, the overload detection circuit of the present invention can prevent the malfunction of overload detection due to the use of a dimmer in advance.

In addition, the circuit breaker provided with the overload detection circuit of the present invention quickly discharges the overload detection circuit by discharging the voltage charged in the overload detection circuit simultaneously with the operation of the circuit breaker and the display unit when the circuit is interrupted by the overload detection. It can be initialized so that there is an advantage that continuous overload detection is possible.

In the above, a preferred embodiment of an overload detection circuit and a circuit breaker having the same according to the present invention have been described in detail, but the contents are not limited to the field of the present invention described in the following claims. In addition, in the art, it will be apparent to those skilled in the art that various changes or modifications are made within the scope of the present invention.

Claims (15)

In the wiring system provided in the conductive line and includes a trip unit for blocking the operation of the electrical appliance according to the trip signal when the overload occurs, and a display unit for displaying the overload generation to the outside, A current change amount detecting unit for converting a change amount of the load current flowing through the conductive line into a voltage; A rectifier for rectifying the voltage of the current change amount detector; A level adjusting unit limiting the voltage rectified by the rectifying unit to a level having a predetermined magnitude; An integrator for charging a voltage provided from the level controller; A reference voltage generator for generating a reference voltage; And A comparator for comparing a voltage charged in the integrator with a reference voltage and outputting a trip signal when an overload occurs Overload detection circuit capable of electronic trip including a. The method of claim 1, The current change amount detecting unit An overload detection circuit capable of electronic tripping as a current converter (CT). The method of claim 1, The rectifying unit A first diode having a cathode terminal connected to one side of the current variation detector and having an anode terminal grounded; A second diode having an anode terminal grounded and a cathode terminal connected to the other side of the current variation detector; A third diode having an anode terminal connected to the anode terminal of the first diode; And A fourth diode connected with an anode terminal to the cathode terminal of the second diode and a cathode terminal connected to the cathode terminal of the third diode leading to a level control Overload detection circuit capable of electronic trip including a. The method of claim 1, The level control unit A resistor connected between the output node of the rectifier and ground; A first capacitor connected to the output node of the rectifier; A transistor having power applied to a collector terminal, receiving a voltage rectified through the first capacitor as a base terminal, and a second capacitor connected between the emitter terminal and ground; And A diode connected in parallel between the transistor's base terminal and ground Overload detection circuit capable of electronic trip including a. The method of claim 1, The integral part A diode having an anode terminal connected to an emitter terminal of the level control transistor; A first resistor coupled to the cathode terminal of the diode; At least one capacitor and a second resistor connected in parallel between the first resistor and ground, respectively; And A third resistor and a fourth resistor connected in series between the first resistor and the ground; Including, And an electronic trip capable of providing an overload indication signal to a comparator through a node between the third and fourth resistors. The method of claim 1, The reference voltage generator A variable resistor connected between the power supply and the ground and providing a reference voltage to the comparator through a control terminal; And A capacitor connected between the control terminal of the variable resistor and a ground Overload detection circuit capable of electronic trip including a. The method of claim 1, The comparison unit OP amplifier to receive overload indication signal of integral part to non-inverting input terminal and reference voltage to inverting input terminal Overload detection circuit capable of electronic trip including a. The method of claim 1, Discharge control unit for discharging the voltage charged in the integrator momentarily after the wiring system is cut off due to overload Overload detection circuit capable of electronic trip further comprising a. The method of claim 8, The discharge control unit A first resistor connected to the capacitor of the integrator; A first transistor having an emitter terminal grounded, a collector terminal connected to the first resistor, and receiving a reset signal of a display unit through a second and third resistor and diode connected in series to a base terminal; A second transistor having an emitter terminal grounded and a collector terminal connected to a node between the second and third resistors; Fourth and fifth resistors connected in series to the base terminal of the second transistor to provide a set signal of a display unit; And A sixth resistor connected between the node between the fourth and fifth resistors and a ground; Including, And the reset signal is provided from a node having a high potential among the nodes across the resistor, and a set signal is provided from a node having a low potential. The method of claim 1, A bias voltage generator that provides a bias voltage to the non-inverting input of the comparator in combination with the overload indication signal of the integral Overload detection circuit capable of electronic trip further comprising a. The method of claim 10, The bias voltage generator A first resistor and a second resistor connected in series between the power supply and ground; A diode having an anode terminal connected to the node between the first resistor and the second resistor and a cathode terminal connected to the non-inverting input terminal of the comparator; And A capacitor connected between the anode terminal of the diode and ground Overload detection circuit capable of electronic trip including a. An overload detector connected to the conductive line to detect an overload occurrence; A trip unit connected to a conductive line to block operation of the circuit according to a trip signal of the overload detector; And A display unit for displaying the overload generation to the outside according to the trip signal of the overload detection unit Including but not limited to: The overload detection unit A current change amount detecting unit for converting a change amount of the load current flowing through the conductive line into a voltage; A rectifier for rectifying the voltage of the current change amount detector; A level adjusting unit limiting the voltage rectified by the rectifying unit to a level with a predetermined magnitude; An integrator for charging a voltage provided from the level controller, A reference voltage generator for generating a reference voltage, and A comparator for comparing a voltage charged in the integrator with a reference voltage and outputting a trip signal indicating an overload when an overload occurs An electronic trip circuit breaker comprising a. In the wiring system provided in the conductive line and includes a trip unit for blocking the operation of the electrical appliance according to the trip signal when the overload occurs, and a display unit for displaying the overload generation to the outside, A current change amount detecting unit for converting a change amount of the load current flowing through the conductive line into a voltage; An overload instruction signal generator for converting an output signal of the current variation detector into a voltage of a predetermined level and providing an overload instruction signal by charging the converted voltage; And A trip signal generator for generating a trip signal by comparing the overload instruction signal with a reference voltage. Overload detection circuit capable of electronic trip including a. The method of claim 13, The overload instruction signal generation unit A rectifier for rectifying the voltage of the current change amount detector; A level adjusting unit limiting the voltage rectified by the rectifying unit to a level with a predetermined magnitude; And Integrator for charging the voltage provided from the level control unit Overload detection circuit capable of electronic trip including a. The method of claim 13, The trip signal generator A reference voltage generator for generating a reference voltage; And A comparator for comparing a voltage charged in the integrator with a reference voltage and outputting a trip signal indicating an overload when an overload occurs Overload detection circuit capable of electronic trip including a.