CN214313087U - Circuit breaker - Google Patents

Abstract

A circuit breaker comprises a measuring circuit and at least one communicating electric loop, wherein two ends of the measuring circuit are connected with a first terminal and a second terminal of a contact mechanism, and the measuring circuit comprises a current sensor, a first voltage sensor, a second voltage sensor, a controller and an isolating circuit; the current sensor transmits a sensed current signal to the controller, the first voltage sensor transmits a sensed voltage of the first terminal to the controller, the second voltage sensor transmits a sensed voltage of the second terminal to the controller, the isolation circuit is used for enabling the measuring circuit not to form a current loop, and the controller obtains the impedance of the contact mechanism according to the current signal, the first voltage signal and the second voltage signal. The utility model discloses an at measuring circuit detection contact mechanism's impedance, isolating circuit makes and can not form the electric current return circuit among the measuring circuit, avoids forming electric leakage hidden danger.

Description

Circuit breaker

Technical Field

The utility model relates to a low-voltage apparatus, concretely relates to circuit breaker.

Background

The low-voltage circuit breaker is also called automatic air switch or automatic air circuit breaker, it is an electric apparatus which not only has the function of manual switch, but also can automatically implement voltage loss, undervoltage, overload and short-circuit protection. It can be used to distribute electric energy, start asynchronous motor infrequently, protect power supply circuit and motor, and automatically cut off circuit when they have serious overload or short circuit and undervoltage faults, and its function is equivalent to the combination of fuse switch and over-and-under-heat relay.

The contact mechanism is an important component of the low-voltage circuit breaker, and realizes the control of line electrification or power outage through switching on or switching off, but each switching on and switching off of the contact mechanism can cause the attenuation of the contact mechanism, so that the increase of circuit breaker path impedance further causes the increase of power consumption and the reduction of power transmission efficiency, and finally the low-voltage circuit breaker fails along with the continuous increase of the power consumption. At present, the on-resistance of the contact mechanism of the existing low-voltage circuit breaker cannot be measured in real time, the main reason is that the circuit of the measuring circuit and the circuit breaker cannot be isolated, a small circuit generated by the measuring circuit during working can flow through a load, the electric leakage risk is easily caused, and the potential safety hazard exists, so that the on-resistance of the contact mechanism cannot be measured in real time, and further the working state of the circuit breaker cannot be accurately detected and the service life of the circuit breaker cannot be predicted.

Disclosure of Invention

An object of the utility model is to overcome prior art's defect, provide a simple structure, can measure the circuit breaker of contact impedance.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

a circuit breaker comprises a measuring circuit and at least one communicating electric loop, wherein each communicating electric loop comprises a group of contact mechanisms for controlling the on-off of the electrified loop, two ends of the measuring circuit are respectively connected with a first terminal and a second terminal of each contact mechanism, and the measuring circuit comprises a current sensor, a first voltage sensor, a second voltage sensor, a controller and an isolating circuit;

the current sensor is connected to a first terminal of the contact mechanism, the first voltage sensor is connected to the first terminal of the contact mechanism, the current sensor transmits a current signal to the controller, the first voltage sensor transmits a first voltage signal to the controller, the second voltage sensor is connected to a second terminal of the contact mechanism and transmits a second voltage signal to the controller, the isolation circuit is connected with the controller and used for enabling the measuring circuit not to form a current loop, and the controller calculates impedance of the contact mechanism according to the obtained current signal, the obtained first voltage signal and the obtained second voltage signal.

Preferably, the isolation circuit is connected between the second voltage sensor and the controller, the second voltage sensor transmits the second voltage signal to the controller through the isolation circuit, and the current sensor and the first voltage sensor are respectively connected with the controller and directly transmit the current signal and the first voltage signal to the controller.

Preferably, the current sensor and the first voltage sensor are respectively connected with the isolation circuit, the current sensor and the first voltage sensor respectively transmit a current signal and a first voltage signal to the controller through the isolation circuit, and the second voltage sensor is connected with the controller and directly transmits a second voltage signal to the controller.

Preferably, the isolation circuit is further connected with an analog-to-digital conversion circuit, and the current sensor and the first voltage sensor are respectively connected with the isolation circuit through the analog-to-digital conversion circuit.

Preferably, the measuring circuit further comprises a controllable current source driven by the controller, the controllable current source is connected to each phase of the current loop, and the current of the current loop can be increased under the driving of the controller.

Preferably, the controllable current source includes a driving controller and a controllable circuit controlled by the driving controller, two ends of the controllable circuit are respectively connected to the second terminal and a zero line of the power-on loop, the controllable circuit includes a first conduction element, a resistor and a second conduction element which are connected in sequence, the first conduction element and the second conduction element are conducted under the driving of the driving controller, and the driving controller adjusts the current in the controllable circuit according to the voltage at two ends of the resistor.

Preferably, the measuring circuit further comprises one or more power supplies for supplying operating power to the measuring circuit.

Preferably, the current sensor is a hall current sensor, a transformer or a resistor, and the first voltage sensor and the second voltage sensor are one or a combination of more than one of the hall current sensor, the transformer or the resistor; the isolation circuit is composed of one or more isolation devices, and the controller is a single chip microcomputer.

Preferably, the measuring circuit further comprises two power supplies for supplying working power to the measuring circuit, wherein one power supply supplies power to the current sensor and the first voltage sensor, and the other power supply supplies power to the second voltage sensor.

Preferably, the measuring circuit comprises a current transformer, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a controller, a driving controller, a first field effect transistor, a second field effect transistor, an isolation circuit, an analog-to-digital conversion circuit, a first power supply and a second power supply;

the current transformer is used as a current sensor, a primary coil of the current transformer is connected in series with a first wiring end of the contact mechanism, a secondary coil of the current transformer is connected with an input end of the analog-to-digital conversion circuit, a first resistor and a second resistor are used as a first voltage sensor, one end of the first resistor is connected with one end of the primary coil of the current transformer, the other end of the first resistor is respectively connected with one end of the second resistor and the input end of the analog-to-digital conversion circuit, and the other end of the second resistor is connected with a zero line of the power-on loop; the output end of the analog-to-digital conversion circuit is connected with the input end of the isolation circuit, and the output end of the isolation circuit is connected with the input end of the controller; the third resistor and the fourth resistor are used as a second voltage sensor, one end of the third resistor is connected with a second wiring end of the contact mechanism, the other end of the third resistor is connected with one end of the fourth resistor and the input end of the controller, and the other end of the fourth resistor and one power supply end of the controller are connected with a zero line of the power-on loop;

the output end of the controller is connected with the input end of the driving controller, the G pole of the first field effect tube and the G pole of the second field effect tube are connected with the output end of the driving controller, the S pole of the first field effect tube and the S pole of the second field effect tube are respectively connected with two ends of a fifth resistor, the D pole of the first field effect tube is connected with the second wiring end of the contact mechanism, and the D pole of the second field effect tube is connected with a zero line of the power-on loop;

two power supply ends of the first power supply are respectively connected to the first wiring end and a zero line of the power-on loop, and an output end of the first power supply is connected with a power supply end of the analog-to-digital conversion circuit; two power supply ends of the second power supply are respectively connected to the second wiring end and a zero line of the power-on loop, and an output end of the second power supply is respectively connected with power supply ends of the drive controller and the controller.

The utility model discloses a circuit breaker can detect the impedance of contact mechanism in each looks circular telegram return circuit through measuring circuit, and isolating circuit among the measuring circuit makes measuring circuit can not form the electric current return circuit, avoids measuring circuit to produce the electric current of load of flowing through, forms the electric leakage hidden danger of circuit breaker.

In addition, the isolation circuit is connected with the controller, the first voltage sensor or the second voltage sensor transmits a voltage signal to the controller through the isolation circuit, so that the second voltage sensor is isolated from the first voltage sensor and the current sensor, and the measuring circuit cannot form a complete current loop.

In addition, the measuring circuit is also provided with a controllable current source, and controllable current is output under the driving of the controller so as to increase the current flowing through the contact mechanism and improve the measuring precision; in addition, the measuring circuit is also provided with a power supply for providing a working power supply.

Drawings

Fig. 1 is a schematic diagram of a circuit breaker of the present invention;

fig. 2 is a schematic diagram of a first embodiment of a circuit breaker according to the present invention;

fig. 3 is a schematic diagram of a second embodiment of a circuit breaker according to the present invention;

fig. 4 is a circuit diagram of a second embodiment of a circuit breaker according to the present invention;

fig. 5 is a schematic diagram of a third embodiment of the circuit breaker of the present invention (power supply source is omitted);

fig. 6 is a schematic diagram of a third embodiment of a circuit breaker according to the present invention;

fig. 7 is a waveform diagram (pulse type) of the current generated by the controllable current source and the current generated by the power-on loop in the circuit breaker of the present invention;

fig. 8 is a waveform diagram (continuous type) of the current generated by the controllable current source and the current generated by the power-on loop in the circuit breaker of the present invention.

Detailed Description

The following describes a specific embodiment of a circuit breaker according to the present invention with reference to the embodiments shown in fig. 1 to 8. The present invention is not limited to the description of the following embodiments.

A circuit breaker comprises a measuring circuit and at least one communicating electric loop, wherein each communicating electric loop comprises a group of contact mechanisms for controlling the on-off of the electrified loop, the measuring circuit is respectively connected with each communicating electric loop, two ends of the measuring circuit are respectively connected with a first terminal and a second terminal of the group of contact mechanisms, and the measuring circuit comprises a current sensor, a first voltage sensor, a second voltage sensor, a controller and an isolating circuit;

the current sensor is connected to a first terminal of the contact mechanism, the first voltage sensor is connected to the first terminal of the contact mechanism, the current sensor transmits a sensed current signal in an electrified loop to the controller, the first voltage sensor transmits a sensed voltage of the first terminal to the controller as a first voltage signal, the second voltage sensor is connected to a second terminal of the contact mechanism and transmits a sensed voltage of the second terminal to the controller as a second voltage signal, the isolation circuit is connected with the controller and used for enabling the measuring circuit not to form a current loop, and the controller calculates impedance of the contact mechanism according to the obtained current signal, the first voltage signal and the second voltage signal.

The utility model discloses a circuit breaker can detect the impedance of contact mechanism in each looks circular telegram return circuit through measuring circuit, and isolating circuit among the measuring circuit makes measuring circuit can not form the electric current return circuit, avoids measuring circuit to produce the electric current of load of flowing through, forms the electric leakage hidden danger of circuit breaker.

With reference to fig. 1-2, an embodiment of the first circuit breaker is provided, in this embodiment, the circuit breaker is a single-phase circuit breaker, a power circuit of the circuit breaker includes a live wire and a neutral wire, a contact mechanism of the power circuit is connected to the live wire, of course, a group of contact mechanisms may also be provided on the neutral wire, and in this embodiment, the contact mechanism connected to the live wire is marked as 1 in fig. 1; in the embodiment, the first terminal is a wire inlet end of the circuit breaker, which is marked as end a in the figure, the current sensor directly transmits a sensed current signal in an energized loop to the controller, the first voltage sensor is connected with the first terminal of the contact mechanism through the current sensor, two input ends of the first voltage sensor are respectively connected with a live wire and a zero wire, and the first voltage sensor directly transmits a sensed voltage of the first terminal (marked as V1 in the figures 1 and 2) to the controller as a first voltage signal; the second voltage sensor is connected to the second terminal of the contact mechanism, two input terminals of the second voltage sensor are respectively connected to the live wire and the zero wire, in this embodiment, the outlet terminal of the circuit breaker, which is labeled as the B terminal in the figure, the isolating circuit is connected between the second voltage sensor and the controller, the second voltage sensor transmits the sensed voltage (labeled as V2 in the figure) of the second terminal as a second voltage signal to the controller through the isolating circuit, the controller calculates the impedance of the contact mechanism according to the obtained current signal, the first voltage signal and the second voltage signal, specifically, the ratio of the difference between the first voltage signal and the second voltage signal to the current signal, and since the isolating circuit isolates the second voltage sensor from the controller, the first voltage sensor and the current sensor, the measuring circuit cannot form a complete current loop, therefore, the current flowing through the load can not be generated, and the electric leakage can be avoided.

Preferably, the measuring circuit further comprises a controllable current source driven by the controller, when the controller obtains a smaller current in the energized loop through the current transformer, the smaller current is not favorable for accurately measuring the impedance of the contact mechanism, the controller outputs the current by driving the controllable current source to increase the current in the energized loop, so that the requirement on the sensitivity of the current sensor can be reduced, and the measurement result is more accurate, the additional current generated by the controllable current source can be pulse-type (see fig. 7) or continuous-type (see fig. 8), and the controllable current source is connected to the second terminal of the contact mechanism, namely the outlet terminal or the load side of the circuit breaker.

Further, the measuring circuit further includes a power supply source for providing a working power supply for the measuring circuit, in fig. 2, the number of the power supply sources is two, one of the power supply sources supplies power to the current sensor and the first voltage sensor, the other supplies power to the second voltage sensor, any one of the two power supply sources can be used for supplying power to other elements such as the controller, in the figure, the first power supply source supplies power to the current sensor, the first voltage sensor and the controller, the second power supply source supplies power to the second voltage sensor, the isolation circuit and the controllable current source, and the two power supply sources can directly get power from the energized circuit, and certainly can also be a battery.

In this embodiment, the current sensor is a hall current sensor, a transformer or a resistor, and the first voltage sensor and the second voltage sensor are both one or a combination of more than one of the hall current sensor, the transformer or the resistor; the isolation circuit consists of one or more isolation devices, and the isolation devices can select an optical coupler or a transformer and the like; the controller has certain logic operation capability and storage function, and is preferably a single chip microcomputer.

In connection with fig. 3-4, an embodiment of a second circuit breaker is provided, which, like the first embodiment, is also a single-phase circuit breaker, the energizing circuit of which also comprises a live line and a neutral line, the contact mechanism being connected to the live line and also being labelled 1 in fig. 3 and 4; said current sensor being connected to a first terminal of the contact means, also denoted a-terminal in fig. 3, 4, a first voltage sensor being connected to the first terminal, one input of the first voltage sensor being connected to the live wire of the first terminal of the contact means via the current sensor, the other input being connected to the neutral wire of the energizing circuit, the current sensor, the first voltage sensors are respectively connected with the isolation circuits, the current sensors transmit sensed current signals (marked as I in figure 3) in the energized loop to the controller through the isolation circuits, the first voltage sensors transmit sensed voltage (marked as V1 in figure 3) of the first terminal to the controller through the isolation circuits as first voltage signals, two ends of the second voltage sensors are respectively connected with the second terminal and the controller, and the second sensors directly transmit sensed voltage (marked as V2 in figure 3) of the second terminal to the controller as second voltage signals. The controller calculates the impedance of the contact mechanism according to the obtained current signal, the first voltage signal and the second voltage signal, and the isolation circuit isolates the second voltage sensor and the controller from the first voltage sensor and the current sensor, so that a measurement circuit cannot form a complete current loop, current flowing through a load cannot be generated, and electric leakage is avoided.

In this embodiment, a controllable current source is preferably provided, which generates a controllable additional current driven by the controller, wherein the additional current may be a pulsed current or a continuous current, the controllable current source is activated when the controller detects a low current through the current sensor, and the controllable current source is provided at the second terminal of the contact mechanism. Therefore, when the current flowing in the electrifying loop is small, the controller drives the controllable current source to generate extra current, the requirement on the sensitivity of the current sensor is reduced in sequence, and the measurement precision is improved.

Specifically, the controllable current source comprises a driving controller and a controllable circuit controlled by the driving controller, two ends of the controllable circuit are respectively connected to the second terminal of the contact mechanism and a zero line of the power-on loop, the controllable circuit comprises a first conduction element, a resistor and a second conduction element which are sequentially connected, the first conduction element and the second conduction element are conducted under the driving of the driving controller to enable current to flow in the controllable circuit, and the driving controller adjusts the current in the controllable circuit according to the voltage at two ends of the resistor.

Preferably, the measuring circuit further comprises an analog-to-digital conversion circuit, the current sensor and the first voltage sensor are respectively connected with the isolation circuit through the analog-to-digital conversion circuit, the analog-to-digital conversion circuit converts a voltage signal transmitted by the current sensor into a digital signal, and then the isolation circuit transmits a current value to the controller; the first voltage sensor converts the obtained voltage into a small signal and transmits the small signal to the analog-to-digital conversion circuit, and the voltage value is transmitted to the controller by the isolation circuit after the small signal is converted into a digital signal by the analog-to-digital conversion circuit.

Furthermore, the measuring circuit further comprises one or more power supplies for providing a working power supply for the measuring circuit, in this embodiment, two power supplies are also provided, the first power supply is used for supplying power to the current sensor, the first voltage sensor, the analog-to-digital conversion circuit and the isolation circuit, and the second power supply is used for supplying power to the second voltage sensor, the controller and the driving controller in the controllable current source.

In this embodiment, the current sensor is a hall current sensor, a transformer or a resistor, and the first voltage sensor and the second voltage sensor are both one or a combination of more than one of the hall current sensor, the transformer or the resistor; the isolation circuit consists of one or more isolation devices, and the isolation devices can select an optical coupler or a transformer and the like; the controller has certain logic operation capacity and a storage function, and is preferably a single chip microcomputer; the analog-to-digital conversion circuit can be a circuit comprising an analog-to-digital conversion chip, such as a circuit formed by an ADC0809CCVX, the driving controller can be a circuit comprising a chip, such as a circuit formed by a HEF4011 chip, and the first conducting element and the second conducting element are preferably field effect transistors.

With reference to fig. 4, a connection manner of the measurement circuit in this embodiment is provided, where the measurement circuit includes a current transformer T1, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a controller, a driving controller, a first fet M1, a second fet M2, an isolation circuit, an analog-to-digital conversion circuit, a first power supply, and a second power supply;

the current transformer T1 is used as a current sensor, the primary coil of the current transformer T1 is connected in series to the first terminal of the contact mechanism, the secondary coil of the current transformer T1 is connected to the input terminal of the analog-to-digital conversion circuit, the first resistor R1 and the second resistor R2 are used as a first voltage sensor, one end of the first resistor R1 is connected to one end of the primary coil of the current transformer T1, so that the first resistor R1 is connected to the first terminal of the contact mechanism through the primary coil (in practical application, the primary coil of the current transformer is a live wire, the impedance of the live wire is negligible, or one end of the first resistor R1 can be directly connected to the first terminal of the contact mechanism), the other end of the first resistor R1 is connected to one end of the second resistor R2, the input end of the analog-to-digital conversion circuit is connected, and the other end of the second resistor R2 is connected to the zero line of the power-on loop; the output end of the analog-to-digital conversion circuit is connected with the input end of the isolation circuit, and the output end of the isolation circuit is connected with the input end of the controller; the third resistor R3 and the fourth resistor R4 are used as a second voltage sensor, one end of the third resistor R3 is connected with the second terminal of the contact mechanism, the other end of the third resistor R3 is connected with one end of the fourth resistor R4 and the input end of the controller, and the other end of the fourth resistor R4 and one power supply end of the controller are connected with the zero line of the power-on loop;

the output end of the controller is connected with the input end of the driving controller, the G pole of the first field-effect tube M1 and the G pole of the second field-effect tube M2 are connected with the output end of the driving controller, the S pole of the first field-effect tube M1 and the S pole of the second field-effect tube M2 are respectively connected with two ends of a fifth resistor R5, the D pole of the first field-effect tube M1 is connected with the second terminal of the contact mechanism, and the D pole of the second field-effect tube M2 is connected with the zero line of the power-on loop;

two power supply ends of the first power supply are respectively connected to the first wiring end and a zero line of the power-on loop, and an output end of the first power supply is connected with a power supply end of the analog-to-digital conversion circuit; two power supply ends of the second power supply are respectively connected to the second wiring end and a zero line of the power-on loop, and an output end of the second power supply is respectively connected with power supply ends of the driving controller and the controller.

The working principle is as follows: when the contact mechanism is switched on, current flows through a primary coil of the current transformer T1, a secondary coil of the current transformer T1 generates corresponding voltage, the current is converted into a digital signal through analog-to-digital conversion, and the current value is transmitted to the controller through the isolation circuit by the isolation circuit; the voltage V1 between the live wire and the zero wire of the first terminal is converted into a small signal as a first voltage by the first resistor R1 and the second resistor R2, the small signal is transmitted to the analog-digital conversion circuit, and the small signal is converted into a digital signal by the analog-digital conversion circuit and transmitted to the controller through the isolation circuit; the third resistor R3 and the fourth resistor R4 convert the voltage V2 between the live wire and the zero wire of the second terminal of the contact mechanism into a small signal serving as a second voltage and transmit the small signal to the controller, and the controller calculates the impedance value of the contact mechanism according to the current signal, the first voltage and the second voltage.

When the current transformer T1 detects that the current is flowing, the controllable current source is activated, the controller outputs a high voltage to turn on the first fet M1 and the second fet M2 under the driving of the controller, the current flows through the controllable circuit composed of the first fet M1, the fifth resistor R5 and the second fet M2, a corresponding voltage is generated across the fifth resistor R5, and the controller adjusts the current that is turned on by the first fet M1 and the second fet M2 according to the voltage across the fifth resistor R5, so as to control the flowing current.

A third circuit breaker embodiment is provided in conjunction with fig. 5-6, in this embodiment, the circuit breaker is a three-phase four-wire circuit breaker, and includes a three-phase energizing loop having an a-phase live wire, a B-phase live wire, and a C-phase live wire, respectively, with a set of contact mechanisms connected to each phase live wire. In the embodiment, a current sensor is connected to the first terminal of each phase contact mechanism, the first voltage sensor is connected to the first terminals of the three groups of contact mechanisms through three current sensors, the three current sensors are connected with the controller respectively and used for transmitting current signals to the controller, wherein the current of the A phase circuit is IA, the current of the B phase circuit is IB, and the current of the C phase circuit is IC; the first voltage sensor respectively transmits the voltages of the first terminals of the three groups of contact mechanisms to the controller, and a first voltage signal of a three-phase electrified loop is represented by V1A, V1B and V1C respectively; a second voltage sensor is connected to the second terminals of the three sets of contact mechanisms and communicates a second voltage signal of the three-phase energizing circuit to the controller via the isolation circuit, as represented by V2A, V2B, and V2C, respectively.

Preferably, the current source further comprises three controllable current sources, the controllable current sources are respectively connected to a phase-to-phase circuit, and the controller can drive each phase-to-phase circuit to generate additional current. Further, as in the first embodiment and the second embodiment, the present embodiment further includes two power supplies for supplying a working power to the measurement circuit.

When the contact mechanism is switched on, the controller obtains the current I flowing through the contact mechanism through the current sensor, the controller obtains the first voltage V1 of the first terminal and the second voltage V2 of the second terminal of the contact mechanism through the first voltage sensor and the second voltage sensor respectively, and the controller calculates and stores the impedance value of the contact mechanism according to the impedance Z of the contact mechanism, namely (V1-V2)/I.

Further, the controller obtains the impedance change of the contact mechanism by comparing the impedance values of the contact mechanism in the nth closing and the n-1 closing, and accordingly judges the working condition of the contact mechanism and predicts the service life of the contact mechanism; wherein n is an integer of 1 or more.

The foregoing is a more detailed description of the present invention, taken in conjunction with the specific preferred embodiments thereof, and it is not intended that the invention be limited to the specific embodiments shown and described. To the utility model belongs to the technical field of ordinary technical personnel, do not deviate from the utility model discloses under the prerequisite of design, can also make a plurality of simple deductions or replacement, all should regard as belonging to the utility model discloses a protection scope.

Claims (8)

1. A circuit breaker, characterized by: the device comprises a measuring circuit and at least one communicating electric loop, wherein each communicating electric loop comprises a group of contact mechanisms for controlling the on-off of the communicating electric loop, two ends of the measuring circuit are respectively connected with a first terminal and a second terminal of each contact mechanism, and the measuring circuit comprises a current sensor, a first voltage sensor, a second voltage sensor, a controller and an isolating circuit;

the current sensor is connected to a first terminal of the contact mechanism, the first voltage sensor is connected to the first terminal of the contact mechanism, the current sensor transmits a current signal to the controller, the first voltage sensor transmits a first voltage signal to the controller, the second voltage sensor is connected to a second terminal of the contact mechanism and transmits a second voltage signal to the controller, the isolation circuit is connected with the controller and used for enabling the measuring circuit not to form a current loop, and the controller calculates impedance of the contact mechanism according to the obtained current signal, the obtained first voltage signal and the obtained second voltage signal.

2. A circuit breaker according to claim 1, wherein: the isolation circuit is connected between the second voltage sensor and the controller, the second voltage sensor transmits a second voltage signal to the controller through the isolation circuit, and the current sensor and the first voltage sensor are respectively connected with the controller and directly transmit the current signal and the first voltage signal to the controller; or the current sensor and the first voltage sensor are respectively connected with the isolation circuit, the current sensor and the first voltage sensor respectively transmit a current signal and a first voltage signal to the controller through the isolation circuit, and the second voltage sensor is connected with the controller and directly transmits a second voltage signal to the controller.

3. A circuit breaker according to claim 2, wherein: the isolation circuit is further connected with an analog-to-digital conversion circuit, and the current sensor and the first voltage sensor are respectively connected with the isolation circuit through the analog-to-digital conversion circuit.

4. A circuit breaker according to any one of claims 1-3, wherein: the measuring circuit also comprises a controllable current source driven by the controller, the controllable current source is connected in each phase of the electric loop, and the current of the electric loop can be increased under the driving of the controller.

5. A circuit breaker according to claim 4, wherein: the controllable current source comprises a driving controller and a controllable circuit controlled by the driving controller, two ends of the controllable circuit are respectively connected to the second terminal and a zero line of the power-on loop, the controllable circuit comprises a first conduction element, a resistor and a second conduction element which are sequentially connected, the first conduction element and the second conduction element are conducted under the driving of the driving controller, and the driving controller adjusts the current in the controllable circuit according to the voltage at two ends of the resistor.

6. A circuit breaker according to claim 4, wherein: the measuring circuit also comprises one or more power supply sources for providing working power supply for the measuring circuit; the current sensor is a Hall current sensor, a transformer or a resistor, and the first voltage sensor and the second voltage sensor are one or more of the combination of the Hall current sensor, the transformer or the resistor; the isolation circuit is composed of one or more isolation devices, and the controller is a single chip microcomputer.

7. A circuit breaker according to claim 4, wherein: the measuring circuit further comprises two power supplies for providing a working power supply for the measuring circuit, wherein one power supply supplies power for the current sensor and the first voltage sensor, and the other power supply supplies power for the second voltage sensor.

8. A circuit breaker according to claim 1, wherein: the measuring circuit comprises a current transformer, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a controller, a driving controller, a first field effect transistor, a second field effect transistor, an isolating circuit, an analog-to-digital conversion circuit, a first power supply and a second power supply;

the current transformer is used as a current sensor, a primary coil of the current transformer is connected in series with a first wiring end of the contact mechanism, a secondary coil of the current transformer is connected with an input end of the analog-to-digital conversion circuit, a first resistor and a second resistor are used as a first voltage sensor, one end of the first resistor is connected with one end of the primary coil of the current transformer, the other end of the first resistor is respectively connected with one end of the second resistor and the input end of the analog-to-digital conversion circuit, and the other end of the second resistor is connected with a zero line of the power-on loop; the output end of the analog-to-digital conversion circuit is connected with the input end of the isolation circuit, and the output end of the isolation circuit is connected with the input end of the controller; the third resistor and the fourth resistor are used as a second voltage sensor, one end of the third resistor is connected with a second wiring end of the contact mechanism, the other end of the third resistor is connected with one end of the fourth resistor and the input end of the controller, and the other end of the fourth resistor and one power supply end of the controller are connected with a zero line of the power-on loop;

the output end of the controller is connected with the input end of the driving controller, the G pole of the first field effect tube and the G pole of the second field effect tube are connected with the output end of the driving controller, the S pole of the first field effect tube and the S pole of the second field effect tube are respectively connected with two ends of a fifth resistor, the D pole of the first field effect tube is connected with the second wiring end of the contact mechanism, and the D pole of the second field effect tube is connected with a zero line of the power-on loop;

two power supply ends of the first power supply are respectively connected to the first wiring end and a zero line of the power-on loop, and an output end of the first power supply is connected with a power supply end of the analog-to-digital conversion circuit; two power supply ends of the second power supply are respectively connected to the second wiring end and a zero line of the power-on loop, and an output end of the second power supply is respectively connected with power supply ends of the drive controller and the controller.

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