CN211348584U - Leakage current tester - Google Patents
Leakage current tester Download PDFInfo
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- CN211348584U CN211348584U CN201922007495.1U CN201922007495U CN211348584U CN 211348584 U CN211348584 U CN 211348584U CN 201922007495 U CN201922007495 U CN 201922007495U CN 211348584 U CN211348584 U CN 211348584U
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Abstract
The utility model relates to the field of current test instruments, and discloses a leakage current tester, which comprises a current clamp, a signal amplifier, a frequency measuring unit, an AD converter, a phase measuring unit, a single chip microcomputer, a memory, a clock module, a touch screen, a USB interface, a wireless communication module and a power module, wherein the current clamp is respectively connected with the frequency measuring unit, the AD converter and the phase measuring unit through the signal amplifier, and the single chip microcomputer is also respectively connected with the memory, the clock module, the touch screen, the USB interface, the wireless communication module and the power module; the power module comprises a direct current boosting chip, a first diode, a first capacitor, a second diode, a first triode, a first resistor, a second triode, a third diode, a second capacitor, a rectifier bridge, a third capacitor and a first fuse. Implement the utility model discloses a leakage current tester has following beneficial effect: the safety and the reliability of the circuit are higher, and the requirement of safe power utilization is met.
Description
Technical Field
The utility model relates to a current test instrument field, in particular to leakage current tester.
Background
The leakage current is a current formed between metal parts electrically insulated from each other or between a charged part and a grounded part through a medium or an insulating surface around the charged part in the absence of a fault-applied voltage, and is referred to as a leakage current. According to the us UL standard, leakage current is a current that can be conducted from a household appliance accessible part, including a capacitive coupling current. The leakage current tester mainly comprises impedance conversion, range conversion, AC/DC conversion, amplification, indication devices and the like. Some of the devices also have overcurrent protection, an audible and visual alarm circuit and a test voltage adjusting device, and the indicating devices of the devices are analog and digital. In the conventional technology, some power supply parts of the leakage current tester lack corresponding circuit protection functions, such as: the lack of current-limiting protection causes the safety and reliability of the circuit to be lower, and the requirement of safe power utilization is not met.
SUMMERY OF THE UTILITY MODEL
The to-be-solved technical problem of the utility model lies in, to the above-mentioned defect of prior art, provide the leakage current tester that the security and the reliability of a circuit are higher, accord with the requirement of safe power consumption.
The utility model provides a technical scheme that its technical problem adopted is: the leakage current tester is constructed and comprises a current clamp, a signal amplifier, a frequency measuring unit, an AD converter, a phase measuring unit, a single chip microcomputer, a memory, a clock module, a touch screen, a USB interface, a wireless communication module and a power module, wherein the current clamp is respectively connected with the frequency measuring unit, the AD converter and the phase measuring unit through the signal amplifier;
the power supply module comprises a direct current boosting chip, a first diode, a first capacitor, a second diode, a first triode, a first resistor, a second triode, a third diode, a second capacitor, a rectifier bridge, a third capacitor and a first fuse, wherein one input end of the direct current boosting chip is connected with battery voltage, the other input end of the direct current boosting chip is connected with an auxiliary power supply, one output end of the direct current boosting chip is respectively connected with a voltage output end and an anode of the first diode, a cathode of the first diode is respectively connected with one end of the first capacitor and a cathode of the second diode, an anode of the second diode is respectively connected with an anode of the third diode, one end of the second capacitor and an anode direct current output end of the rectifier bridge, a base electrode of the first triode is respectively connected with one end of the first resistor and a collector electrode of the second triode, the collecting electrode of the first triode is respectively connected with the battery voltage and the other end of the first resistor, the base of the second triode is connected with the cathode of the third diode, another output end of the direct current boosting chip is respectively connected with the other end of the first capacitor, the emitting electrode of the first triode, the emitting electrode of the second triode, the other end of the second capacitor and the negative direct current output end of the rectifier bridge, an alternating current input end of the rectifier bridge is respectively connected with one end of the third capacitor and one end of the first fuse, another alternating current input end of the rectifier bridge is respectively connected with the other end of the third capacitor and the zero line, and the other end of the first fuse is connected with the live wire.
In the leakage current tester of the present invention, the model of the third diode is L-1822.
In the leakage current tester, the power module further includes a second resistor, one end of the second resistor is connected to the emitter of the first triode, and the other end of the second resistor is grounded.
In the leakage current tester of the present invention, the resistance of the second resistor is 29k Ω.
In the leakage current tester of the present invention, the first transistor is an NPN transistor.
In the leakage current tester of the present invention, the second triode is an NPN-type triode.
Implement the utility model discloses a leakage current tester has following beneficial effect: the current clamp, the signal amplifier, the frequency measuring unit, the AD converter, the phase measuring unit, the single chip microcomputer, the memory, the clock module, the touch screen, the USB interface, the wireless communication module and the power module are arranged; the power module includes direct current chip, first diode, first electric capacity, second diode, first triode, first resistance, second triode, third diode, second electric capacity, rectifier bridge, third electric capacity and first fuse that steps up, and the third diode is used for carrying out the current-limiting protection, consequently the utility model discloses the security and the reliability of circuit are higher, accord with the requirement of safe power consumption.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a schematic structural diagram of an embodiment of the leakage current tester of the present invention;
fig. 2 is a schematic circuit diagram of the power supply module in the embodiment.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
In the embodiment of the leakage current tester of the present invention, the schematic structural diagram of the leakage current tester is shown in fig. 1. In fig. 1, the leakage current tester includes a current clamp 1, a signal amplifier 2, a frequency measuring unit 3, an AD converter 4, a phase measuring unit 5, a single chip microcomputer 6, a memory 7, a clock module 8, a touch screen 9, a USB interface 10, a wireless communication module 11 and a power module 12, wherein the current clamp 1 is connected to the frequency measuring unit 3, the AD converter 4 and the phase measuring unit 5 through the signal amplifier 2, the frequency measuring unit 3, the AD converter 4 and the phase measuring unit 5 are also connected to the single chip microcomputer 6, and the single chip microcomputer 6 is also connected to the memory 7, the clock module 8, the touch screen 9, the USB interface 10, the wireless communication module 11 and the power module 12.
The current clamp 1 is clamped on a grounding copper bar of a transformer core to be tested, the current clamp 1 amplifies a current signal which is measured to leak through the transformer core of the copper bar and then transmits the current signal to a frequency measuring unit 3, the frequency measuring unit 3 compares a fundamental frequency according to the current signal measured by the current clamp 1 and judges whether the current signal is consistent with the fundamental frequency, the frequency characteristic of the grounding leakage current of the transformer core is judged and transmitted to a singlechip 6, the singlechip 6 draws a waveform characteristic diagram according to the actual measured frequency characteristic, the tested signal is transmitted to the signal amplifier 2 to be amplified, the signal is transmitted to an AD converter 4 after being amplified to a 0-5V voltage signal and converted into a digital signal which can be automatically identified by the singlechip 6, and the singlechip 6 collects the measured data and time signal information transmitted by a clock module 8.
The measured information quantities are simultaneously stored in the memory 7, the touch screen 9 can simultaneously display the measured information, the measured information can be read through the touch screen 9, and the measured data can also be stored in the mobile hard disk; the transformer core leakage current that current tong 1 measured sends phase place measuring unit 5 after signal amplifier 2, can judge that it leaks current and has which phase in A, B, C three phases to produce according to the phase place of its electric current automatically, the utility model discloses can judge the phase place automatically, analysis fault factor plays the positive role. The singlechip 6 stores the measured information including frequency, phase, current value, test time and the like in the memory 7, and the singlechip 6 can upload data to an upper computer through the wireless communication module 11.
In this embodiment, the signal amplifier 2 is of a model HJ417, the frequency measurement unit 3 is of a model CY8C29666, the AD converter 4 is of a model ADs12300IPW, the phase measurement unit 5 is of a model HJ4046, and the single chip microcomputer 6 is of a model MSP 430.
In this embodiment, the wireless communication module 11 is a bluetooth module, a WiFi module, a GSM module, a GPRS module, a CDMA2000 module, a WCDMA module, a TD-SCDMA module, a Zigbee module, or a LoRa module. Through setting up multiple wireless communication mode, not only can increase the flexibility of wireless communication mode, can also satisfy the demand of different users and different occasions. Especially, when adopting the loRa module, its communication distance is far away, and leads to the communication performance comparatively stable, is applicable to the occasion that requires the higher to communication quality.
In this embodiment, the current clamp 1, the signal amplifier 2, the frequency measuring unit 3, the AD converter 4, the phase measuring unit 5, the single chip microcomputer 6, the memory 7, the clock module 8, the touch screen 9, the USB interface 10, and the wireless communication module 11 are all implemented by using a structure in the prior art, and the working principle thereof is also the working principle in the prior art, which is not described here.
Fig. 2 is a schematic circuit diagram of a power module in this embodiment, in fig. 2, the power module 12 includes a dc boost chip U1, a first diode D1, a first capacitor C1, a second diode D2, a first transistor Q1, a first resistor R1, a second transistor Q2, a third diode D3, a second capacitor C2, a rectifier bridge Z, a third capacitor C3, and a first fuse F1, wherein one input terminal of the dc boost chip U1 is connected to a battery voltage Vi, another input terminal of the dc boost chip U1 is connected to an auxiliary power VCC, one output terminal of the dc boost chip U1 is connected to a voltage output terminal Vo and an anode of the first diode D1, a cathode of the first diode D1 is connected to one terminal of the first capacitor C1 and a cathode of the second diode D2, an anode of the second diode D2 is connected to an anode 3 of the third diode D, one terminal of the second capacitor C2 and an anode of the rectifier bridge Z, the base electrode of the first triode Q1 is connected with one end of a first resistor R1 and the collector electrode of a second triode Q2 respectively, the collector electrode of the first triode Q1 is connected with the battery voltage Vi and the other end of the first resistor R1 respectively, the base electrode of the second triode Q2 is connected with the cathode of a third diode D3, the other output end of the dc boost chip U1 is connected with the other end of a first capacitor C1, the emitter electrode of the first triode Q1, the emitter electrode of the second triode Q2, the other end of a second capacitor C2 and the negative dc output end of a rectifier bridge Z respectively, one ac input end of the rectifier bridge Z is connected with one end of a third capacitor C3 and one end of a first fuse F1 respectively, the other ac input end of the rectifier bridge Z is connected with the other end of the third capacitor C3 and a zero line N respectively, and the other end of the first fuse F1 is connected with a live line L.
In this embodiment, the third diode D3 is a current-limiting diode, and is used for current-limiting protection of the base current of the second transistor Q2. The current limiting protection principle is as follows: when the base current of second triode Q2 is great, can reduce the size of second triode Q2's base current through this third diode D3, make it keep at normal operating condition, and be unlikely to because of the too big components and parts that lead to burning out in the circuit of electric current, consequently the utility model discloses the security and the reliability of circuit are higher, accord with the requirement of safe power consumption. It should be noted that in the present embodiment, the model of the third diode D3 is L-1822. Of course, in practical applications, the third diode D3 may also be another type of diode with similar functions.
The working principle of the power module 12 is as follows: the battery voltage Vi is 12V, the voltage at the voltage output Vo is 220V, which is the output dc of the dc-dc booster circuit 1, and V + is the dc voltage output to the load (the single chip microcomputer 6). The dc boost chip U1 is a conventional dc 12 boost to dc 220V of various types of dc boost circuits, and the voltage output Vo generates an emergency output voltage V +1 on the first capacitor C1 through the first diode D1. The ac mains supply generates a dc voltage on the second capacitor C2 through the first fuse F1, the third capacitor C3 and the rectifier bridge Z, and generates a mains supply dc voltage V +2 on the first capacitor C1 through the second diode D2.
When the commercial power is available, the second capacitor C2 is charged, so that the second triode Q2 is turned on, the first triode Q1 is turned off, the auxiliary power source VCC is zero, the dc boost chip U1 does not operate, and the commercial power generates a dc voltage V +2 on the first capacitor C1 to supply the load. When the mains supply is powered off, the second capacitor C2 is not powered, so that the second triode Q2 is cut off, the first triode Q1 is switched on, the auxiliary power supply VCC is powered on, the direct current boost chip U1 works, and the voltage output end Vo generates emergency output voltage V +1 on the first capacitor C1 through the first diode D1 to supply power to the load. The first diode D1 and the second diode D2 play a role in isolating the emergency dc voltage from the dc voltage of the mains supply, and ensure that no perfusion occurs during the switching process. The capacitance of the first capacitor C1 is properly selected to store enough power to maintain the power supply during the switching process, and the first diode D1 and the second diode D2 are automatically turned on alternately to achieve zero switching time without a complicated timing control circuit.
In this embodiment, the first transistor Q1 is an NPN transistor, and the second transistor Q2 is an NPN transistor. Of course, in practical applications, the first transistor Q1 and the second transistor Q2 may be PNP transistors, but the circuit structure is changed accordingly.
In this embodiment, the power module 12 further includes a second resistor R2, one end of the second resistor R2 is connected to the emitter of the first transistor Q1, and the other end of the second resistor R2 is grounded. The second resistor R2 is a current limiting resistor, and is used for current limiting protection of the emitter current of the first transistor Q1. The current limiting protection principle is as follows: when the emitter current of the first triode Q1 is large, the second resistor R2 can reduce the emitter current of the first triode Q1 to keep the first triode Q1 in a normal working state, so that the elements in the circuit are not burnt out due to the large current, and the safety and reliability of the circuit are further enhanced. It should be noted that, in this embodiment, the resistance of the second resistor R2 is 29k Ω. Of course, in practical applications, the resistance of the second resistor R2 can be adjusted accordingly according to specific situations, that is, the resistance of the second resistor R2 can be increased or decreased accordingly according to specific situations.
In a word, in this embodiment, because the current-limiting diode is arranged in the power module 12, the circuit of the present invention has high safety and reliability, and meets the requirement of safe power utilization.
The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (7)
1. A leakage current tester is characterized by comprising a current clamp, a signal amplifier, a frequency measuring unit, an AD converter, a phase measuring unit, a single chip microcomputer, a storage, a clock module, a touch screen, a USB interface, a wireless communication module and a power module, wherein the current clamp is respectively connected with the frequency measuring unit, the AD converter and the phase measuring unit through the signal amplifier;
the power supply module comprises a direct current boosting chip, a first diode, a first capacitor, a second diode, a first triode, a first resistor, a second triode, a third diode, a second capacitor, a rectifier bridge, a third capacitor and a first fuse, wherein one input end of the direct current boosting chip is connected with battery voltage, the other input end of the direct current boosting chip is connected with an auxiliary power supply, one output end of the direct current boosting chip is respectively connected with a voltage output end and an anode of the first diode, a cathode of the first diode is respectively connected with one end of the first capacitor and a cathode of the second diode, an anode of the second diode is respectively connected with an anode of the third diode, one end of the second capacitor and an anode direct current output end of the rectifier bridge, a base electrode of the first triode is respectively connected with one end of the first resistor and a collector electrode of the second triode, the collecting electrode of the first triode is respectively connected with the battery voltage and the other end of the first resistor, the base of the second triode is connected with the cathode of the third diode, another output end of the direct current boosting chip is respectively connected with the other end of the first capacitor, the emitting electrode of the first triode, the emitting electrode of the second triode, the other end of the second capacitor and the negative direct current output end of the rectifier bridge, an alternating current input end of the rectifier bridge is respectively connected with one end of the third capacitor and one end of the first fuse, another alternating current input end of the rectifier bridge is respectively connected with the other end of the third capacitor and the zero line, and the other end of the first fuse is connected with the live wire.
2. The leakage current tester of claim 1, wherein the third diode is of type L-1822.
3. The leakage current tester of claim 1, wherein the power module further comprises a second resistor, one end of the second resistor is connected to the emitter of the first transistor, and the other end of the second resistor is grounded.
4. The leakage current tester of claim 3, wherein the second resistor has a resistance of 29k Ω.
5. The leakage current tester of any one of claims 1 to 4, wherein the first transistor is an NPN transistor.
6. The leakage current tester of any one of claims 1 to 4, wherein the second transistor is an NPN transistor.
7. The leakage current tester of claim 1, wherein the wireless communication module is a bluetooth module, a WiFi module, a GSM module, a GPRS module, a CDMA2000 module, a WCDMA module, a TD-SCDMA module, a Zigbee module, or a LoRa module.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201922007495.1U CN211348584U (en) | 2019-11-19 | 2019-11-19 | Leakage current tester |
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| CN201922007495.1U CN211348584U (en) | 2019-11-19 | 2019-11-19 | Leakage current tester |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112305458A (en) * | 2020-12-30 | 2021-02-02 | 南京斯泰恩智慧能源技术有限公司 | Wave recording type platform area residual current detection terminal and early warning system |
| CN115144790A (en) * | 2022-09-02 | 2022-10-04 | 山东理工大学 | High-voltage insulator leakage current online monitoring system and method |
-
2019
- 2019-11-19 CN CN201922007495.1U patent/CN211348584U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112305458A (en) * | 2020-12-30 | 2021-02-02 | 南京斯泰恩智慧能源技术有限公司 | Wave recording type platform area residual current detection terminal and early warning system |
| CN112305458B (en) * | 2020-12-30 | 2021-04-16 | 南京斯泰恩智慧能源技术有限公司 | Wave recording type platform area residual current detection terminal and early warning system |
| CN115144790A (en) * | 2022-09-02 | 2022-10-04 | 山东理工大学 | High-voltage insulator leakage current online monitoring system and method |
| CN115144790B (en) * | 2022-09-02 | 2022-11-18 | 山东理工大学 | High-voltage insulator leakage current online monitoring system and method |
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