CN220086952U - Protection circuit of passive leakage current tester input test power supply - Google Patents
Protection circuit of passive leakage current tester input test power supply Download PDFInfo
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- CN220086952U CN220086952U CN202321658992.8U CN202321658992U CN220086952U CN 220086952 U CN220086952 U CN 220086952U CN 202321658992 U CN202321658992 U CN 202321658992U CN 220086952 U CN220086952 U CN 220086952U
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- 238000012360 testing method Methods 0.000 title claims abstract description 29
- 238000001514 detection method Methods 0.000 claims abstract description 30
- 238000002955 isolation Methods 0.000 claims abstract description 15
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
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Abstract
The utility model discloses a protection circuit of a passive leakage current tester input test power supply, which comprises: the device comprises a relay K1, a relay K2, voltage dividers (R1 and R2), an operational amplifier, a precision rectifying circuit, a low-pass filter and a detection ARM; the relay K1 is used for switching an input power supply, and when the input power supply of the isolation transformer is detected, the relay K1 is attracted, and the input power supply is connected to the test circuit; the relay K2 is a change-over switch for switching the N, L phase power supply. According to the utility model, when the input power supply is judged to be the mains voltage, the detection ARM of the protection circuit sends the signal into the main control ARM for alarming, if the signal is the voltage input by the isolation transformer, the detected L, N phase voltage is zero, the main control ARM does not alarm, the test can be carried out, and the relay K1 is attracted, so that the judgment and the protection of the input power supply voltage are realized.
Description
Technical Field
The utility model relates to the technical field of electronic circuits, in particular to a protection circuit for an input test power supply of a passive leakage current tester.
Background
The leakage current tester is divided into an active leakage current tester and a passive leakage current tester, and a test power supply of the active leakage current tester is arranged in the test and does not need external connection, so that the problem of burning out test due to the access of an external power supply is solved;
however, the passive leakage current tester needs to be externally connected with a test power supply to test, and the externally connected power supply needs to be an isolated power supply isolated from the mains supply; however, operators often carelessly connect commercial power into the tester due to misoperation, so that the tester is damaged.
Disclosure of Invention
This section is intended to outline some aspects of embodiments of the utility model and to briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section as well as in the description of the utility model and in the title of the utility model, which may not be used to limit the scope of the utility model.
The present utility model has been made in view of the above-described problems occurring in the operation of the conventional passive leakage current tester.
In order to solve the technical problems, the utility model provides the following technical scheme:
a protection circuit for a passive leakage current tester input test power supply, comprising: the device comprises a relay K1, a relay K2, voltage dividers (R1 and R2), an operational amplifier, a precision rectifying circuit, a low-pass filter and a detection ARM;
the relay K1 is used for switching an input power supply, and when the input power supply of the isolation transformer is detected, the relay K1 is attracted, and the input power supply is connected to the test circuit;
the relay K2 is a change-over switch for switching and measuring N, L phase power supply;
the voltage divider (R1, R2) is used for converting 220V voltage into 2.2V voltage which can be measured;
the precise rectification circuit is used for converting alternating voltage into alternating direct voltage;
the low-pass filter circuit is used for converting alternating direct-current voltage into stable direct-current voltage;
the detection ARM converts the analog voltage into digital quantity for judgment.
As a preferable scheme of the protection circuit of the passive leakage current tester input test power supply, the utility model comprises the following steps: the protection circuit further includes: the main control ARM is used for controlling the relay K1 and alarming a detection signal for detecting the ARM.
As a preferable scheme of the protection circuit of the passive leakage current tester input test power supply, the utility model comprises the following steps: the protection circuit further includes: and the isolation circuit is used for isolating signals of the main control ARM and the detection ARM.
As a preferable scheme of the protection circuit of the passive leakage current tester input test power supply, the utility model comprises the following steps: after the ARM detection is judged to be finished, the result is transmitted to the main control ARM through the USART interface by isolating current.
As a preferable scheme of the protection circuit of the passive leakage current tester input test power supply, the utility model comprises the following steps: the 2.2V detection voltage is changed into the alternating-current direct-current voltage 2.2V after passing through the operational amplifier and the precise rectification circuit, and the voltage is changed into the stable direct-current voltage after passing through the low-pass filter and then is sent into the detection ARM.
The utility model has the beneficial effects that: according to the utility model, when the input power supply is judged to be the mains voltage, the detection ARM of the protection circuit sends the signal into the main control ARM for alarming, if the signal is the voltage input by the isolation transformer, the detected L, N phase voltage is zero, the main control ARM does not alarm, the test can be carried out, and the relay K1 is attracted, so that the input power supply voltage is judged and protected, and the protection circuit is simple and easy to realize and popularize.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present utility model, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art. Wherein:
fig. 1 is a diagram of a protection circuit for an input test power supply of a passive leakage current tester according to the present utility model.
Detailed Description
In order that the above-recited objects, features and advantages of the present utility model will become more readily apparent, a more particular description of the utility model will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present utility model, but the present utility model may be practiced in other ways other than those described herein, and persons skilled in the art will readily appreciate that the present utility model is not limited to the specific embodiments disclosed below.
Further, reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic can be included in at least one implementation of the utility model. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.
Further, in describing the embodiments of the present utility model in detail, the cross-sectional view of the device structure is not partially enlarged to a general scale for convenience of description, and the schematic is only an example, which should not limit the scope of protection of the present utility model. In addition, the three-dimensional dimensions of length, width and depth should be included in actual fabrication.
Referring to fig. 1, for one embodiment of the present utility model, a protection circuit for a passive leakage current tester input test power supply is provided, the protection circuit comprising: the circuit comprises a relay K1, a relay K2, voltage dividers (R1 and R2), an operational amplifier, a precision rectifying circuit, a low-pass filter, a detection ARM, a main control ARM and an isolation circuit.
The relay K1 is used for switching an input power supply, and when the input power supply of the isolation transformer is detected, the relay K1 is attracted, and the input power supply is connected to the test circuit; the relay K2 is a change-over switch for switching the N, L phase power supply; the voltage divider (R1, R2) is used for converting the 220V voltage into a measurable 2.2V voltage; the precise rectification circuit is used for converting alternating voltage into alternating direct voltage; the low-pass filter circuit is used for converting alternating direct-current voltage into stable direct-current voltage; the detection ARM converts the analog voltage into digital quantity to judge, the main control ARM is used for controlling the relay K1, meanwhile, the detection signal of the detection ARM is alarmed, the isolation circuit realizes the signal isolation of the main control ARM and the detection ARM, and after the judgment of the detection ARM is finished, a result is transmitted to the main control ARM through an USART interface through an isolation current.
Further describing the protection circuit, when starting detection, the relay K2 is switched to the L phase, if the input is the mains supply, 220V voltage difference exists between the L phase and the ground, and the 220V voltage difference is converted into 2.2V voltage required by the signal processing circuit through the voltage divider (R1, R2); the voltage is changed into alternating-current direct-current voltage 2.2V after passing through an operational amplifier and a precise rectifying circuit, the voltage is changed into stable direct-current voltage after passing through a low-pass filter and then is sent into a detection ARM, the ARM judges that the voltage is 220V, the input power supply is the commercial power, an alarm signal is transmitted to a main control ARM through an isolating circuit, and the main control ARM alarms.
When the input power supply is the power supply of the isolation transformer, the relay K2 is firstly switched to the L phase, the voltage difference of the power supply is converted into the voltage required by the signal processing circuit through the voltage divider (R1, R2), the voltage is changed into the alternating current direct current voltage after passing through the operation amplifier and the precise rectification circuit, the voltage is changed into the stable direct current voltage after passing through the low-pass filter and then is sent into the detection ARM, and if the detection ARM judges that the voltage is zero, the detection of the N phase is performed. The relay K2 is firstly switched to N phases, the voltage difference of the power supply is converted into voltage required by the signal processing circuit through the voltage divider (R1, R2), the voltage is changed into alternating-current direct-current voltage after passing through the operational amplifier and the precise rectifying circuit, the voltage is changed into stable direct-current voltage after passing through the low-pass filter and then is sent into the detection ARM, and if the detection ARM judges that the voltage is zero, the voltage difference between the input power supply of L, N phases and the ground is zero. At the moment, the input power is the input power of the isolation transformer, the main control ARM controls the relay K1 to be attracted, and the passive leakage current tester can start testing.
In summary, the utility model accurately judges the input power supply, can give an alarm in time when the input power supply is connected in error, and the main control ARM does not give an alarm when the input voltage of the isolation transformer is connected correctly, so that the utility model can carry out test.
It should be noted that the above embodiments are only for illustrating the technical solution of the present utility model and not for limiting the same, and although the present utility model has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present utility model may be modified or substituted without departing from the spirit and scope of the technical solution of the present utility model, which is intended to be covered in the scope of the claims of the present utility model.
Claims (5)
1. A protection circuit for a passive leakage current tester input test power supply, comprising: the device comprises a relay K1, a relay K2, voltage dividers (R1 and R2), an operational amplifier, a precision rectifying circuit, a low-pass filter and a detection ARM;
the relay K1 is used for switching an input power supply, and when the input power supply of the isolation transformer is detected, the relay K1 is attracted, and the input power supply is connected to the test circuit;
the relay K2 is a change-over switch for switching and measuring N, L phase power supply;
the voltage divider (R1, R2) is used for converting 220V voltage into 2.2V voltage which can be measured;
the precise rectification circuit is used for converting alternating voltage into alternating direct voltage;
the circuit of the low-pass filter is used for converting alternating direct-current voltage into stable direct-current voltage;
the detection ARM converts the analog voltage into digital quantity for judgment.
2. The protection circuit for a passive leakage current tester input test power supply of claim 1, wherein: the protection circuit further includes: the main control ARM is used for controlling the relay K1 and alarming a detection signal for detecting the ARM.
3. The protection circuit for a passive leakage current tester input test power supply of claim 2, wherein: the protection circuit further includes: and the isolation circuit is used for isolating signals of the main control ARM and the detection ARM.
4. A protection circuit for a passive leakage current tester input test power supply according to claim 3, wherein: after the ARM detection is judged to be finished, the result is transmitted to the main control ARM through the USART interface by isolating current.
5. The protection circuit for a passive leakage current tester input test power supply of claim 4, wherein: the 2.2V detection voltage is changed into the alternating-current direct-current voltage 2.2V after passing through the operational amplifier and the precise rectification circuit, and the voltage is changed into the stable direct-current voltage after passing through the low-pass filter and then is sent into the detection ARM.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202321658992.8U CN220086952U (en) | 2023-06-27 | 2023-06-27 | Protection circuit of passive leakage current tester input test power supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202321658992.8U CN220086952U (en) | 2023-06-27 | 2023-06-27 | Protection circuit of passive leakage current tester input test power supply |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN220086952U true CN220086952U (en) | 2023-11-24 |
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ID=88815578
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202321658992.8U Active CN220086952U (en) | 2023-06-27 | 2023-06-27 | Protection circuit of passive leakage current tester input test power supply |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN220086952U (en) |
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2023
- 2023-06-27 CN CN202321658992.8U patent/CN220086952U/en active Active
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