CN216117801U

CN216117801U - Interference elimination circuit for inductive load in grounding resistance test

Info

Publication number: CN216117801U
Application number: CN202122622409.5U
Authority: CN
Inventors: 杨雪冬
Original assignee: Nanjing Minsheng Electronic Instruments Co ltd
Current assignee: Nanjing Minsheng Electronic Instruments Co ltd
Priority date: 2021-10-29
Filing date: 2021-10-29
Publication date: 2022-03-22
Anticipated expiration: 2031-10-29

Abstract

The utility model discloses an interference elimination circuit for an inductive load in a ground resistance test, which comprises an output large-current transformer, wherein the input end of the output large-current transformer is connected with a supply current, the output end of the output large-current transformer is connected with a sensed load, the rising time of the current at the output side of the output large-current transformer is set to be fixed time, and the rising speed of the current and the voltage at the output side of the output large-current transformer is stable.

Description

Interference elimination circuit for inductive load in grounding resistance test

Technical Field

The utility model relates to the technical field of electronics, in particular to an interference elimination circuit for an inductive load in a ground resistance test.

Background

The automatic earth resistance tester which is commonly used in the market at present drives a large-current output transformer through a power amplifier to output current, tests the voltage at two ends of a load to be tested through a four-terminal network, and then divides the voltage by the output current to obtain the resistance. If the current changes due to the change of the power supply voltage or the resistance to be detected, the current is judged by the mcu through ad sampling, and then the output current is controlled through the output magnitude of the power amplifier to obtain the effect of constant current. Although the testing method is simple and intuitive and is still used for testing pure resistors, if the resistors with inductive loads are tested, the current lags due to the inductive action, the obtained resistors are larger, and false alarms are caused.

SUMMERY OF THE UTILITY MODEL

The present invention is directed to a circuit for eliminating interference of an inductive load in a ground resistance test, so as to solve the above problems in the prior art.

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

the interference eliminating circuit for inductive load in ground resistance test includes one large output current transformer with input connected to the power supply current and output connected to the sensed load, and the transformer has output side current rising time set in fixed time and stable voltage rising speed.

As a further technical solution of the present invention, a voltage sensor is connected in parallel to both ends of the sensed load.

As a further technical solution of the present invention, a current sensor is provided on the sensed load loop.

Compared with the prior art, the utility model has the beneficial effects that: the grounding resistance tested by the utility model can obviously reduce the test data error caused by asynchronous change of current and voltage under inductive load, greatly improve the test precision, reduce the times of false alarm, reduce the test failure rate of finished products, and greatly improve the production efficiency of enterprises and the waste of production resources.

Drawings

Fig. 1 is a circuit diagram of the present invention.

Fig. 2 is a graph of the current-voltage variation of a prior art inductive load.

Fig. 3 is a signal diagram of a voltage-current alternating current signal after detection in the prior art.

FIG. 4 is a diagram of the voltage-current AC signal after detection according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1 and 4, example 1: the interference eliminating circuit for inductive load in ground resistance test includes one large output current transformer with input connected to the power supply current and output connected to the sensed load, and the transformer has output side current rising time set in fixed time and stable voltage rising speed. Firstly, the current rising time can be set to make the current rise slowly, so that in the course of current rising slowly, the influence of reverse electromotive force on current can be reduced as far as possible, and the current and voltage can be smoothly and synchronously raised, if it has to quickly reach fixed current because of the problem of test speed, it also can be set in the course of current rising, and can not judge that the resistance is exceeded or not, and can make judgment until the current is stable, and in the course of test, if the current is changed because of sudden change of resistance, the current also can be regulated again, and can be regulated and stabilized, and can start to judge resistance of load to be tested, so that the ground resistance tested by adopting the above-mentioned new method can obviously reduce test data error due to asynchronous change of current and voltage under the inductive load, and can greatly raise test accuracy, and can reduce false alarm frequency, the test failure rate of finished products is reduced, the production efficiency of enterprises is improved, and the waste of production resources is greatly improved.

In embodiment 2, a voltage sensor is connected in parallel to both ends of the sensed load in addition to embodiment 1. The current sensor is arranged on the sensed load loop.

It will be evident to those skilled in the art that the utility model is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the utility model being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. The interference eliminating circuit for inductive load in ground resistance test includes one large output current transformer, and features that the large output current transformer has its input connected to the power supply current and its output connected to the sensed load, and the output current transformer has output current with rising time set in fixed time and stable rising speed of output current and voltage.

2. The interference cancellation circuit for an inductive load in a ground resistance test as claimed in claim 1, wherein a voltage sensor is connected in parallel to two ends of the sensed load.

3. The interference cancellation circuit for an inductive load in a ground resistance test as claimed in claim 1, wherein a current sensor is disposed on the loop of the sensed load.