CN2046630U

CN2046630U - A.c. current detecting device

Info

Publication number: CN2046630U
Application number: CN 89211509
Authority: CN
Inventors: 夏奇工
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-03-10
Filing date: 1989-03-10
Publication date: 1989-10-25

Abstract

The utility model discloses an alternating current detecting device which is formed by electrically connecting a miniature transformer, an operational amplifier, resistors and capacitors. The utility model has the advantages of small size, low cost and good linearity, and the important thing is that the utility model saves lots of black and non-ferrous metallic materials.

Description

A.C. current detecting device

The utility model relates to a kind of AC current detection device.

In the existing technologies, detect alternating current and all use AC current transformer, the AC current transformer volume is big, cost is high, poor linearity, and needs to consume a large amount of black and nonferrous materials.

The purpose of this utility model is that the pick-up unit that a kind of volume is little, cost is low, the linearity is good will be provided.It need only mate a shunt and just can replace traditional mutual inductor during use, reaches the purpose that detects alternating current.

The utility model be achieved in that utilize shunt in tested alternating circuit, obtain one consistent with tested AC current phase, size has the very little ac voltage signal of linear transformation feature.This voltage signal is isolated through a miniature transformer, again through the operational amplifier linear amplification, or linear amplification rectification, just can obtain one at the output terminal of operational amplifier and not have connecting on the circuit with circuit-under-test, have input AC or the d. c. voltage signal that the converting characteristic of linear relationship, reflection is fast, phase place is consistent Gong control circuit or indicating instrument use with tested electric current, therefore use this device to replace AC current transformer and in alternating circuit, carry out alternating current and sample with shunt.

This device is owing to use components and parts few, and line construction is simple, and the linearity is good, has only used a miniature transformer in the circuit.Therefore volume is little, and cost is low, power consumption is little, can save a large amount of black and nonferrous materials for country, and can be extended to new instrument, instrument series of products according to user's needs.

Concrete structure of the present utility model is provided by following embodiment and accompanying drawing thereof.

Fig. 1 is a basic circuit diagram of the present utility model.

Fig. 2 is a concrete application examples circuit diagram of the present utility model.

With reference to Fig. 1, this device is by a miniature transformer B, operational amplifier IC, two capacitor C ₁And C ₂, two resistance R i and Rf, lead be installed in the housing after electrically connecting.1,2 is the input end of this device among the figure, links with the output terminal of external shunt FL; 3 is earth terminal; 4,5 is amplifier external power supply terminals; 6 are this device output terminal.

Described miniature transformer iron core tongue is wide to be the E font cold-reduced silicon sheet of 6mm, and every thick δ=0.35mm intersects lamination, and folded thick is 8mm, and elementary winding is 1100 circles, and secondary winding is 2200 circles, is φ=0.10mm high strength enamelled wire.Requiring to insulate between primary and secondary is also technology baking routinely, dipping lacquers of 1000 megohmmeter survey 〉=0.5m Ω.Can adopt IJ79 iron-nickel alloy or IJ16 ferroaluminium to make iron core if be used for the high occasion of accuracy requirement.Described operational amplifier can adopt integrated circuit, and model is the arbitrary unit among the LM324, also can form with discrete component.

When single power supply 1.5～30V; During dual power supply be ± 1.5～± 15V.

Fig. 2 is that this device is used in the concrete application circuit of three-phase bridge circuit as the main circuit current measuring unit, and it can also be used for the sample circuit of asynchronous motor overload, phase shortage and star triangle automatic change over, can develop into new series of products.

During use, the shunt of serial connection 75mv in tested main circuit, the input end of the output termination detecting device of shunt, if to this device add dual power supply ± 1.5～± 15V, can output terminal obtain with tested size of current be directly proportional phase place consistent and on circuit connectionless alternating voltage; (1.5～30V) can obtain Chenging Zheng Bi And connectionless DC voltage on circuit with tested voltage swing at output terminal if this device is added single supply.

Claims

1, a kind of novel AC current detection device comprises lead, housing, it is characterized in that also comprising that a miniature transformer, operational amplifier, resistance, electric capacity form through electrical connection.

2, detecting device according to claim 1 is characterized in that the input end of described transformer is connected with the output terminal of external shunt, and an end of operational amplifier is an output terminal.