CN2483878Y

CN2483878Y - Microelectronic motor protector with high performance price ratio

Info

Publication number: CN2483878Y
Application number: CN 01237709
Authority: CN
Inventors: 张培铭; 吴功祥; 鲍光海; 许志红
Original assignee: Fuzhou University
Current assignee: Fuzhou University
Priority date: 2001-05-06
Filing date: 2001-05-06
Publication date: 2002-03-27
Anticipated expiration: 2011-05-06

Abstract

The utility model discloses a microelectronic motor protector with high performance-cost ratio, the three-phase current transformers are respectively parallelly connected with resistances to change current signals into voltage signals, the output end of the amplifying circuit is connected with the input end of the V/F converter, the V/F converter changes voltage signals into digital pulse signals, the mcu system without A/D respectively judge the counting values of three-phase current signals and power voltage sampling signals to determine whether the system has fault. Compared with the present technology, the utility model is an a reliable device with the main protection function of motor overload, break phase, stall, three-phase imbalance, over-voltage and under-voltage.

Description

A kind of microelectronics type motor protector of high performance-price ratio

The utility model belongs to a kind of electric motor protector, belongs to generating, power transformation or the distribution class of electric power.

Because bimetal thermal relay unstable properties, defencive function are poor, the developing direction of motor protector is to adopt the motor protector of microelectronic chip.By retrieval as can be known; existing product of all kinds of electronic type or intelligent motor protector and argumentation at present; the paper of delivering on " electric switch " magazine 1999.No3 at the paper of delivering on " electrotechnics " magazine 2000.No6 " a kind of new Digital motor comprehensive protection device ", Xu Shuyan with Zhang Lian etc. " a kind of electronic type motor protection relay design " is representative, is typical products with the products such as the electronic supervisory control system JDB-LQ series of intelligent digital display of the two magnificent Electric Applicance Co., Ltd in Cangnan, Zhejiang.Yet only having that these schemes have transshipped or phase failure protection function, employing circuit complexity that has and the high singlechip chip of price, and therefore, these schemes or performance index are low or price is high, can't obtain large scale application.

The purpose of this utility model is exactly at above-mentioned deficiency, and a kind of low microelectronics type motor protector of main defencive function, performance index height and cost with overload, the phase failure, stall, three-phase imbalance, overvoltage, under voltage of development.

The purpose of this utility model is to realize like this, its threephase current transformer is in parallel with resistance respectively, current signal is converted to voltage signal, the voltage signal of the voltage signal of resistance output and power transformer output is connected to four input ports of multiway analog switch respectively through rectification circuit, signal after channel selecting is connected to the peak value sampling circuit through the output of multiway analog switch, signal behind the peak value sampling is connected to amplifying circuit through output, the input of the output of amplifying circuit and V/F converter joins, the V/F converter is converted to digital pulse signal with voltage signal, the digital pulse signal of output is connected to through the V/F converter output terminal and cheap does not count with the input port of the Single Chip Microcomputer (SCM) system of A/D, respectively the count value of three-phase current signal and supply voltage sampled signal is not judged and determined whether fault with the Single Chip Microcomputer (SCM) system of A/D, if fault, the delivery outlet with the Single Chip Microcomputer (SCM) system of A/D does not send trip signal and drives indicator light and relay through drive circuit.

The utility model compared with prior art is a kind of reliable operation, have electromotor overload, the phase failure, stall, three-phase imbalance, overvoltage, under voltage main defencive function, to carry out accurate counting, circuit to signal value simple and adopt not with the low motor protector of the cost of A/D single-chip microcomputer.

Below with reference to accompanying drawing utility model is further described

Fig. 1 is a structural representation of the present utility model

Fig. 2 is a schematic block circuit diagram of the present utility model

Fig. 3 is a software schematic block diagram of the present utility model

Among the figure, Z1, Z2, Z3 are threephase current transformer; R1, R2, R3 are resistance; Z4 is a power transformer; X1, X2, X3, X4 are rectification circuit; D is not for the Single Chip Microcomputer (SCM) system of A/D; E1 is a multiway analog switch; E2 is the peak value sampling circuit; E3 is an amplifying circuit; E4 is the V/F converter; E5 is a drive circuit; E6 is indicator light and relay.

As can be seen from Figure 1, the signal of threephase current transformer Z1-Z3 and power transformer Z4 output is delivered to count pulse and is produced and control system K, setting current regulator potentiometer W and K join, and Single Chip Microcomputer (SCM) system D is by the K counting and send signal to K, and K is connected to indicator light and relay E6.

As can be seen from Figure 2, its annexation is that threephase current transformer Z1-Z3 is in parallel with resistance R 1-R3 respectively, current signal is converted to voltage signal, the voltage signal of the voltage signal of R1-R3 output and power transformer Z4 output is connected to four input ports of multiway analog switch E1 respectively through rectification circuit X1-X4, signal after channel selecting is connected to peak value sampling circuit E2 through the output of multiway analog switch E1, signal behind the peak value sampling is connected to amplifying circuit E3 through the E2 output, the input of the output of E3 and V/F converter E4 joins, E4 is converted to digital pulse signal with voltage signal, the digital pulse signal of output is connected to through the E4 output and cheap does not count with the input port of the Single Chip Microcomputer (SCM) system D of A/D, D judges the count value of three-phase current signal and supply voltage sampled signal respectively and determines whether fault, if fault, the delivery outlet of D sends trip signal and drives indicator light and relay E6 through drive circuit E5.

As can be seen from Figure 3; Single Chip Microcomputer (SCM) system D at first carries out initialization; judge then whether supply voltage meets the requirements; just send switching signal if meet the requirements; then carry out current-voltage sampling and judge whether the phase failure or three-phase imbalance; be then to enter the phase failure and three-phase imbalance defence program; otherwise proceed overvoltage or under-voltage judgement; be then to enter the over-and under-voltage defence program, otherwise judge whether stall, if then enter the rotation-clogging protection program; otherwise whether transship judgement; be then to enter the overload protection program, otherwise carry out current-voltage sampling again that so circulation is carried out.

From as can be known top: threephase current transformer Z1-Z3, resistance R 1-R3, power transformer Z4, rectification circuit X1-X4, not with the Single Chip Microcomputer (SCM) system D of A/D, multiway analog switch E1, peak value sampling circuit E2, amplifying circuit E3, V/F converter E4, drive circuit E5, indicator light and relay E6, its annexation is that threephase current transformer Z1-Z3 is in parallel with resistance R 1-R3 respectively, current signal is converted to voltage signal, the voltage signal of the voltage signal of R1-R3 output and power transformer Z4 output is connected to four input ports of multiway analog switch E1 respectively through rectification circuit X1-X4, signal after channel selecting is connected to peak value sampling circuit E2 through the output of multiway analog switch E1, signal behind the peak value sampling is connected to amplifying circuit E3 through the E2 output, the input of the output of E3 and V/F converter E4 joins, E4 is converted to digital pulse signal with voltage signal, the digital pulse signal of output is connected to through the E4 output and cheap does not count with the input port of the Single Chip Microcomputer (SCM) system D of A/D, D judges the count value of three-phase current signal and supply voltage sampled signal respectively and determines whether fault, if fault, the D delivery outlet sends trip signal and drives indicator light and relay E6 through drive circuit E5.

Claims

1. the microelectronics type motor protector of a high performance-price ratio; it is characterized in that: threephase current transformer (Z1; Z2; Z3) respectively with resistance (R1; R2; R3) parallel connection; resistance (R1; R2; R3) voltage signal of Shu Chu voltage signal and power transformer (Z4) output is respectively through rectification circuit (X1; X2; X3; X4) be connected to four input ports of multiway analog switch (E1); signal after channel selecting is connected to peak value sampling circuit (E2) through the output of multiway analog switch (E1); signal behind the peak value sampling is connected to amplifying circuit (E3) through (E2) output, and the input of the output of amplifying circuit (E3) and V/F converter (E4) joins.