CN2272162Y

CN2272162Y - Computerized motor protection

Info

Publication number: CN2272162Y
Application number: CN 96223698
Authority: CN
Inventors: 杜炎森; 郑建勇; 胡敏强
Original assignee: Southeast University
Current assignee: Southeast University
Priority date: 1996-09-19
Filing date: 1996-09-19
Publication date: 1998-01-07
Anticipated expiration: 2006-09-19

Abstract

The utility model relates to a motor protection device which utilizes a microcomputer, and is an electromechanical protection device for motors. The utility model is composed of a signal input and conditioning circuit, an analog-to-digital conversion circuit, a main control unit, and a keyboard input, display and output protection circuit. The input end of the analog-to-digital conversion circuit is connected with the output end of the signal input and conditioning circuit, and the output end of the analog-to-digital conversion circuit is connected with the input end of the main control unit. The keyboard input, display and output protection circuit is directly connected with the main control unit. The signal collection part of the signal input and conditioning circuit adopts a current transformer and a voltage transformer, and respectively collects the phases A and C and the zero sequence current of the power supply, and the voltage signal of the power supply.

Description

Adopt the motor protecting device of microcomputer

The utility model is a kind of employing system controlled by computer, and the equipment that big-and-middle-sized alternating current motor is carried out relaying protection belongs to the motor protection apparatus technology automatically.

When motor moves under abnormal state; may cause the damage of motor; this has not only damaged motor; and cause the pause of production or the expansion of accident; especially its economic loss that causes of large and medium motor is considerable; must take safeguard measure, i.e. the relaying protection of motor for this reason.

Relay, transistor and three developing stage of protection using integrated circuit have been experienced in the relaying protection of big-and-middle-sized alternating current motor.More than protect the defective of equal various degrees; as poor sensitivity, the accuracy of adjusting is low, Operation and Maintenance is inconvenient, can produce malfunction or tripping, poor reliability etc.; the motor integrated circuit comprehensive protector that gets up as domestic and international immediate development; when long-term on-line operation; because the influence of the dispersiveness of element and stability; the null offset phenomenon can occur, cause the misoperation of protector.In addition, integrated circuit type protector line complexity, easy care not, action setting value and Stateful Inspection are directly perceived inadequately, particularly in the heat protection, can't set up the hot memory models of accurate analysis and calculating, the heat protection is waited seem more coarse.Can not satisfy the requirement of modern production fully to big-and-middle-sized protecting AC motor.

Goal of the invention of the present utility model provides a kind of to motoring monitoring, the motor protecting device of the employing microcomputer of early warning and protection.

The utility model mainly by signal input and nurse one's health 1, A/D conversion 2, main control unit 3, keyboard input with show 4, output protection 5 constituted; the output of input of the input termination signal of A/D conversion and conditioning wherein; the input of the output termination main control unit of A/D conversion, the keyboard input directly is connected with main control unit with output protection with demonstration.Wherein signal and modulate circuit are mainly formed the forward-order current signal conditioning circuit by " U11A, U11B, U10A ", form the negative-sequence current signal conditioning circuit by " U17A, U17B, U10B ", form the voltage signal modulate circuit by " U15B ", form the zero sequence current signal modulate circuit by " U15A ".The A/D change-over circuit comprises integrated circuit U1, U8, and main control unit is made up of single chip microcomputer " U2 ", and the keyboard input mainly is made up of U5, U6 with demonstration, and output protection mainly is made up of transistor Q1, Q2, Q3, Q4 and peripheral circuit thereof.In signal input and modulate circuit, the signal input pickup adopts current transformer and voltage transformer, with A, the C of motor mutually and zero sequence current signal and power supply voltage signal be input to i.e. " ICI, IAI, IOI, VI " end of signal input part in signal input and the conditioning, the output of signal input and modulate circuit promptly " I1, I2, I00, U0 " respectively with the A/D change-over circuit in " S1, S2, S3, S4 " end of U8 join,, join as output by integrated circuit U8 " OUT " end with " 20VIN " end of A/D change-over circuit U1.Directly send into the single chip microcomputer " U2 " of main control unit handles through the signal of A/D change-over circuit conversion." P1.2, P1.3 " end that the input of output protection " P12, P13 " is distinguished U2 in direct and the main control unit joins.The output of output protection circuit is by the protected motor of relay switch K1, K2 control and protection back level.

The operation principle of this device is: the A of motor power mutually and the C phase current introduce after by the current transformer unsteady flow.The C phase current is in signal input and modulate circuit, input " ICI " introducing of " C " phase current signal is through 60 of the U11A formation " after the accurate phase-shift circuit phase shift; pass through the U11B vector addition with the A phase current; obtain forward-order current, behind the second-order active filter circuit filtering that U10A constitutes, export from output I1; In like manner " A " phase current signal is through the input of " IAI " end, and " I2 " holds output.Zero-sequence current is held through going into from " IOI " after the current transformer unsteady flow, and through the filtering that U15A constitutes, export from " I00 " end amplifying circuit conditioning back.Line voltage after " UI " end is introduced, is held output from " U0 " through the instrument transformer step-down after the filter amplification circuit conditioning that U15B constitutes.Positive sequence, negative phase-sequence, zero-sequence current and the mains voltage signal analog gate circuit U 8 in the A/D change-over circuit through signal input and modulate circuit output is sent into A/D converter U1; the signal of being changed by A/D converter is sent into single chip microcomputer and is handled; judge and compare automatically with the parameter tuning value; with failure judgement character; and send corresponding execution signal to output protection circuit; send alarm or trip signal by this circuit control motor; simultaneously the fault in the display unit show lamp bright, show nature of trouble and fault value, finish defencive function.

Advantage of the present utility model is as follows:

1, function is more complete: this device has the function of short-circuit protection, unbalance protection, ground protection, mistake, under-voltage protection, heat memory, temperature alarm.

2, automaticity height: this device adopts microcomputer to carry out signal processing, utilizes the software compute mode to protect the analysis of setting value, has simplified hardware circuit greatly, has improved the reliability and the antijamming capability of complete machine effectively.

3, accuracy height: owing to adopted the microcomputer compute mode to analyze, solved the difficult problem in the processing of heat load and heat accumulation, the reliability of control is further improved.

4, structure is simpler, in light weight, volume is little, operation and maintenance is convenient; Adopt the operation of keyboard-type and adjust, can realize the input of protecting and withdraw from and the inspection of setting value by keyboard, therefore very easy to use.

Fig. 1 is a structured flowchart of the present utility model.

Fig. 2 is circuit theory diagrams of the present utility model.

Fig. 3 is the left-half of Fig. 2.

Fig. 4 is the right half part of Fig. 2.

Embodiment of the present utility model is as follows:

The model of A/D converter ic U1 is " AD574 ", the model of single chip microcomputer U2 is " INTEL 8751 ", U3 is " 7705 ", U4 is " 24C02 ", and U5 is " 8279 ", and U6 is " 16 U8 ", U7 is " TC232 ", U8 is that " AD 7503 " U11, U15, U17, U18 are " 1558 " operational amplifier, and signals collecting current transformer and voltage transformer in signal input and the conditioning are gathered A phase, C phase and zero-sequence current and power supply voltage signal respectively.Setting value is imported by keyboard, adopts the software compute mode that input signal is handled.According to the above, just can form the motor protecting device of employing microcomputer of the present utility model.

Claims

1. one kind is adopted the motor protecting device of microcomputer to be made up of signal acquisition circuit, signal processing circuit and output control circuit; it is characterized in that this device is imported by signal and conditioning (1), A/D conversion (2), main control unit (3), keyboard input and demonstration (4), output protection (5) are constituted; wherein the output of (1) is imported and nursed one's health to the input termination signal of A/D conversion (2); the input of the output termination main control unit of A/D conversion (2), the keyboard input directly is connected with main control unit (3) with output protection (5) with showing (4).

2. the motor protecting device of employing microcomputer according to claim 1; it is characterized in that the signal input pickup adopts current transformer and voltage transformer in signal input and the conditioning (1); with A, the C of motor mutually and zero sequence current signal and power supply voltage signal be input to signal input part in signal input and the conditioning (1), i.e. " CI, IAI, IOI, VI " end.

3. the motor protecting device of employing microcomputer according to claim 1 is characterized in that input " P12, P13 " " P1.2, P1.3 " end direct respectively and the middle U2 of main control unit (3) of output protection (5) joins.