CN1021928C - Instrument with electronic brain for mechanical property of asynchronous motor - Google Patents

Abstract

The present invention relates to an instrument with an electronic brain for the mechanical property of an asynchronous motor. A single-board computer is introduced as the core technology. By a no-load method and a software differential method, the torque-speed characteristic of the asynchronous motor, the dynamic rotary speed of various rotary machines, relevant acceleration, the relation of any electric variable quantity and the rotary speed, and the rotary inertia of the rotary machine can be measured. The mechanical characteristic of blades and a separation point of a centrifugal switch of a single-phase asynchronous motor during the starting process are measured. The data and the curve can be immediately printed. The present invention has the advantages of simple structure, low cost, high measuring precision, no excessive heating danger to a motor, electrical energy saving, easy and flexible use, etc.

Description

Instrument with electronic brain for mechanical property of asynchronous motor

The present invention is the surveying instrument of mechanical properties such as a kind of torque-speed characteristic about asynchronous motor, various electric variable-rotary speed property, moment of inertia, static state, dynamic rotating speed and acceleration thereof, this instrument is applicable to various asynchronous motors, is not subjected to the restriction of its capacity, structure rotating speed.

At present, the measuring method of mechanical characteristics of motor can be divided into two big classes: the method and the no-load method of carrying arranged.It is earlier electric motor starting to be arrived stabilized (steady-state) speed that the method for carrying is arranged, and by the loading equipemtn pointwise load is added on the motor then, draws mechanical property by secondary instrument and X-Y recorder.This method equipment complexity, power consumption be many, install and use inconvenience, and temperature rises, and influences measuring accuracy.But owing to easily realize, thereby most of surveying instrument has all adopted the method for carrying.No-load method is measured in empty load of motor starting and coasting process, has avoided the above-mentioned shortcoming that the method for carrying is arranged, but has implemented the comparison difficulty." motor torque-rotary speed property tester " that Shenyang precision instrument factory produces is exactly to adopt no-load method, and it utilizes the RC circuit that tach signal is carried out differential, thereby obtains acceleration signal, delivers to then that oscillograph shows, taking pictures obtains the relative value of torque.This instrument is subjected to disturb greatly, calibration is difficult, precision low (5%).Thereby be not used in the test of middle and small motor, only be used to lack the occasion of other testing apparatus.

In addition, regardless of being no-load method or the method measurement instrument of carrying being arranged, all can only measure static rotating speed, the torque-speed characteristic of motor.And under many occasions, need know the moment of inertia of rotating machinery, the rub relation of torque and rotating speed of wind, dynamically rotating speed and relevant acceleration, the family curve of various electric variables and rotating speed.This is a long-term unsolved problem.

The objective of the invention is to design one is the complete novel induction motor mechanical property tester of core with the single card microcomputer.It can test the many mechanical properties of asynchronous motor, comprises being difficult to the mechanical property measured in the past.Be the analysis of electric rotating machine series products, development facilitates.

The present invention is made up of single board computer [3], photoelectric sensor [1], photo signal channel [2], voltage transmitter [4], electromagnetic signal passage [5], shaping square wave monitoring line parts such as [9] with keyboard input [6], display [7], printer [8], referring to figure one.Wherein photo signal channel carries out shaping sending into a comparer from the irregular tachometer signal of photoelectric sensor output with reference voltage, reference voltage can be regulated size arbitrarily by a potentiometer, thereby can regulate the pulsewidth of tachometer pulse after the threshold values of trigger voltage and the shaping arbitrarily.Tachometer pulse after the shaping is delivered on the shaped pulse monitoring line on the one hand, observes in order to the user, sends into CPU through the incoming line of the PIO1 of single board computer on the other hand and carries out software processes, thereby obtain transient speed, instantaneous acceleration and torque.For the accuracy of measuring is in waiting status behind the computer booting, have only when motor (or other rotating machinery) Cai the moment that begins to rotate changes duty over to from waiting status.In order to show the tooth on the motor fluted disc and the relative position of photometer head, the light emitting diode of between photo signal channel comparator output terminal and 5V direct supply, having connected.The effect of electromagnetic signal passage be with the 3.4V sinusoidal signal one tunnel of the reflection motor terminal voltage of voltage transmitter output through the resistance and the negative limiting circuit of diode composition deliver to the comparer shaping, its output signal is imported CTC again.ADC is delivered on another road simultaneously, and the ZC/TO0 of CTC end links to each other with the START end of ADC, and the output signal of ADT is imported CPU through PIO2, and is provided by PIO2 and to interrupt applying for signal.In addition, if electromagnetic signal passage configuration corresponding software also can be used for testing the speed or measuring all electric variables that comprise electric current.The present invention measures torque can adopt calibration of machinery consumption or the calibration of falling bodies method.By the falling bodies method, the computing machine available software calculates the moment of inertia of rotating machinery, and its formula is as follows:

$\mathrm{J\; =}\frac{{\mathrm{mr}}^2\mathrm{(g\; -\; a\; )}}{{\mathrm{a\; +\; a}}_o}$

M is the quality of weight in the formula, and r is the radius of turn at rotating machinery wiring place, and a is the positive acceleration at radius of turn place, a ₀The absolute value of radius of turn place negative acceleration during for art skating.And computing machine is tried to achieve rotary acceleration by the software differential, and its formula is as follows:

$\mathrm{a\; =}\frac{\frac{1}{T_2}-\frac{1}{{\mathrm{<figure-callout\; id="1"\; label="T"\; filenames="871027763\_DRIMG1.png"\; state="\{\{state\}\}">T</figure-callout>}}_1}}{\frac{1}{2}{\mathrm{(<figure-callout\; id="2"\; label="T"\; filenames="871027763\_DRIMG1.png,871027763\_DRIMG2.png"\; state="\{\{state\}\}">T</figure-callout>}}_2{\mathrm{+\; T}}_1)}$

T in the formula ₁Be previous photoimpact cycle, T ₂Be a back photoimpact cycle.Single board computer can also use separately.

The present invention has also developed new purposes except the rotating speed that can test asynchronous motor, torque-speed characteristic.Measure the air-out torque-speed characteristic that rubs, (for example fan fan blade mechanical property), the measurement of monopole asynchronous motor starting process centrifugal switch burble point.The moment of inertia of rotating machinery, the relation of arbitrary electric variable and rotating speed, dynamically rotating speed and corresponding acceleration thereof etc.As long as rotating machinery just can show measured data immediately through a starting under no load calibration back (or coasting calibration back), print tested family curve and data.These purposes are provided convenience for analysis, the development to the rotating machinery series products from now on.For example the rub relation of torque and rotating speed of the relation of axle output torque and rotating speed and wind is to design the foundation of fan.

The present invention is owing to adopt no-load method to measure, and introduced single board computer and make measurement result digitizing, measuring operation robotization, measure variation as core technology, and apparatus structure is simple, reliable operation, do not had overheated danger by measured motor, measure rapidly, easy to use flexible, antijamming capability is strong, the precision height is saved electric energy, and cost is lower, there is multiple measurement purposes available, has tangible technical economic benefit.

Figure one is the block diagram of mechanical characteristics of motor test, and figure two is circuit diagrams of photo signal channel and electromagnetic signal passage.

The present invention has made product, and the motor of Multiple Type is tested, and the result reaches specification requirement fully. Product structure and parameter are referring to figure one and figure two, the ZHG infrared photoelectric sensor is made up of 2GL infrarede emitting diode and 3DU2 phototriode, and consistent with single board computer in order to make its power supply, the light emitting diode biasing resistor is 220 Ω, the phototriode biasing resistor is 160K Ω, and supply voltage is 5V. The no-load voltage ratio of voltage transmitter is 400: 3.4(or 230: 3.4,110: 3.4). Single board computer adopts the TP-801B type. The used four comparator models of signalling channel are LM339. ADC modulus conversion chip model is ADC0809.

Claims (3)

1, induction motor mechanical property instrument with electronic brain, its ingredient has: has the keyboard input, shows, have the single card microcomputer [3] of print data and curve, photoelectric sensor [1], photoelectricity transmitter [4] is characterised in that following ingredient in addition:

A) photo signal channel [2] can be regulated its reference voltage just with the output signal of photoelectric sensor by the potentiometer regulator with one and be input to a comparer, and comparator output signal is input on the incoming line of PIO1 again,

B) electromagnetic signal passage [5] is delivered to a comparer with the output signal one tunnel of voltage transmitter through the negative limiting device of resistance and diode composition, and the output signal of comparer is input to CTC again, and ADC is delivered on another road simultaneously,

C) photoelectric sensor [1], its 2GL infrarede emitting diode biasing resistor is 220 Ω, and 3DU2 phototriode biasing resistor is 160K Ω, and supply voltage is 5V,

D) shaping square wave monitoring line [9] is drawn from the shaping comparer.

2, induction motor mechanical property instrument with electronic brain according to claim 1 is characterized in that the power supply of described photo signal channel [2] links to each other with comparator output terminal through the branch road that resistance and light emitting diode are in series.

3, induction motor mechanical property instrument with electronic brain according to claim 1 is characterized in that the ZC/TO0 end of the CTC of described electromagnetic signal passage [5] links to each other with the START end of ADC, the output signal of ADC is input to CPU through PIO2, and provides interruption application signal by PIO2.

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