传感器原理传感器原理 (25).ppt

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1、Principle of Sensors传感器原理电感式传感器Inductive Sensors 4.3.3 电涡流传感器的应用 Application of Eddy Current Sensor 电涡流传感器的应用电涡流传感器的应用电涡流传感器的应用电涡流传感器的应用 Application of Eddy Current Sensor Application of Eddy Current Sensor 电涡流传感器以其长期工作可靠性好、测量范围宽、灵敏度高、分辨率高、响应速度快、抗干扰力强、不受油污等介质的影响、结构简单等优点，在大型旋转机械状态的在线监测与故障诊断中得到广泛应用。Ed

2、dy current sensor is widely used in on-line monitoring and fault diagnosis of large rotating machinery because of its advantages of long term working reliability,wide measuring range,high sensitivity,high resolution,fast response speed,strong anti-interference,no influence ofOil and other media,and

3、simple structure.主要应用主要应用主要应用主要应用Main Applications:Main Applications:（1）测厚：低频透射式涡流厚度传感器,高频反射式涡流厚度传感器（2）测转速（3）测位移、测振动（4）电涡流探伤（5）金属零件计数、尺寸检测、光洁度检测。(1)Thickness measurement:Low frequency transmission eddy current thickness sensor;High frequency reflective eddy current thickness sensor(2)Measuring rotat

4、ional speed(3)Measuring displacement and vibration;(4)Eddy current inspection;(5)Counting of metal parts,dimension detection and smoothness detection.测厚（低频透射式涡流厚度传感器）测厚（低频透射式涡流厚度传感器）测厚（低频透射式涡流厚度传感器）测厚（低频透射式涡流厚度传感器）Thickness measurement(low frequency transmission eddy current thickness sensor)Thickne

5、ss measurement(low frequency transmission eddy current thickness sensor)在金属板的上下方分别设有发射传感器线圈L1和接收传感器线圈L2，L1加低频电压U1时，L1上产生交变磁通。无金属板时，磁通直接耦合至L2，L2产生感应电压；如果金属板放置两线圈之间，线圈L1在金属板中产生电涡流，磁场能量受到损耗，使达到L2的磁通减弱，最终使L2上感应电动势减弱。金属板越厚，涡流磁能损失越多，下线圈L2上感应电动势输出U2越小。通过测量U2检测金属板的厚度。透射式涡流传感器可检测1100mm范围。A transmitting senso

6、r coil L1 and a receiving sensor coil L2 are respectively arranged on the upper and lower parts of the metal plate.When a low-frequencyvoltage U1 is applied to L1,an alternating magnetic flux is generated on L1.When there is no metal plate,the magnetic flux is directly coupled to L2,and L2generates

7、induced voltage;If the metal plate is placed between two coils,the coils L1 produces eddy current in the metal plate,and the magnetic field energy is lost,which weakens the magnetic flux reaching L2 and finally weakens the induced electromotive force on L2.The thicker the metal plate is,the more edd

8、y current magnetic energy loss is,and the smaller the induced EMF output U2 on the lower coil L2 is.Measure the thickness of metal plate by measuring U2.Transmission eddy current sensor can detect the range of 1 100mm.测厚（高频反射式涡流厚度传感器）测厚（高频反射式涡流厚度传感器）测厚（高频反射式涡流厚度传感器）测厚（高频反射式涡流厚度传感器）Thickness measurem

9、ent(high frequency reflective Thickness measurement(high frequency reflective eddy current thickness sensor)eddy current thickness sensor)1、当厚度不变时，两传感器与上下表面距离 x1+x2=常数;2、传感器输出电压之和（假设为 2U），数值不变；3、当厚度变化 时,输出电压=2UU，可将U 放大输出显示带材厚度变化。实际应用时，给定厚度，当厚度变化时与厚度变化值的代数和就是被测带材厚度。1、When the thickness is constant,th

10、e distance between the two sensors and the upper and lower surfaces x1+x2=constant;2、The sum of sensor output voltages(assumed to be 2U),the value is unchanged;3、When the thickness changes,the output voltage=2UU,U can be amplified and output to show the thickness change of strip.In practical applica

11、tion,given the thickness,the algebraic sum of the thickness change and the thickness change value is the measured strip thickness.涡流转速测量涡流转速测量涡流转速测量涡流转速测量 Eddy current speed measurement Eddy current speed measurement 被测体是金属或磁性齿轮可计算出齿轮每分钟转速The measured body is a metal or magnetic gear,and the speed p

12、er minute of the gear can be calculated N=（f/n）60式中：f 为检测的频率;n为齿数；F is the frequency of detection;N Number of teeth;工业常用 60齿，则：N=f60 teeth commonly used in industry,N=f 无损检测无损检测无损检测无损检测Non-destructive testing Non-destructive testing 电涡流式传感器可以对被测对象进行非破坏性的探伤，例如检查金属的表面裂纹、热处理裂纹以及焊接部位的探伤等。在检查时，使传感器与被测体的距

13、离不变，如有裂纹出现时，导体电阻率、磁导率发生变化，从而引起传感器的等效阻抗发生变化，通过测量电路达到探伤的目的。Eddy current sensors can be used for non-destructive flaw detection,such as surface cracks of metal,heat treatment cracks and flaw detection of welding parts.During the inspection,the distance between the sensor and the measured body is unchan

14、ged.If there is a crack,the resistivity and permeability of the conductor change,which causes the equivalent impedance of the sensor to change.The purpose of flaw detection is achieved by measuring the circuit.现场检测实施图现场检测实施图现场检测实施图现场检测实施图On-site inspection implementation On-site inspection implementation diagramdiagram