2023년 3월 29일 수요일

BISOPE series 33 Simple vibration diagnosis and precision vibration dia...


BISOPE series 33- Simple vibration diagnosis and precision vibration diagnosis of rotating machinery

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The results of the vibration diagnosis can be confirmed as a technical report, which is largely divided into a simple diagnosis report and a detailed diagnosis report, etc., and is prepared including the cause and evaluation of the current vibration problem, and a description of countermeasures if necessary. The meaning of each report is a simple report in the case of simple evaluation of phenomena and absolute standards after temporary measurement, and detailed analysis to the extent that current causes can be analyzed and countermeasures can be found through spectrum analysis and cause analysis of various vibrations. are treated as detailed reports. In general, the definition of regular textbooks for facility diagnosis qualifications is not very different.

 

Simple diagnosis and precise diagnosis, offline and online

First of all, if you look at the methods of simple diagnosis, there are 'route measurement' and 'online monitoring system'. Inspection is commonly referred to as 'off-line' as a method in which humans intermittently investigate and record the state of equipment using a portable instrument (vibration meter, data collector). On the other hand, constant monitoring is a method of continuously monitoring by a monitoring device and is called 'on-line'. Inspection called off-line can measure many measurement points and directions, but it cannot be said to be continuous depending on the frequency of measurement. There are advantages and disadvantages between the two systems, since on-line continuously monitors and stores near real-time data from already installed sensors.

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All copyright  korea CBM  written by BISOPE , vs72@naver.com, 070-4388-0415,  www.kCBM.kr

#PDM; Resonance analysis, #frequency analysis, #CBM, #vibration sensor, #vibration and noise education


71 회전기계의 간이설비진단과 정밀설비진단


회전기계의 간이설비진단과 정밀설비진단

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진동진단의 결과는 기술보고서로 확인해 볼 수 있는데 이 것은 간이진단보고서와 정밀진단보고서 등으로 크게 구분하여 현재의 진동문제에대한 원인과 평가, 필요에 따라서 대책에 대한 기술등을 포함하여 작성된다. 각 보고서의 의미는 일시적 측정 후 간단히 현상과 절대기준 등의 평가를 한 경우는 간이보고서로, 스펙트럼분석과다양한 진동의 원인분석 등을 통해서 현재의 원인을 분석하고 대책을 구할 수 있을 정도의 상세한 분석은 정밀보고서로 다루어 진다. 대체로 설비진단 자격을 위한 정규 교과서 등에 이에 관한 정의도 크게 다르지 않다.

간이진단과 정밀진단 그리고 오프라인과 온라인

우선, 간이진단의 방법을 살펴보면 ‘점검(Route measurement)’과 ‘상시감시(Online Monitoring system)’가 있다. 점검은 흔히 설비의 상태를 인간이 포터블 계측기(진동계, Data collector) 등을 사용하여 간헐적으로 조사하고 기록하는 방법으로 'Off-line'이라고 부른다. 반면에 상시감시는 감시 장치에 의해 연속적으로 감시하는 방법으로 'On-line'이라고 하는데 off line이라 일컫는 점검은 많은 측정지점과 방향을 측정할 수 있으나 측정빈도에따라서 연속적이라고는 할 수 없고 ............

All copyright 한국CBM(주) written by BISOPE , vs72@naver.com, 070-4388-0415, www.kCBM.kr

관련 Tag

#PDM, #예지보전, #설비진단, #진동측정, #기계진단, #설비진단자격, #ISO18436, #진동분석, #진동진단보고서, #정밀진단보고서, #온라인모니터링시스템, #Route, #공진분석, #주파수분석, #CBM, #진동센서, #진동소음교육


2023년 3월 22일 수요일

BISOPE series 32 How is forced frequency different from natural frequency



BISOPE series 32- How is forced frequency different from natural frequency?

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When playing an acoustic guitar, when a guitar string is plucked according to a musical notation chord, each of the six strings (strings) generates a harmonic sound that shows a special timbre according to the chord, even if it produces a different sound. The guitar sound is unique for each string, and the pitch of the sound is different from each other. To understand this reason, if you take a good look at it with a little common sense, you can understand that the sound is 'uniquely different' depending on the length of the guitar string being plucked, the type of guitar string, and the degree to which the guitar string is tightened.

On the other hand, the vibration generated when the fan is operated, and the RPM (revolutions per minute) that fluctuates whenever the accelerator is pressed are different from the unique characteristics of the above guitar strings. In other words, this is a newly created thing, a 'forced creation', on the other hand, it is different from what the guitar string originally had, in other words, it does not generate sound at all unless it is plucked by hand.

 

Forced frequency

 

When a force is applied, both a natural frequency and a forced frequency occur, but .....

 

All copyright  korea CBM  written by BISOPE , vs72@naver.com, 070-4388-0415,  www.kCBM.kr

Vibration/Displacement/Measurement/Analysis/Cause Analysis/Monitoring System Design/Building Vibration Noise/Structural Vibration/Rotating Machine Vibration/Resonance Analysis/Feature Frequency/FFT/Facility Diagnosis/Early Fault Diagnosis/Noise Vibration Frequency Analysis/Vibration Soundproofing/Plant Vibration noise/construction site construction road/railway/measuring equipment and sensor consulting/PDM,CBM,VMS,CMS/machine-structure-piping-building-construction site-railway/monitoring system (HW, SW) design/MODAL/ODS/vibration certification/ Building Vibration/Technical Advisory/Research Review/Vibration and Noise Education Lecture/Company of Noise and Vibration Engineers/Korea CBM/kcbm.kr


70 강제주파수는 고유주파수와 무엇이 다른가 소음과 진동분야에서 주파수의 원인별 구분



강제주파수는 고유주파수와 무엇이 다른가? (소음과 진동분야에서 주파수의 원인별 구분)

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통기타를 연주할 때, 악보코드에 맞추어 기타줄을 튕기면 6개의 각 선(현)들은 다른 음을 발생하더라도 코드에 맞게 특별한 음색을 보이는 하모닉 음이 발생한다. 기타음은 각 줄별로 독특하고 소리의 높낮이가 서로 다르다. 이 이유를 알기위해 약간의 상식을 갖고 잘 살펴보면 튕기고 있는 기타줄의 길이와 기타줄의 종류 그리고 기타줄이 조여있는 정도에 따라서 소리가 '고유하게 다르다'는 것을 이해 할 수 있다.

반면에, 선풍기를 작동시키면 발생하는 진동, 자동차의 엑셀을 밟을 때마다 변동하는 RPM(분당 회전수)은 위의 기타줄에서 발생하는 고유한 특성과는 다르다. 즉, 이 것은 새롭게 생성되는 것, '강제로 만들어 내는 것'이며 반면에 기타줄은 원래 가지고 있었던 것, 쉽게 말하자면 손으로 튕기지 않으면 소리가 아예 처음부터 발생하지 않는다는 것과의 차이이다.

강제주파수(Forced frequency)

어떤 힘을 가하면 고유주파수와 강제주파수는 각각 모두 발생하지만 강제주파수는 만들어 생성된 값이고 고유주파수는 원래부터 있던 값이다. 이 두 개의 주파수가 ........

All copyright 한국CBM written by BISOPE , vs72@naver.com, 070-4388-0415, www.kCBM.kr

https://blog.naver.com/vs72

키워드

#공진, #고유주파수, #강제주파수, #RPM, #harmonic, #하모닉, #주파수분석, #공진분석, #스펙트럼분석, #FFT, #온라인모니터링, #진동모니터링, #소음모니터링, #응력모니터링, #진동센서, #3축진동, #진동소음교육


2023년 3월 15일 수요일

BISOPE series 31 Relation between type of vibration sensor and unit of ...


BISOPE series 31- Relation between type of vibration sensor and unit of amplitude (displacement, velocity, acceleration) Vibration measurement and evaluation

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If the desired 'unit' of vibration is selected as a result for the evaluation, the next step is to select an appropriate 'sensor'. First of all, it is necessary to check whether contact attachment is possible at the location to be measured... or whether the attachment method is appropriate. For example, in the case of high frequency (more than 5000Hz), the magnetic attachment method is not appropriate, and if you want to measure the behavior of an axis, it is difficult to use a contact sensor. Also, if you try to measure the speed and measure 5 Hz using a coin type speed sensor, you will get an amplified error signal. This is because the characteristics of each sensor are different depending on the amplitude band, frequency band, resonance band, etc.

 

Selection of displacement, velocity, and acceleration sensors such as amplitude units

Since the output voltage or current is proportional to each unit, the selection of the unit is not very different from the selection of the sensor. Sensors mainly used for diagnosing and monitoring equipment

 

1. Eddy current type displacement sensor (Proximity) that directly measures the behavior of a shaft supported by a sleeve bearing in a non-contact manner.

2. Accelerometer, which propagates shaft vibration to rolling bearing and measures it indirectly by contact method outside the bearing housing (indirectly transmitted to the housing by impact of the bearing connected to the shaft)

3. There is a velocity transducer that works without power.

However, among these, the speed sensor is very precise, but has a weakness limited to the range of 10 to 1000 Hz because it has a natural frequency in the upper and lower frequencies, which is why displacement sensors and acceleration sensors are widely used. (If it is out of this frequency range, an erroneous or amplified value is output.)

A sensor (transducer) is one of the components of a system that is mainly used by companies that use sensors to research, diagnose or manufacture monitoring equipment. Since the manufacturer has selected a sensor that fits a specific principle, the manufacturer has accumulated a lot of engineering grounds for this. In many cases, the level of engineering is considerably deeper than that of academia because it must be required and the reliability of the measurement needs to be verified.

Above all, this principle can be considered as the most basic sensor selection method. The reason why a displacement sensor is called a displacement sensor and an acceleration sensor is called an acceleration sensor is that each sensor generates an electrical output 'proportional to the amplitude unit'. It's because you do it. For example, since the value converted to displacement by outputting acceleration vibration with an acceleration sensor and integrating twice is not very accurate (especially when it is not a sine wave), it is better to measure acceleration vibration with an acceleration sensor, and displacement vibration It is basic to measure with a displacement sensor. However, there are cases where it is absolutely necessary to evaluate the health of a machine or the vibration of a building with the 'velocity' value, which is used as the most evaluation unit in academia and industry, so this only allows integration from the acceleration sensor once. Because the speed sensor isn't cool...

All copyright  korea CBM  written by BISOPE , vs72@naver.com, 070-4388-0415,  www.kCBM.kr


69 진동 센서의 종류와 진폭 단위와의 관련성 변위, 속도, 가속도 진동측정과 평가


진동 센서의 종류와 진폭 단위와의 관련성 (변위, 속도, 가속도) 진동측정과 평가 v2

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평가를 위해서 결과로 원하는 진동의 '단위'가 선택되었다면 그 다음으로는 적절한 '센서'를 선택해야 한다. 우선 측정하고자 하는 위치에 접촉부착이 가능한지... 또는 부착방법이 적절한지...를 확인해야 한다. 간단히 예를들어서 만약에 고주파(5000Hz이상)일 경우에는 자석식의 부착방법은 적절하지 못하며 축의 거동을 측정하고 싶었다면 접촉식센서로는 곤란하다. 또한 속도를 측정하려 했는데 동전식 속도센서를 사용하여 5Hz를측정한다면 증폭된 오류신호를 얻게 된다. 이러한 이유는 센서를 선택함에 있어 각 센서의 특성이 진폭대역, 주파수대역, 공진대역 등에 따라 각각 다르기 때문이다

진폭단위와 같은 변위, 속도, 가속도 센서의 선택

각 단위별로 출력전압 또는 전류가 비례하므로 단위의 선택은 센서의 선택과 크게 다르지 않다. 설비를 진단하고 상태를 감시하는 용도로 주로 사용되는 센서는

1. 슬리브베어링으로 지지된 축(shaft)의 거동을 비접촉으로 직접 측정하는 Eddy current방식의 변위센서(Proximity).

2. 구름베어링으로 축의 진동이 전파되어 베어링하우징 외부에서, 접촉방식으로 간접 측정하는(축에 연결된 베어링의 충격으로 하우징에 간접 전달되는) 가속도센서(Accelerometer)

3. 전원이 필요 없이 작동하는 속도센서(Velocity transducer)가 있다.

그러나 이중에서 ....................

All copyright 한국CBM(주) written by BISOPE , vs72@naver.com, 070-4388-0415,

관련 Tag

#진동의 단위, #진폭단위, #변위 #속도 #가속도, #rms, #주파수, #진동측정, #진동분석, #주파수분석, #진동소음교육, #공진분석, #resonance, #공진측정, #모니터링, #원격모니터링