BISOPE series 39 Gear frequency 5 Causes of gear vibration external an...

BISOPE series 39- Gear frequency-5- Causes of gear vibration (external and internal defects)

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The gearbox is one of the mechanical elements (belt, chain, etc.) that transmits power to the driven part by changing gears, and its biggest feature compared to other similar elements is that it can transmit strong torque. Therefore, places that require strong torque at low speeds with high-speed power are mostly places that receive strong loads. The gearbox is particularly used as a reducer for cement traction and crushing, tire crushing and extrusion, and frequent power transmission of trains. On the other hand, gearboxes used for high-pressure discharge in gas production are sometimes used for rotational change as gearboxes. If you look again, you can see that the gearbox is never a mechanical element that can be used alone. So vibration occurs.

Causes of gear box vibration

All Gear Boxes are connected to other machines. Therefore, it is heavily influenced by it. However, there are also problems with the gear itself, for example, gear vibration occurs due to misalignment of the pitch line, eccentricity, or inconsistency between tooth intervals. Internal defects of the Gearbox itself and external defects affecting the Gearbox are summarized as follows.

 ​https://blog.naver.com/vs72

 

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

#gear vibration, #gearbox, #bearing vibration, #sideband, #GMF, #gear #meshing #frequency, #gearbox with misalignment, #electrical vibration, #harmonic, #vibration measurement, #resonance analysis, # Vibration education, #resonance measurement, #frequency analysis#vibration diagnosis, #facility diagnosis

BISOPE series 37 Difference between shaft vibration and casing vibratio...

BISOPE series 37- Difference between shaft vibration and casing vibration(shaft vibration monitoring, bearing housing; casing vibration monitoring)

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If a dangerous state of a rotating machine is identified in advance or the machine suddenly breaks down, production is disrupted and huge asset losses occur. Therefore, in order to check the maintenance time while looking at the status (CBM), 'monitoring' must be performed and a 'monitoring system' must be installed or operated. As a monitoring method, the vibration of the facility is measured regularly in the field and sensing is performed by installing a continuous monitoring online system. But what is 'monitoring measurement technology'? The monitoring measurement technology is also divided into two parts as above, which are 'shaft vibration and casing vibration'. As for this distinction, even among those who specialize in vibration research, if you have not experienced the general field facility management method, you may not know the exact difference. This is very common in the current industrial field, but let's look at the direct differences in monitoring measurement technology that can never be confirmed theoretically.

 

Shaft & Casing, Housing vibration monitoring (shaft displacement vibration and bearing housing vibration)

 

Vibration in a rotating machine starts when the shaft rotates and excitation force (centrifugal force) is generated. Therefore, it is best to directly measure shaft vibration (shaft vibration measurement method), but this method has technical limitations. Therefore, a method of measuring where the shaft vibration is transmitted to the bearing housing or casing is often used, and this is commonly referred to as 'bearing housing vibration' or 'casing vibration'. This difference was sorted out.

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This data is very realistic and it is the result confirmed in the actual domestic industrial field, but it can be subjective and biased, so please refer to it.

 

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

 

#bearing vibration, #sleeve bearing, #metal bearing defect, #journal bearing, #vibration defect, #whirl, #bearing friction, #subharmonic, #non synchronous, #transient tolerance, #vibration diagnosis, #vibration analysis, #vibration Measurement, #frequency analysis, #facility diagnosis, #vibration education, #resonance analysis, #resonance measurement, #CBM, #vibration monitoring

BISOPE series 20 Why is there a difference in the speed of sound in sol...

BISOPE series 20- Why is there a difference in the speed of sound in solids and gases?

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Why is there a difference in the speed of sound in solids and gases?

 

The speed at which sound waves propagate through a medium is the definition of sound speed. The medium itself does not move, it is the propagation speed of the phase of the sound wave. When looking at the wavelength as the origin, sound waves in a narrow sense propagate through the fluid as longitudinal waves (penetrating the medium in the propagation direction), and their speed varies depending on the conditions of the medium such as temperature and humidity and the type of medium.

 

Change in momentum and rate of volume change

 

​The propagation speed of longitudinal waves is determined by the mechanical properties of the medium. Considering the change in momentum of the fluid moving in the piston (vt) with a certain cross-sectional area (A), it can be viewed as the product of the mass (ρvtA) of the fluid and the change in velocity (u). On the other hand, when the pressure increase Δp in the moving fluid is obtained, the initial volume Avt of the fluid in motion is decreased by Aut, so from the definition of the bulk modulus (;- pressure change/volume change rate)

 

Velocity of sound, modulus of elasticity - https://blog.naver.com/vs72

 

is established At this time, 'B' is the bulk modulus, and when the medium is a fluid, it corresponds to the volume modulus (volume change rate), and when the medium is a solid, it corresponds to the Young's modulus. Since it is larger than the bulk modulus of , the velocity in the medium of longitudinal waves is ultimately influenced by the difference in the velocity of sound by the difference in the volume modulus rather than the difference in the density. V solid > V liquid > V gas !

 

Difference in speed of sound - https://blog.naver.com/vs72

 

What is the difference between the speed of sound and the speed of particles?

 

As the speed at which sound waves propagate through an elastic medium, the formula is the same as above, and among them, the speed of sound in the air is expressed conveniently and c=20.06√T in relation to temperature.

On the other hand, particle velocity (v) is the vibration velocity of a medium that transmits sound waves, and when it is assumed as a plane wave, it can be expressed as v=p/ρc. (T: absolute temperature, p: pressure, ρ: density, c: speed of sound)

 

 

 

Wavelength, particle velocity - https://blog.naver.com/vs72

 

speed of sound in different media

​All copyright Korea CBM Co., Ltd. written by BISOPE

 

#vibration measurement, #vibration analysis, #frequency analysis, #resonance measurement, #resonance analysis, #3-axis vibration, #accelerometer, #fft, #bearing vibration, #vibration noise education, #equipment diagnosis, #cbm, #bearing vibration , #building vibration, #gear movement, #visope, #looseness, #environmental vibration, #rotating machine, #vibration education, #vibration monitoring, #balancing, #volume modulus, #sonic velocity, #noise and vibration

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

#vibration measurement, #vibration analysis, #frequency analysis, #resonance measurement, #resonance analysis, #3-axis vibration, #accelerometer, #fft, #bearing vibration, #vibration noise education, #equipment diagnosis, #cbm, #bearing vibration , #building vibration, #gear movement, #visope, #looseness, #environmental vibration, #rotating machine, #vibration education, #vibration monitoring, #balancing, #volume modulus, #sonic velocity, #noise and vibration