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Adash 4900 Vibrio III, Руководство пользователя

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Adash 4900 Vibrio III Скачать руководство пользователя страница 37

ADASH Ltd. 

 

Adash 4900 – Vibrio III

 

 

 

 

 

37

Example.

 

We are going to show the analysis procedure on a signal obtained on a seating of an inlet 
transmission shaft with the speed frequency 25 Hz (1500 rpm) and with a gear with 65 teeth. So called 
tooth frequency can be obtained by simple multiplication of the shaft revolution frequency (in Hz) by 
the number of teeth. 
 

 

 

f

GMF = 

f

speed

 

*

 z

 

 

 

f

GMF

 

  gear mesh frequency 

f

speed

 

speed frequency 

z

 

number of teeth 

 
In our example the tooth frequency is 1625 Hz (so approx. 1,6 kHz). 
 
What are the possibilities? 

 

Condition 1: 

 

 

The transmission is OK

 and tooth frequency of 1,6 kHz slightly increases vibrations in the first two 

frequency ranges. 
 

Condition 2:

 

 

 
Vibrations are concentrated in the last frequency range 5 – 16 kHz, the vibrations in the last area are 
the same as in the area, where the tooth frequency shows itself - 

bearing failure 

Содержание 4900 Vibrio III

Страница 1: ... display of two measured values External piezoelectric accelerometer with 100 mV g sensitivity Overload indicator sensor fault and cable fault indicators Possibility of connecting headphones for listening of vibration Built in torch Simple control by three buttons Ref No 240709 PCE Americas Inc 711 Commerce Way Suite 8 Jupiter FL 33458 USA From outside US 1 Tel 561 320 9162 Fax 561 320 9176 info p...

Страница 2: ...ions 13 ISO 10816 limit values 14 Classification according to machine type nominal power or shaft height 14 Classification according to foundation 14 Evaluation ranges 14 Classification of vibration values for machines groups 1 and 3 15 Classification of vibration values for machines groups 2 and 4 15 Values setting in A4900 Vibrio III unit 15 Quick Start 16 Preparation of Measurement Point 16 Put...

Страница 3: ...ror 30 Measurement Error 31 How to evaluate the failure 32 Overall RMS values 32 Overall PEAK values 33 Spectrum 200 Hz Detection of Looseness 33 Time signal for bearing condition evaluation 34 Vibrations on frequency range gearboxes bearings 36 FASIT Expert System 39 Specifications Adash 4900 Vibrio III 40 ...

Страница 4: ...ic allows checking the condition of all your machinery You will be informed early about potential failure before the machine get damage and you will be able to order only real specific required maintenance instead of expensive overhauls The periodical measurements will allow you to keep your machines in good health You always ask before the decision to buy new instruments what unit is the best for...

Страница 5: ...led incorrectly then there would be a high signal value immediately This value will remain stable for some time the bearing will be able to withstand it but then there will be a fast increase and destruction of the bearing This short bearing life can take hours days weeks or even months 3 Reliability of the diagnostics will never be 100 There will always be defects which develop in time shorter th...

Страница 6: ...e unstable because measurements have significant variety of values The similar effects occur for bearing condition measurements You can measure RMS value the total energy in signal or PEAK value the highest peak in signal We can use both types for evaluation just have to realize of advantages and disadvantages RMS measurement advantages stable and well repeatable time trends are well readable disa...

Страница 7: ...MENT from the top Measurement Points The measurement location must enable repeatable measurements under the same conditions as the previous measurement Also the direction of sensor radial axial for rotated machines is important That is why you we should determine measurement points on the machine The typical machine together with the measurement points in the picture For the measurement in radial ...

Страница 8: ...ce made of a magnetic stainless steel They are fixed to chosen points with special glue which ensures a perfect transmission of the high frequency vibrations The pad is covered with a plastic cover which is removed only for the measurement Another advantage of the cover is that when the machine is painted your measurement point is preserved The paint would devalue the pad It is sufficient to coars...

Страница 9: ...ern world The opposite is true Analyses of gears and low speed bearings e g in paper mills gain better quality by using the listening method The listening can easily be done by any maintenance person without deeper knowledge of diagnostics If there is a defective bearing then distinct rumbling sound is audible in the headphones If the bearing is OK then you can hear only a weak noise HEADPHONES WA...

Страница 10: ...nstrument case contains measuring instrument A4900 Vibrio III vibration sensor accelerometer magnetic base for vibration sensor coiled cable to connect vibration sensor headphones measuring tip for putting manual pressure on vibration sensor 1 5V alkaline batteries Fig Adash 4900 Vibrio III with accessories ...

Страница 11: ...wer this instrument use only alkaline or rechargeable NiCd NiMH batteries Regular carbon zinc batteries are not suitable Ignoring any of the recommendations mentioned below may cause failure of the instrument Handling voltage higher then 24 V can cause an accident WARNING Use correct battery polarity Incorrect polarity will cause destruction of the instrument HEADPHONES WARNING Listen at moderate ...

Страница 12: ... of the machine The corresponding colors are taken from traffic semaphore green amber and red GOOD state is the space up to the yellow line that means operation without restriction The space above yellow but under red line is an ALERT state Possible to operate the machine but have to be more checked It s necessary to determine the source of worse condition and plan repair for instance change the b...

Страница 13: ...ent determines acceptable vibration limits depending on machine speed 0 0 1 0 2 0 3 0 4 0 5 0 6 0 0 500 1000 1500 2000 2500 3000 3500 4000 speed RPM Vel 10 1000Hz mm s RMS 0 0 04 0 08 0 12 0 16 0 2 0 24 Vel 10 1000Hz ips RMS 0 0 0 5 1 0 1 5 2 0 2 5 3 0 3 5 0 1000 2000 3000 4000 5000 6000 7000 8000 speed RPM Acc 5k 16kHz g RMS ...

Страница 14: ...ines include pumps with multi vane impellers and integrated drivers Group 2 and 4 ISO Group 2 and 4 classifications define the following type of machinery Medium sized machines and electrical machines with a shaft height between 160 and 315 mm These machines are normally equipped with rolling element bearings but may use sleeve bearings and operate at speeds above 600 RPM These machines include pu...

Страница 15: ...d R24 1 4 A B 2 8 B C 4 5 C D Flexible F24 2 3 A B 4 5 B C 7 1 C D Values setting in A4900 Vibrio III unit It s possible to set up these values directly in the unit Then the measured values are displayed in traffic light colors You can choose Adash limits recommended or 10 816 limits Setting up is in menu under the mode SETUP see instrument operation Colored marks according 10 816 are range A and ...

Страница 16: ...t It should also be flat so a sensor would not wobble The best is to use a measurement base which is glued on a machine It has a perfect finish plastic cover and is made from magnetic stainless steel This will enable you to perform the measurements on the machine at any time under the same conditions This measurement repeatability means that you will be able to compare the values well To attach th...

Страница 17: ...on signal we need to plug in the vibration sensor with ICP power The plugged in sensor must be a standard accelerometer with 100 mV g sensitivity The instrument is equipped by its own source of ICP power for connected sensor The sensor needs to be connected at the right input plug by a supplied cable Fig The instrument with a sensor connected ...

Страница 18: ...f the machine condition Instrument is looking for speed in the frequency spectrum 200Hz range It is assumed that most of the vibration energy is located on the speed frequency If the instrument finds significant energy level on one frequency that means in very narrow band then this frequency is labelled as the speed frequency From this description is clear that the speed has not to be found always...

Страница 19: ...he Misalignment the clutch icon Correspondent faults horizontal bars are in middle On the right bottom corner you find the rolling bearing icon The vertical bar displays the bearing condition The Stroboscope The build in stroboscope inside the A4900 Vibrio III represents the unique innovation in the handheld vibration analyzer field We use the high lighting LED technology which low power consumpti...

Страница 20: ...0 Vibrio III 20 The Torch You sometimes need to inspect or read the dark corners In that time you are lucky with A4900 Vibrio III because this instrument has built in torch in front panel See the Menu chapter for details ...

Страница 21: ...e instrument then a display will show an instrument Logo If the batteries are weak the VIBRIO sign is bordered in red Fig Switching on with Fig Switching on with Fig Switching off weak batteries The instrument is switched off by pressing and holding the same button for a longer time Before the instrument switches of the sign POWER OFF lights on the display slowly goes out and the instrument switch...

Страница 22: ...he status goes under 20 the remaining energy shows in red if it is insufficient the symbol is red and the instrument switches itself off Battery status symbol 100 approx 50 under 20 just before switching off Using of Headphones The instrument is equipped by a 0 5 W amplifier for connecting of headphones and listening to a measured signal We can connect the headphones by a stereo 3 5 mm jack marked...

Страница 23: ...tons Measurement Methods Screens Overall RMS values Measurement of RMS vibration values in the ranges 10 Hz 1000 Hz in mm s 5 kHz 16 kHz in g with estimated value of machine speed frequency Based on the speed and vibration values the machine condition and a colour of the displayed value green amber red is determined Overall PEAK values Measurement of peak vibration values in the ranges 10 Hz 1000 ...

Страница 24: ...ibration size Time signal for roller bearing diagnosis Measuring of time signal and vibrations in the range 5 kHz 16 kHz in g Displays actual measured time signal and gENV value Vibrations in frequency ranges gearbox bearing Measurement of RMS vibration values in the ranges 0 5 kHz 16 kHz in g 1 5 kHz 16 kHz in g 5 kHz 16 kHz in g Fasit expert system The FASIT screen It displays the severity level...

Страница 25: ... is loaded from the memory and displayed together with the message set Push arrows it changes the value of speed with the step 250 RPM When the correct speed or the value near the correct speed is defined push Enter button for confirmation If no pushbutton is used for approx 4 seconds then the displayed value is accepted The word set is changed to MAN then This word informs all the time the user t...

Страница 26: ... of a velocity signal mm s vs ips ESC Return to the measuring screen If the error is detected e g SENSOR ERROR then some item are not available Move between items by pressing buttons Select item by pressing button Use ESC for return from Menu Fig Instrument MENU 0 Fig Meaning of the buttons Fig Instrument MENU in error stage LIGHT In LIGHT mode it s possible to use instrument like the torch Select...

Страница 27: ...imum volume is reached the symbol will become orange otherwise the amount of yellow filling shows the actual volume If the headphones are off the symbol is grey Next press of the button returns the instrument back to the measurement mode Switched off cca 50 Maximum Fig Volume adjustment Fig Displayed volume During the instrument is switched on or off the range is changed the sensor is connected or...

Страница 28: ...oose requested function using arrows and confirm by Enter SPEED Switch on ON or switch off OFF automatic determination of revolutions function ALARMS Standards setup Alert limits amber color and Danger red color will be defined See Standards for vibration measurements chapter ...

Страница 29: ... machine symbol F13 in this case If Adash standard is chosen nothing is displayed UNITS Vibration speed unit can be chosen here mm s millimeters per second and ips inch per second are available Device remembers chosen unit even after switch off ESC Return to the MENU screen ...

Страница 30: ...error signifies incorrect connection of a sensor unsuitable sensor type broken cable etc Overload Error If an input signal is too strong higher than 12V peak and the instrument cannot process it the overload error is displayed The instrument is not capable of measuring this signal ...

Страница 31: ...ak in communication between measuring and display boards inside of the instrument this measurement initialisation error is displayed MEAS INIT If you see this error it means that the instrument is malfunctioning and we recommend to send it to the manufacturer for a check ...

Страница 32: ... which is excited by a condition of bearing This condition is related to time wear of the bearing bad lubrication with new bearings as well incorrect installation with new bearings as well abrading of bearing SPEED The machine speed is displayed at the bottom part of the screen if it is available RPM means revolutions per minute The instrument performs automatic determination of machine revolution...

Страница 33: ... value of such shock is hidden in a value which contains all other information about vibrations i e noise from possible abrading wrong lubrication and overloading To simplify the RMS is an average value of all vibration values achieved in certain time If a large peak value one shock appears in this time period it will be lost in the final recalculation of all the values This practically means that...

Страница 34: ...for bearing condition evaluation The time signal of bearing vibrations is displayed gENV value is under the time signal envelope modulated signal see Methods for ball bearing condition diagnostics chapter Caution the time signal is displayed as a direct record not after envelope modulation Look at three basic screens for easy work with this function Undamaged bearing This bearing generates a low a...

Страница 35: ...ger amplitude then previous case You can clearly see different bigger range of the graph 1 0 g Damaged bearing There are clearly visible shocks caused by a rolling element coming across the damage like pitting or crack here The shocks repeat themselves regularly The range of the graph is different again 2 0 g in this case ...

Страница 36: ...load Attention Please note that the ranges overlap They all have the upper frequency 16 kHz What does it mean for analysis The following examples should help you to understand their significance All values are the same All vibrations are in the last range If they were in the lower ranges also the highest range would have to have a lower value In the first two ranges the value is the same the last ...

Страница 37: ...y in Hz by the number of teeth fGMF fspeed z fGMF gear mesh frequency fspeed speed frequency z number of teeth In our example the tooth frequency is 1625 Hz so approx 1 6 kHz What are the possibilities Condition 1 The transmission is OK and tooth frequency of 1 6 kHz slightly increases vibrations in the first two frequency ranges Condition 2 Vibrations are concentrated in the last frequency range ...

Страница 38: ...quipment tied to the mentioned machine In case of multiple geared transmissions however these can be also the tooth frequencies of the second or third transmission gear Here we would not be able to do without a detailed analysis using an instrument with possibility of the spectrum analysis measurement The measurements on the screen No 6 can also be used in diagnostics of condition of low speed rol...

Страница 39: ...unit evaluates the severity of 3 sources which are the most occurred in the practise the Unbalance the circle with heavy spot icon the Looseness the shoe icon the Misalignment the clutch icon Correspondent faults horizontal bars are in middle On the right bottom corner you find the rolling bearing icon The vertical bar displays the bearing condition The meaning of Machine and Bearing bars was desc...

Страница 40: ...ctions LED stroboscope 0 17 Hz 300 Hz 10 RPM 18000 RPM LED torch Output 1x AC signal 8 Ω 0 5 W for external headphones signal listening Power 2x1 5V AA size alkaline batteries or 2x1 2V NiMH AA size rechargeable batteries Dimensions 150 x 60 x 35 mm Weight 350 g including batteries without cable sensor and magnet 540 g including batteries cable sensor and magnet Accessories vibration sensor coiled...

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