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PRÜFTECHNIK VIBXPERT Balancing, Operating Instructions Manual

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PRÜFTECHNIK VIBXPERT Balancing Operating Instructions Manual Download Page 16

2-8

VIBXPERT Balancing 11.2010

After completing the preparatory activities, ensure the following:

• The balancing RPM should lie as close as possible to the

operating RPM. If this is not possible due to high vibration
values, start at a lower RPM and approach the operating RPM
step-by-step in several balancing runs.

• Pay attention to potential resonance points and, if there is any

doubt, perform a coast down measurement!

• The RPM must remain constant during a balancing run! Otherwi-

se, the balancing run must be restarted.

• The rotor must reach operating temperaure during the measure-

ment (e.g. if the rotor works in a hot air stream).

• Often the static imbalance is dominant at vibration values above

10 mm/s. First, compensate this using 1-plane balancing before
proceeding with 2-plane balancing.

• Before starting the initial balancing run, check again that all

measurement components have been correctly installed.

• If a machine setup is used for the balancing procedure, check the

specified parameters. Incorrect rotor data may result in the
calculation of excessive trial weights under certain circum-
stances!

Balancing: Preparations

Note

Summary of Contents for VIBXPERT Balancing

Page 1: ...hope that you are happy with our product If you have any suggestions for improving this product or this instruction manual please let us know PRÜFTECHNIK Condition Monitoring Fax 49 89 99616 300 eMail info pruftechnik com VIBXPERT FFT Data Collector Signal Analyzer Balancing Operating Instructions ...

Page 2: ...e under no circumstances may the publisher be held liable for direct or indirect damage of any kind resulting from use of the product or the manual even if the publisher has expressly indicated the potential for occurrence of such damage The publisher assumes no liability for any product defects This warranty and liability limitation applies to all distributors and sales partners as well The trade...

Page 3: ...bine all mounted weights into a single new weight If you do not wish to attach a balancing weight to the rotor VIBXPERT will calculate the mass that should be milled from the rotor And just think VIBXPERT even grows to meet your future require ments The latest analysis and diagnostic functions are added on a regular basis and made available as an update This ensures that you are always have the mo...

Page 4: ... plane A and plane B 2 15 Trial run 2 16 Trim run 2 16 Saving the result 2 16 Evaluation of the data 2 17 Combining balancing weights 2 18 Options for balancing 2 19 Checking the measurement setting 2 19 Changing the correction mode 2 19 Fixed location 2 19 Fixed weight 2 20 Measuring tape 2 20 Removing the balancing weight 2 21 Checking functions 2 21 Entering the balancing radius and rotor mass ...

Page 5: ... reciprocating machines VIBXPERT can be used without any restrictions for the balancing of rigid rotors Elastic soft rotors may only be balanced with VIB XPERT at the resonant frequency 25 by an experienced user The measurement instrument and its accessories may only be operated by authorized personnel PRÜFTECHNIK Condition Monitoring assumes no responsibility for any damage arising from improper ...

Page 6: ...le regulations Before the first measurement initial run it is important to ensure that the preparatory activities have been carried out correctly and completely In addition to the assembly of measurement components particular attention must be paid to the correct input of parameters in the machine setup If an incorrect rotor mass is entered a trial weight that is too large may be calculated as a r...

Page 7: ...ical trigger sensor Transducer set for balancing with 2 channel instrument VIB 5 386 HW VIB 3 306 Reflective tape 10 mm VIB 5 432 2 9 Cable for trigger sensor 2 9 m VIB 6 631 Laser optical trigger sensor VIB 6 632 Bracket for laser optical trigger sensor Transducer set for balancing with 2 channel instrument on low speed machines VIB 5 388 HW VIB 3 306 Reflective tape 10 mm VIB 5 432 2 9 Cable for...

Page 8: ... of the balancing module VIB 5 386 FM see below Click on Device Setup in the start screen Click on Registration in the Device Setup screen see below Click on the Balancing not registered in the Registration screen and enter the registration password in the text editor Registration is now complete and the new operating mode now appears on the start screen Device Setup Registration Registering Balan...

Page 9: ... the rotor will cause this mass to immediately move downwards This process is called roll off Balancing Introduction If this rotor is now turned with the balancing RPM a centrifugal force is caused perpendicular to the rotational axis by the displacement of the center of gravity A static imbalance has to be corrected using 1 plane balancing because the planes of imbalance and center of gravity coi...

Page 10: ...nation of a static imblance and a couple imbalance and is usually compensated in two planes Basically the consideration of whether to carry out balancing in one or two planes depends on the specific machine situation i e on the balancing behavior of the rotor and the vibration behavior of the machine Simultaneous balancing in two planes is quicker and more precise than successive balancing measure...

Page 11: ...igid rotors are balanced using this method A rigid rotor mainly exhibits proportional vibration behavior if the balancing weight and angle change In the case of fixed rotational speed weaknesses or resonances in the mounting have no influence on the vibration behavior If the machine rotates at a variable speed it frequently exhibits different vibration behavior for each revolution and therefore ha...

Page 12: ...akes it possible to determine the measurement location with the highest vibration values where the sensors should be mounted see p 2 5 RPM Measures the rotor RPM If a machine setup is used for balancing this parameter is required in order to calculate the resulting centrifugal forces Phase measurement one two planes Records the amplitude and phase angle of the RPM synchronous vibration signal This...

Page 13: ...ons are transferred via the outer ring of a bearing in a radial direction Thus mount the transducer on the side horizontal or on the top of the bearing vertical Find suitable measurement locations by searching for positions with the highest vibration values using a hand held probe The transducer should be attached as close as possible to the bearing Prevent signal attenuation due to excessively lo...

Page 14: ...g the methods described here 4 Attach reference mark on the shaft for the trigger sensor Use reflective tape VIB 3 306 and place this perpendicular to the direction of rotation TIP Place the mark as close as possible to the groove of the adjusting spring The mark should be easy to find and the measurement results can be reproduced more easily Angle convention the angular reference mark lies at 0 t...

Page 15: ...rk while the machine is at a standstill As far as possible the laser beam should be perpendicular to the shaft surface and shaft axis Trigger sensor assembly R R F ESC MENU HELP Trigger Bracket VIB 6 632 Vibration transducer on the magnetic adapter VIB 6 142R VIB 3 420 Reflective tape VIB 3 306 Laser Trigger Sensor VIB 6 631 Trigger cable VIB 5 432 2 9 6 Connect the vibration transducer and the tr...

Page 16: ...ing run Otherwi se the balancing run must be restarted The rotor must reach operating temperaure during the measure ment e g if the rotor works in a hot air stream Often the static imbalance is dominant at vibration values above 10 mm s First compensate this using 1 plane balancing before proceeding with 2 plane balancing Before starting the initial balancing run check again that all measurement c...

Page 17: ...ollowing two setup menus can also be changed during a balancing run Display setup display settings see p 2 24 Tools balancing related settings and parameters that can be changed during a balancing run see p 2 19ff Display In each balancing run two main screens appear The data screen shows the balancing weights and their positions on the rotor in the upper half of the screen The lower half contains...

Page 18: ...ht is calculated 2 Trim to N Trim Trim runs for reduction of rotor imbalance The initial imbalance pointer represents the starting point of the balancing procedure Zoom VIBXPERT automatically scales the display range with respect to the last two balancing runs To magnify the view press the button repeatedly If the initial imbalance moves out of the display range the maximum range is also given as ...

Page 19: ...tive Use different radii option inactive Activating the balancing mode 1 Switch on VIBXPERT 2 Click on the Balancing icon in the start screen Selecting the task 1 Open the 1 plane tab 2 Highlight the rotor graphic which corresponds to the rotor type 3 Check and change the current measurement task beforehand if necessary MENU Task Manager Setup 4 Click on the rotor graphic to open the measurement s...

Page 20: ...n 1 Move the joystick to the right to open the data screen for the trial run 2 Enter the mass and fixing angle for the trial weight Click on the mass or angle field under the rotor graphic The active field is highlighted in black Enter the respective value in the number editor and confirm the entry with MENU OK 3 Move the joystick to the right until the next screen appears If the trial mass is app...

Page 21: ...n change the mass accordingly and repeat the trial run Trim run 1 Move the joystick to the right to close the measurement screen of the trial run and to open the data screen of the first trim run Depending on whether the trial weight resulted in an improvement or not it can be left on the rotor or taken off Respond to the resulting prompt in the screen accordingly 2 Attach the recommended mass at ...

Page 22: ...working with Machine Setup the calculated balancing quality is the criterion for terminat ing the balancing procedure A smiley appears in the measurement screen if the balancing quality has reached the tolerance range Undoing balancing runs If the measurement results worsen after a trim run you can return to a run that was acceptable and continue balancing with different weights from there Navigat...

Page 23: ...n Recommendation for trial weight in plane B measurement in plane A and plane B with trial weight in plane B 2 Balancing run Recommendation for balancing weight in plane A and plane B measurement in plane A and plane B N Balancing run Determining the measurement plane balancing plane A 1 Activate the balancing mode and open the 2 planes tab 2 Click on the rotor graphic which corresponds to the rot...

Page 24: ... data screen of the trim run see next page Move the joystick to the right to mark the input fields of the series Continue the trim run until the residual imbalance is within the tolerance range Saving the result Press the MENU button in the data screen Click on Save to open the text editor Enter a name Finally press the MENU button and click on OK AA Result in plane A AB Result in plane B trial we...

Page 25: ...k on Data The Data View screen appears Here you can combine the balancing weights to a single weight and display the following information MACHINE NAME Name of the machine setup if used DATE TIME Date and time of the last balancing run SPEED Shaft rotational speed that is selected in the machine setup BALANCE QUALITY Balance quality after the last balancing run RESIDUAL UNBALANCE Imbalance after t...

Page 26: ...ulated balancing weight appears in the list in the line for the next balancing run All combined runs are marked with a sum symbol Σ Then press the MENU button and click on OK to accept the combination of the balancing weights Before continuing with the next balancing run remove the weights that were already attached and attach the newly calculated balancing weight to the rotor Balancing Evaluation...

Page 27: ...ar position Press the MENU button in the data screen and click on Tools The following correction modes are available additionally Fixed location Fixed weight Meas tape Fixed location To attach the balancing weight only at specific positions on the rotor e g on the blade of a ventilator select the Fixed location correction mode Then enter the Number of locations on the rotor VIBXPERT calculates two...

Page 28: ...stance on the outer surface of the rotor is calculated in millimeters or inches from the trigger mark 0 position and measured counter to the direction of rotation Place a tape measure around the rotor and place the balancing weight at the specified position i e length The distance of the balancing weight from the rotational axis is the balancing radius This is usually smaller than the outer radius...

Page 29: ...appropriate error message appears if the RPM varies excessively CHECKING BAD INFLUENCE The change of the imbalance indicator is checked if the change is too large too small an appropriate message appears Return to the previous balancing run and reduce or increase the weight used RECALCULATING THE COEFFICIENT The coefficient for calculating the balancing weight can be taken over from the trial run ...

Page 30: ...ce coefficient After the test run VIBXPERT calculates the influence coefficient that is used to calculate the balancing weights If you wish to use the influence coefficient from a previous balancing measurement you have the following options 1 Manual entry via the number editor In the Tools menu click on Value mm s g angle First enter the amplitude Press the MENU button and click on OK Enter the a...

Page 31: ...ne This option is only available when balancing in one plane with vibration monitoring in a control plane The monitoring option is activated in the machine setup When balancing in one plane the vibration usually increases in the control plane When this option is activated VIBXPERT calculates the balancing weights in such a way that the vibration is minimized in both planes Generally this option is...

Page 32: ...NG PLOT MODE The imbalance pointers of the two planes can be displayed separately in two polar plots or together in one polar plot AMPLITUDE The vibration amplitude can be specified in RMS 0 p or p p STEP LIST DETAIL Select detailed if you would like all balancing runs to appear in the data and measurement screen The short option only shows the first run initial imbalance and the last completed ba...

Page 33: ...ge the report configuration Select the printer Press the MENU button and click on Print The balancing related report content is found on the Measure Info tab POLAR PLOT The balancing report contains a polar plot showing the completed balancing steps STEP LIST DETAIL The balancing report contains all balancing steps detailed or only the first and last steps short BALANCE QUALITY IMPROVEMENT The bal...

Page 34: ...ined balancing quality To create a machine setup proceed as follows Mark a rotor type in the selection screen see p 2 11 Press the MENU button and click on Task manager Mark the Machine setup field Press the MENU button and click on New or on Edit PLANES One Two Number of balancing planes cannot be changed because the rotor type is selected in the selection screen CORRECTION MODE Free fixed locati...

Page 35: ...th the same excitation a machine oscillates more strongly on a flexible foundation than on a rigid foundation The permissible vibration limit values can therefore be higher on a flexible foundation The balancing weights are smaller for a flexible foundation than for a rigid foundation USE DIFFERENT RADII Yes No the trial weights can be attached at a different radius than the balancing weights RADI...

Page 36: ...he selected number of averages in the measurement setup This option works only in combination with the Checking stability option p 2 21 CHECK BAD INFLUENCE Yes No see Checking functions p 2 21 RECALCULATING COEFFICIENT Yes No see Checking functions p 2 21 AUTO TRIAL MASS Yes No VIBXPERT calculates a trial weight from the machine data and recommends this in the trial run If this option is deactivat...

Page 37: ...f measurements see above The number of time synchronous averages is either RPM dependent user defined or unrestricted Auto Time synchronous number of averages is a function of the rpm Manual Time synchronous number of averages can be entered max 254 Unrestricted Each individual measurement is averaged with the preceding individual measurement The longer the measurement takes the more stabile the f...

Page 38: ...isplay In the measurement and data screen the balancing plane is marked with a plus sign plane A in the example below Reducing vibration in the balancing and control planes Vibration in the control plane generally increases with each balancing run since VIBXPERT calculates the balancing weights for the balanc ing plane To reduce the vibrations in both planes as far as possible you can include the ...

Page 39: ...k gear rigidly mounted high speed 4 cylinder diesel engines 100 Crank gear rigidly mounted high speed diesel motors with six and more cylinders 40 Automobile wheels rims wheelsets drive shaft crank gear elastical ly mounted high speed four stroke engines with six and more cylinders 16 Crank gear components of automobile truck and locomotive engines crank gear of six and more cylinder engines with ...

Page 40: ...ientation of the trigger optics for the reference mark Initializing The measurement amplifier is adjusted Autorange Speed fluctuates Results can be influenced The RPM variation is too large or deviates too much from the measured RPM of the preceding balancing run Wait until the machine has reached the balancing RPM before starting the measure ment Vibration pointer unstable The magnitude and or th...

Page 41: ...ial weight must be increased Restart is recommended 1 plane balancing If the vibration values increase and the balancing weights increase from one balancing run to the next no further improvement can be expected The entire balance measurement must be restarted Masses combined Remove previously attached masses The previously attached balancing weights are added together vectorially to form a single...

Page 42: ...n which the interrupted balancing procedure was started e g 1 plane The recovery file is labeled with a warning symbol Click on the recovery file to open the recovery dialog box It shows information on when the emergency storage took place and the number of balancing steps see below Click on Restore to open the file and continue the balancing procedure or to save the data properly Click on Discard...

Page 43: ...3 5 VIBXPERT Balancing 11 2010 empty page ...

Page 44: ...Productive maintenance technology Printed in Germany VIB 9 806 11 2010 0G VIBXPERT OMNITREND are registered trademarks of PRÜF TECHNIK AG Contents subject ot change without further notice particularly in the interest of further technical developement Reproduction in any form whatever only upon express written consent of PRÜFTECHNIK AG Copyright 2004 by PRÜFTECHNIK AG ...

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