tag:blogger.com,1999:blog-65108692218821919752024-03-13T14:22:25.485-07:00An Introduction To Balancing | Cemb Hofmann UKAnonymoushttp://www.blogger.com/profile/02324188011445948438noreply@blogger.comBlogger20125tag:blogger.com,1999:blog-6510869221882191975.post-64815275486691096982015-05-08T03:02:00.002-07:002015-05-08T03:07:26.421-07:00Latest Software Success From Balancing Expert Cemb Hofmann UK <br />
The latest development at Cemb Hofmann UK is the intutive software which has been released for balancing flexible rotors.<br />
<br />
This software will help users to achieve optimum results and the best possible balancing - through the use of pre-set balancing planes (2 or 3 planes) within only one measuring cycle.<br />
<br />
During the same measurement, multiple readers are performed automatically in sequence and at varying speeds.<br />
<br />
By comparing these measurements with the coefficients obtained during calibration stage, users can utilise reliable data and balance the rotor with only one measuring cycle.<br />
<br />
This proceedure will stop automatically for the safety of both machine and operator if the rotor has excessively high unbalance. If this situation arises, the software will save the correction values which were measured at lower speed before stopping. Because of this functionality, the operator will be able to conduct a pre-balancing cycle, enabling the reduction of initial unbalance and making final measurement possible at maximum speed.<br />
<br />
Using a pre-balanced shaft, calibration is obtained and the rotor is able to run at the maximum defined speed. Should this software not be enabled, the balancing machine will work as a standard hard bearing machine with manual speed adjustment.<br />
<br />
Catch up on more of the <a href="http://www.cembhofmann.co.uk/html/balancing-news.html" target="_blank">latest balancing news</a> from Cemb Hofmann UK today or call our experienced sales team on 0161 872 3123 for more information.<br />
<br />Anonymoushttp://www.blogger.com/profile/02324188011445948438noreply@blogger.com0tag:blogger.com,1999:blog-6510869221882191975.post-34540742678026386782014-03-24T05:22:00.003-07:002014-03-24T05:25:03.899-07:00Portable Vibration Measurement | The new N600 instrument<br />
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<a href="http://2.bp.blogspot.com/-QDW4DEvHPQo/UzAjc9jEClI/AAAAAAAAANk/w1xUXJNsHNQ/s1600/foto_pag2.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" src="http://2.bp.blogspot.com/-QDW4DEvHPQo/UzAjc9jEClI/AAAAAAAAANk/w1xUXJNsHNQ/s1600/foto_pag2.jpg" height="133" width="200" /></a></div>
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<span style="font-family: "Swiss721BT-Light","sans-serif"; mso-ansi-language: EN-GB; mso-bidi-font-family: Swiss721BT-Light;"><span style="font-family: Times New Roman;">CEMB’s range of portable equipment for vibration
measurement and analysis, balancing and predictive maintenance has been
enhanced with the new N600 instrument.</span></span></div>
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<span style="font-family: "Swiss721BT-Light","sans-serif"; mso-ansi-language: EN-GB; mso-bidi-font-family: Swiss721BT-Light;"><span style="font-family: Times New Roman;"></span></span> </div>
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<span style="font-family: "Swiss721BT-Light","sans-serif"; mso-ansi-language: EN-GB; mso-bidi-font-family: Swiss721BT-Light;"><span style="font-family: Times New Roman;">Equipped with an ample, backlit, high resolution LCD
colour screen, N600 can be used in all types of lighting conditions.<o:p></o:p></span></span></div>
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<span style="font-family: "Swiss721BT-Light","sans-serif"; mso-ansi-language: EN-GB; mso-bidi-font-family: Swiss721BT-Light;"><span style="font-family: Times New Roman;">Ease of use, calculation power and intuitive methods
for the setting/presentation of measurements and graphs are the main features
of this instrument. <o:p></o:p></span></span></div>
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<span style="font-family: "Swiss721BT-Light","sans-serif"; mso-ansi-language: EN-GB; mso-bidi-font-family: Swiss721BT-Light;"><span style="font-family: Times New Roman;">The analysis functions provide the information needed
for machine diagnosis and diagnosis of the condition of the bearings so the
most appropriate maintenance work can be identified.<o:p></o:p></span></span></div>
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<span style="font-family: "Swiss721BT-Light","sans-serif"; mso-ansi-language: EN-GB; mso-bidi-font-family: Swiss721BT-Light;"><span style="font-family: Times New Roman;">The balancing function can be used to balance any type
of rotating body on one or more plane irrespective of size and weight. <o:p></o:p></span></span></div>
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<span style="font-family: "Swiss721BT-Light","sans-serif"; mso-ansi-language: EN-GB; mso-bidi-font-family: Swiss721BT-Light;"><span style="font-family: Times New Roman;">The vibration trend over time, spectral analysis and
Bode plot, which are essential tools for defining the corrective action needed
with extreme precision, are all visible directly on the screen.<o:p></o:p></span></span></div>
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<span style="font-family: "Swiss721BT-Light","sans-serif"; mso-ansi-language: EN-GB; mso-bidi-font-family: Swiss721BT-Light;"><span style="font-family: Times New Roman;">All of the readings taken can be saved in a database
using sophisticated software for effective and rational organisation of
predictive maintenance.<o:p></o:p></span></span></div>
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The equipment is supplied with standard accessories (2 accelerometers with a heavy-duty spiral cable, Hi-Speed 250,000 cpm photocell, USB stick, angle rule) sufficient for performing all of the main functions. Various optional accessories are also available (other types of sensors, extensions, Bluetooth printer) for when the equipment needs to be used in special conditions.<br />
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The software package, which can be installed on a PC, can perform data acquisition route creation (Route Manager) functions and provides diagnostics tools (Advanced Diagnostic Software).Three different levels are available to meet all requirements: storage, detailed analysis, diagnostics, measurement comparisons, trends, spectrums, orbits.<br />
<br />
<strong>LEVEL 1 Basic</strong><br />
<br />
• Multilingual interface<br />
• Trend data<br />
• Route management<br />
• Data export option<br />
• Zoom<br />
<br />
<strong>LEVEL 2 Standard</strong><br />
<br />
All Level 1 functions plus:<br />
• FFT analysis<br />
• Harmonic cursor<br />
• List of peak values<br />
• Waveform<br />
<br />
<strong>LEVEL 3 Expert</strong><br />
<br />
All Level 1 and 2 functions plus:<br />
• Waterfall analysis<br />
• Orbit analysis<br />
• Bode plot<br />
• Nyquist plot<br />
• Statistical analysis<br />
<br />
N600 VERSATILE AND COMPLETE<br />
<br />
<strong>Standard accessories:</strong><br />
<br />
• No. 2 accelerometer transducers 100mV/g<br />
• No. 2 transducer connection cables L 2.5 m<br />
• No. 1 heavy duty spiral cable L 2 m<br />
• No. 2 magnetic bases Ø 25 mm<br />
• No. 2 probes<br />
• No. 1 250,000 Cpm Hi-speed, laser photocell complete with upright and magnetic base<br />
• No. 1 roll of reflecting tape<br />
• No. 1 USB stick for data transfer<br />
• Angle rule<br />
• Battery charger<br />
• Universal plug<br />
• Case complete with carry strap<br />
• Manual<br />
<br />
<strong>Optional accessories:</strong><br />
<br />
• Bluetooth printer<br />
• Protective cover<br />
• Velocity transducer complete with lead and magnetic base<br />
• Proximity sensor complete with upright, lead and magnetic base<br />
• Connection cable for transducers L 5 m<br />
• 10 m-long extension cable for transducers<br />
• 10 m-long extension cable for photocell<br />
• CEMB ADS software for data storage and management<br />
<br />
TECHNICAL DATA<br />
<br />
<strong>Functions:</strong><br />
<br />
• Measurement of the overall vibration value (acceleration, velocity, displacement)<br />
• Vibration phase measurement<br />
• Analysis of vibration in the frequency range<br />
• Monitoring overall vibration in relation to time or velocity (Bode plot)<br />
• Balancing of rotating bodies in operating conditions on 1 or 2 planes<br />
• Waveform<br />
<br />
<strong>Measurement types</strong><br />
<strong></strong><br />
• Effective value (RMS)<br />
• Peak value (Pk)<br />
• Peak-to-peak value (PP)<br />
<br />
<strong>Units of measurement</strong><br />
<strong></strong><br />
• Acceleration: [g]<br />
• Velocity: [mm/s] or [inch/s]<br />
• Displacement: [μm] or [mils]<br />
• Frequency: [Hz] or [Cpm]<br />
<br />
<strong>Input</strong><br />
<strong></strong><br />
• 2 independent and simultaneous measuring channels (accelerometer, velocimeter, non-contact, any signal max. 5V-PP)<br />
• 1 photocell channel (velocity and angle reference)<br />
• 2 USB ports for data transfer<br />
<br />
<strong>Vibrometer function</strong><br />
<strong></strong><br />
• Measurement of the overall vibration value in predefined frequency bands<br />
(10-1000Hz; 3-300Hz; 10-10000Hz) or bands defined by the user (within the range of 3-20000Hz)<br />
• Measurement of 1x fundamental vibration value and phase<br />
• Measurement of rotating body velocity<br />
FFT Function (Analysis in frequency)<br />
• FFT analysis (manual/trigger)<br />
• Maximum settable frequency (25; 100; 500; 1000Hz; 2.5; 5; 10; 15kHz)<br />
• Resolution (100; 200; 400; 800; 1600; 3200 lines)<br />
• Number of averages: from 1 to 16<br />
• List of main peak values<br />
<br />
<strong>Monitor – Data Logger functions</strong><br />
<br />
• Recording and display of overall vibration trend over time<br />
• Storage and display of vibration trend and phase when rotation velocity changes.<br />
<br />
<strong>Balancing function</strong><br />
<strong></strong><br />
• Number of correction planes: from 1 to 2<br />
• Graphic indicator of measurement stability<br />
• Balancing procedure, guided step by step, with option for editing and intermediate changes<br />
• Vectorial breakdown of the unbalance<br />
• Correction by adding or removing material<br />
<br />
<strong>General characteristics</strong><br />
<br />
• Display: 7” colour LED-backlit TFT LCD<br />
• A/D converter: 24 bit resolution<br />
• Dimensions: approx. 225 x 200 x 50 mm<br />
• Weight: 1.4 kg<br />
<br />
<strong>Operating conditions</strong><br />
<br />
• Temperature: from -10° to +50° C<br />
• Air humidity: from 0 to 95% without condensate <br />
<br />
<strong>Power supply</strong><br />
<br />
• Rechargeable 6Ah Lithium battery<br />
• Charging time: < 5 hours (when battery is fully discharged)<br />
• Power supply-battery charger for 100-240 V, 50/60 Hz (24 V, 1.5 A)<br />
• Battery life: > 8 hours based on typical use<br />
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Anonymoushttp://www.blogger.com/profile/02324188011445948438noreply@blogger.com0tag:blogger.com,1999:blog-6510869221882191975.post-28553977563768537632014-02-09T09:24:00.003-08:002014-02-09T10:06:17.516-08:00Find Us At MACH 2014 Stand 5025 Hall 5MACH 2014 is almost upon us and as the UK's largest manufacturing technology event, we are delighted to be exhibiting again this year on Stand 5025 in Hall 5.<br />
<br />
Running from 7th to 14th April, this is a truly unmissable week for anyone with an interest in innovative technology especially as it has just been revealed that the exhibition will be opened by none other than the world land speed record holder Richard Noble - Project Director for the <a class="g-profile" href="https://plus.google.com/111575340946063461043" target="_blank">+BLOODHOUND SSC - 1,000 mph car</a><br />
<br />
With companies such as <a class="g-profile" href="https://plus.google.com/114407749178854370205" target="_blank">+Bruderer UK Ltd</a> celebrating a "world first" at the show and prestigious exhibitors such as <a class="g-profile" href="https://plus.google.com/107972112998695636029" target="_blank">+Airbus+</a> and <a class="g-profile" href="https://plus.google.com/103459961688865434182" target="_blank">+Rolls-Royce Motor Cars</a> it comes as no surprise that registration figures are already up by 25%!<br />
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<h3>
Our Balancing Machines</h3>
We will be exhibiting a number of our balancing machines at MACH 2014 including the ZB5 dynamic balancing machine and the VTB15/M vertical tool balancing machine.<br />
<br />
<h3>
ZB5 Dynamic Balancing Machine</h3>
Purposely designed for rotors weighing 0.2 to 10 Kg, the<a href="http://www.cembhofmann.co.uk/html/z5tc.html" target="_blank"> ZB5 dynamic balancing machine</a> can be table mounted or supplied with a rigid base. Rotors are loaded on anti-friction pedestals or roller bearings, adjustable according to the size and type of rotor to be balanced. <br />
<br />
In order to reduce operating time the Z5 is supplied complete with automatic indexing, dual rotation and a unique belt drive system that can be either over or under-slung.<br />
<br />
<h3>
B11 Measuring Instrumentation</h3>
<br />
The B11 is an unbalance-measuring instrument for hard or soft bearing balancing machines, either with vertical or horizontal axis and designed to solve the most demanding problems related to measurement and correction of unbalance. <br />
<br />
The unit can be used with complex automated solutions, PLC and computer networks. The software offers user friendly correction programs for adding and removing material including:<br />
<br />
Radial & axial drilling<br />
Radial & axial milling<br />
Adding weights<br />
Vector partitioning<br />
<br />
<h3>
VTB15/M Vertical Tool Balancing Machine </h3>
<br />
The <a href="http://www.cembhofmann.co.uk/html/vtb15.html" target="_blank">VTB 15/M dynamic balancing machine</a> is designed to measure the unbalance in tools and tool holders for high-speed machine applications. The machine will accept all ISO, BT, HSK and ABS attachments and incorporates a program for eliminating mechanical eccentricity of the mounting tool.<br />
<br />
<h3>
Portable and Condition Monitoring Equipment</h3>
<br />
The N500 is a user friendly multi-functional analyser, designed for measurement of vibrations, FFT vibration analysis, monitoring total vibration against time or variation in machine speed, as well as balancing rotating equipment under service conditions on 1 or 2 planes.<br />
<br />
Come and visit Cemb Hofmann UK at Stand 5025 at MACH 2014.<br />
<br />
To reach our expert balancing team, call Cemb Hofmann UK today on 0161 872 3123 or visit our <a href="http://www.cembhofmann.co.uk/" target="_blank">Website</a>.<br />
<br />Anonymoushttp://www.blogger.com/profile/02324188011445948438noreply@blogger.com0tag:blogger.com,1999:blog-6510869221882191975.post-1753216258668516382013-12-15T04:33:00.000-08:002013-12-15T04:33:01.010-08:00Balancing Tolerances and Balancing PlanesLet us consider a rotor having a pure couple unbalance of 15 gr mm placed on two different planes with 100 mm distance:<br />
<br />
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<a href="http://1.bp.blogspot.com/-vH4iBIXmQxw/Uq2Y_W90HTI/AAAAAAAAAMo/aCipXfvtqNQ/s1600/Titan+15-Dec+11.56.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://1.bp.blogspot.com/-vH4iBIXmQxw/Uq2Y_W90HTI/AAAAAAAAAMo/aCipXfvtqNQ/s1600/Titan+15-Dec+11.56.jpg" /></a></div>
<br />
<br />
Taking as reference the previous figure, it is clear that, depending on the position (distance ) of the two selected balancing planes, the measured unbalance which is to be corrected varies (30, 15, 10 gr mm). <br />
<br />If the acceptable balancing value per plane is 15 gr mm, then the rotor is considered within tolerance only if the two balancing planes are placed on the supporting position or at a distance of 100 mm; for shorter distances balancing planes the rotor is no more within tolerance.<br />
<br />Now, a rotor should be considered properly balanced (within tolerance ) indifferently of the two selected balancing planes. <br />
<br />As a consequence a correct unbalance tolerance can be specified in two ways by defining:<br />
<br />
<br />
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<a href="http://1.bp.blogspot.com/-EvZ3tBMmJkg/Uq2cRBW9dnI/AAAAAAAAAM0/WWJ2IO5X4mc/s1600/Titan+15-Dec+12.1048.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://1.bp.blogspot.com/-EvZ3tBMmJkg/Uq2cRBW9dnI/AAAAAAAAAM0/WWJ2IO5X4mc/s1600/Titan+15-Dec+12.1048.jpg" /></a></div>
<br />
<br />
<br />Defining a limit value (balancing tolerance) for the unbalance referred to the bearing journal directly gives a limitation to the rotating forces which exert on it. <br />
<br />This is particularly useful, because an acceptable residual unbalance calculated with the above mentioned rule, is valid whichever are the two selected balancing planes.<br />
<br />API 612 e 613 standards use this rule and calculate the residual acceptable unbalance with the following formula.<br />
<br />
<br />
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<img border="0" height="114" src="http://4.bp.blogspot.com/-q7POop4S4Y8/Uq2eiXtL0yI/AAAAAAAAANA/kkQkeFAUVNQ/s320/Titan+15-Dec+12.20.jpg" width="320" /></div>
<br />
<br />
<br />To avoid any confusion between the actual balancing planes (where we act ) and the two planes where the unbalance tolerance is specified.<br />
<br />To specify always, in a clear way, the two planes where the acceptable residual unbalance is valid.<br />
<br />
With the use of a modern microprocessor measuring unit, it is possible to specify the tolerance on the two balancing planes or on the two rotor supports.<br />
<br />To specify the unbalance tolerance on the two rotor supports, it is sufficient to set the parameters A = C = 0 and the parameter B = Supports distance <br />
<br />
<br />
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<img border="0" height="73" src="http://1.bp.blogspot.com/-PDcgzMfnD5Y/Uq2gJzw6RVI/AAAAAAAAANM/ZcUqVCfZV0Q/s320/Titan+15-Dec+12.25.jpg" width="320" /></div>
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<br />
Read more about <a href="http://www.cembhofmann.co.uk/html/resource-centre.html" target="_blank">balancing</a> at the <a href="http://www.cembhofmann.co.uk/" target="_blank">Cemb Hofmann UK</a> site or call our expert balancing team today on 0161 872 3123.<br />
Anonymoushttp://www.blogger.com/profile/02324188011445948438noreply@blogger.com0tag:blogger.com,1999:blog-6510869221882191975.post-74941660786548437902013-09-24T02:09:00.000-07:002013-09-24T02:12:42.970-07:00Static / Couple Unbalance with Narrow Balancing Planes<br />
When balancing on narrow planes, it is necessary to distinguish between <a href="http://www.cembhofmann.co.uk/html/static-balancing-machines.html" target="_blank">static</a> and couple unbalance, because the two types of unbalances have a different effects on the supports.<br />
<br />
<h3>
Example 1: Pure static unbalance</h3>
<br />
The following figure shows the effects ,on the rotor supports ,generated by a <a href="http://www.cembhofmann.co.uk/html/static-balancing-machines.html" target="_blank">static unbalance</a> applied on a over hang pump impeller.<br />
<br />
Support loads are calculated according to the laws of static M = 0 ; R = 0 (The conditions for equilibrium are that the momentum and the resultant of all forces are zero).<br />
<br />
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<a href="http://1.bp.blogspot.com/-7hOY64EfZyw/UkFTL7Wa_bI/AAAAAAAAALk/4wtrtYA-SCY/s1600/Titan+24-Sep+09.5346.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img alt="Pure Static Unbalance Diagram" border="0" src="http://1.bp.blogspot.com/-7hOY64EfZyw/UkFTL7Wa_bI/AAAAAAAAALk/4wtrtYA-SCY/s1600/Titan+24-Sep+09.5346.jpg" title="" /></a></div>
<br />
<br />
<h3>
Example 2: Couple unbalance</h3>
<br />
The next figure shows the effect generated by a couple unbalance on the supports of an over hang impeller.<br />
<br />
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<br />
The effect of couple unbalance is reduced by the ratio of the arms.<br />
<br />
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="http://4.bp.blogspot.com/-1jJ4NSFwBCI/UkFVNLItfeI/AAAAAAAAAMA/M8-y8QXvfIQ/s1600/Titan+24-Sep+10.02.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://4.bp.blogspot.com/-1jJ4NSFwBCI/UkFVNLItfeI/AAAAAAAAAMA/M8-y8QXvfIQ/s1600/Titan+24-Sep+10.02.jpg" /></a></div>
<br />
<br />
For the above mentioned reason, different values for static and couple unbalances are specified. <br />
<br />
<strong>For instance</strong>: <br />
Static unbalance tolerance = 1 gr mm<br />
Dynamic unbalance tolerance (couple) = 4 gr mm per plane<br />
<br />
<strong>For instance:</strong><br />
For axial fun impeller (width 30÷40 mm and an external diameter of 300÷400 mm) the normal required tolerance on the static unbalance is 30÷50 gr mm while a couple unbalance of 100÷200 gr mm is accepted.<br />
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<br />Anonymoushttp://www.blogger.com/profile/02324188011445948438noreply@blogger.com0tag:blogger.com,1999:blog-6510869221882191975.post-41190632126509240832013-09-16T12:01:00.005-07:002013-09-24T02:13:41.980-07:00Allocation of Permissible Residual Unbalance To Each Correction Plane According to ISO 1940/1<br />
ISO 1940/1 standards calculate the total acceptable unbalance of a rotor (static unbalance) referred to the plane (rotor section) containing the centre of mass.<br />
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The acceptable residual unbalance on the two balancing planes (dynamic unbalance) is calculated taking care of the position of the centre of mass with regard to the position of the correction planes.<br />
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<a href="http://1.bp.blogspot.com/-syMPbty8c3Q/UjdTDhIw2GI/AAAAAAAAALU/-DL_zW1PRF4/s1600/Titan+16-Sep+19.50.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img alt="Balancing Diagram" border="0" height="400" src="http://1.bp.blogspot.com/-syMPbty8c3Q/UjdTDhIw2GI/AAAAAAAAALU/-DL_zW1PRF4/s400/Titan+16-Sep+19.50.jpg" title="" width="391" /></a></div>
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<span class="formola"><span style="font-size: large; mso-bidi-font-size: 10.0pt;"><em><sub><o:p>Note:</o:p></sub></em></span></span></div>
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<span class="formola"><span style="font-size: large; mso-bidi-font-size: 10.0pt;"><em><sub><o:p>If the calculated value for U1 , U2 is lower than 0.3 Ut the value 0.3 Ut is used ; if the calculated value is bigger than 0.7 Ut the value to be used is 0.7 Ut,</o:p></sub></em></span></span></div>
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<span style="clear: left; float: left; font-size: x-small; margin-bottom: 1em; margin-right: 1em;"><img alt="Balancing Diagram from Cemb Hofmann UK" border="0" height="322" src="http://2.bp.blogspot.com/-lw90G-FsBvs/UjdNQrlTp1I/AAAAAAAAAKY/U4e8flCWMKg/s400/Titan+16-Sep+19.2540.jpg" title="" width="400" /></span></div>
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<img border="0" height="270" src="http://1.bp.blogspot.com/-j12hFJzAO3o/UjdRbhPfpEI/AAAAAAAAALI/cMfoKS2Eyz8/s320/Titan+16-Sep+19.4344.jpg" width="320" /></div>
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A frequent application of the above mentioned rules happens with pump and fun impellers (over hang mounted.)<br />
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<img border="0" height="320" src="http://1.bp.blogspot.com/-NqCBMIyZj-I/UjdPSw4yDfI/AAAAAAAAAK0/lwMt9XMEjsg/s320/Titan+16-Sep+19.3442.jpg" width="274" /></div>
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<img border="0" height="82" src="http://4.bp.blogspot.com/-OUCq9u68kes/UjdPodr1tdI/AAAAAAAAAK8/qYtoWnh8nrQ/s320/Titan+16-Sep+19.3643.jpg" width="320" /></div>
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For more information about balancing visit <a href="http://www.cembhofmann.co.uk/" target="_blank">Cemb Hofmann UK</a> today or call our expert team on 0161 872 3123.<br />
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Anonymoushttp://www.blogger.com/profile/02324188011445948438noreply@blogger.com0tag:blogger.com,1999:blog-6510869221882191975.post-75217129247412719742013-08-27T11:49:00.003-07:002013-09-24T02:11:40.367-07:00Balancing tolerances calculated according to the maximum admitted load on the bearings<br />
The goal of <a href="http://www.cembhofmann.co.uk/" target="_blank">balancing</a> is to reduce loads /vibrations on the supporting frames, in order to achieve an acceptable life. <br />
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The unbalance introduces internal couples and rotating forces on the bearings. As a consequence, the residual acceptable unbalance can be calculated by stating a maximum acceptable value for the rotating (centrifugal forces) generated by the unbalance in service conditions.<br />
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A possible rule is to state that the rotating force is kept below 10 percent of the static load.(USA navy standards)<br />
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<a href="http://1.bp.blogspot.com/-Gwxe4rOlxeo/UhzxMFm0YdI/AAAAAAAAAJg/-aSV5iwIaO0/s1600/Titan+27-Aug+19.3330.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://1.bp.blogspot.com/-Gwxe4rOlxeo/UhzxMFm0YdI/AAAAAAAAAJg/-aSV5iwIaO0/s1600/Titan+27-Aug+19.3330.jpg" /></a></div>
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<a href="http://2.bp.blogspot.com/-q_TVu9u6l9Y/Uhzzt8rFDsI/AAAAAAAAAJ8/jztbhJxfKsU/s1600/Titan+27-Aug+19.44.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img alt="Dynamic and static balancing machine expert" border="0" src="http://2.bp.blogspot.com/-q_TVu9u6l9Y/Uhzzt8rFDsI/AAAAAAAAAJ8/jztbhJxfKsU/s1600/Titan+27-Aug+19.44.jpg" title="" /></a></div>
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It is worth pointing out that according to API and to ISO standards, the accepted residual eccentricity (unbalance) varies with the relationship is linear while with the last rule (USA navy standards ) it varies with the inverse of the square of the speed (as the speed increases the accepted residual unbalance decreases rapidly.)<br />
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If you would like to speak with a balancing expert then call Cemb Hofmann UK today on 0161 872 3123 to discuss any area of <a href="http://www.cembhofmann.co.uk/" target="_blank">unbalance </a>that you may be experiencing with your rotating parts.<br />
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<br />Anonymoushttp://www.blogger.com/profile/02324188011445948438noreply@blogger.com0tag:blogger.com,1999:blog-6510869221882191975.post-31135214465013383562013-08-11T06:12:00.000-07:002013-08-11T06:12:01.272-07:00Balancing Tolerances according to API 610 Standards<br />The following formula is valid: <br />
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<a href="http://1.bp.blogspot.com/-6hLV-qLnE7Q/UgeG4jAUgZI/AAAAAAAAAIs/f5Ht5v3_TuI/s1600/Titan+11-Aug+13.4225.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://1.bp.blogspot.com/-6hLV-qLnE7Q/UgeG4jAUgZI/AAAAAAAAAIs/f5Ht5v3_TuI/s1600/Titan+11-Aug+13.4225.jpg" /></a></div>
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Where:<br /><br />
U [gr mm] = Admitted residual unbalance referred to the bearing journals<br />
<br />W [kg] = Static load on the considered bearing(mass)<br />
<br />N [RPM] = Maximum service speed<br />
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Modifying previous formula , we obtain:<br />
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<a href="http://1.bp.blogspot.com/-zrW3xFhaT0I/UgeHaWEjY-I/AAAAAAAAAI0/JvBOJhIMO6A/s1600/Titan+11-Aug+13.4427.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://1.bp.blogspot.com/-zrW3xFhaT0I/UgeHaWEjY-I/AAAAAAAAAI0/JvBOJhIMO6A/s1600/Titan+11-Aug+13.4427.jpg" /></a></div>
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<a href="http://1.bp.blogspot.com/-DH0qDg1-mkk/UgeHt5WdxsI/AAAAAAAAAI8/_m-aBIQEOrA/s1600/Titan+11-Aug+13.4628.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://1.bp.blogspot.com/-DH0qDg1-mkk/UgeHt5WdxsI/AAAAAAAAAI8/_m-aBIQEOrA/s1600/Titan+11-Aug+13.4628.jpg" /></a></div>
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The equivalent ISO formula is : <br />
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<a href="http://1.bp.blogspot.com/-o5F2KFqCIZo/UgeIBC9n9PI/AAAAAAAAAJE/l5ICYfc__5c/s1600/Titan+11-Aug+13.4729.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://1.bp.blogspot.com/-o5F2KFqCIZo/UgeIBC9n9PI/AAAAAAAAAJE/l5ICYfc__5c/s1600/Titan+11-Aug+13.4729.jpg" /></a></div>
<br /> Important notes:<br />
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1) Unbalance tolerance according to API standards is more severe than ISO grade G=1. It is 1,5 more precise and it seems sometimes not obtainable. <br />
<br />2) It is important to point out that the required tolerance, according to API standards, is referred to the bearing journals and not to the two balancing planes. (I will be blogging further about this later this month)<br />
<br />3) The unbalance tolerance measured in microns, (Eccentricity = unbalance per unit of mass) is related to the required mechanical precision , especially when adapters are necessary to mount the rotor on the machine spindle.(the used adapter shall have a mounting precision below the required tolerance <br />
<br />4) For balancing qualities equal to or below G 1 ISO, standard recommends to balance the rotor complete with its own bearings .(The eccentricity between the inside and the outside bearing race can be of the same level as the requested eccentricity).<br />
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I will be blogging again shortly to explore "Balancing tolerances calculated according to the maximum admitted load on the bearings".<br />
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In the meantime, feel free to contact Cemb Hofmann UK on 0161 872 3123 should you have any specific questions about balancing.<br />
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We specialise in dynamic and static balancing as well as the provision of an <a href="http://www.cembhofmann.co.uk/html/contract-balancing.html" target="_blank">outstanding sub contract dynamic balancing service</a> from Cemb Hofmann UK<br />
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As a manufacturer of some of the most <a href="http://www.cembhofmann.co.uk/" target="_blank">high precision and accurate balancing machines</a> on the market today, Cemb Hofmann UK is extremely well placed to offer advice on any area of unbalance - from industrial to agricultural and avionic.<br />
Anonymoushttp://www.blogger.com/profile/02324188011445948438noreply@blogger.com1tag:blogger.com,1999:blog-6510869221882191975.post-81531052723542521012013-07-31T06:52:00.001-07:002013-07-31T06:52:13.681-07:00Evaluation of the balancing quality G (The total residual unbalance is known)
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In the assumption that the total residual unbalance is known, it is possible to calculate the corresponding value for the balancing
quality G according to ISO standards 1940/1.</div>
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<o:p> </o:p></div>
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Example of calculation:</div>
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<o:p> </o:p></div>
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Rotor mass M [kg] = 6</div>
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Maximum service speed N [RPM] = 5000<o:p> </o:p></div>
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Total residual unbalance U [gr mm] = 180<o:p> </o:p></div>
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Total residual eccentricity E [<span style="font-family: Symbol; mso-ascii-font-family: "Times New Roman"; mso-char-type: symbol; mso-hansi-font-family: "Times New Roman"; mso-symbol-font-family: Symbol;"><span style="mso-char-type: symbol; mso-symbol-font-family: Symbol;">m</span></span>] = 180/6 = 30</div>
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<a href="http://1.bp.blogspot.com/-tXMw5Jmz_xI/UfkT-pLWdwI/AAAAAAAAAHA/zQtytpUyJ-w/s1600/Titan+31-Jul+14.4024.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://1.bp.blogspot.com/-tXMw5Jmz_xI/UfkT-pLWdwI/AAAAAAAAAHA/zQtytpUyJ-w/s1600/Titan+31-Jul+14.4024.jpg" /></a></div>
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<o:p></o:p> </div>
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<o:p><span style="font-size: x-small;"> </span></o:p><o:p><span style="font-size: x-small;"> </span></o:p><br />
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Using the diagram featured in my recent blog post entitled "Balance quality grades for various groups of representative rigid rotors" - two lines are drawn; one
line, normal to the x axis, passing through the maximum service speed value, (5000 in the example). The second line, normal to the y axis, passing through the
residual eccentricity (30 in the example).<o:p></o:p></div>
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The inclined line, passing through the intersection point
of the two drawn lines, defines the <a href="http://www.cembhofmann.co.uk/" target="_blank">balancing</a> quality (grade).<o:p> </o:p></div>
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As an option, the following formula can be used: <o:p></o:p></div>
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<o:p> </o:p><div class="separator" style="clear: both; text-align: center;">
<a href="http://3.bp.blogspot.com/-9kkRSs4oUGg/UfkUbnPaW0I/AAAAAAAAAHI/DteNWl7jvzo/s1600/Titan+31-Jul+14.4225.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://3.bp.blogspot.com/-9kkRSs4oUGg/UfkUbnPaW0I/AAAAAAAAAHI/DteNWl7jvzo/s1600/Titan+31-Jul+14.4225.jpg" /></a></div>
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If you would like to know more about any area of balancing - or have a specific issue of unbalance that you would like to discuss with an expert, please do not hesitate to pick up the phone and contact Cemb Hofmann UK today on <strong>0161 872 3123</strong> or visit our <a href="http://www.cembhofmann.co.uk/" target="_blank">Cemb Hofmann UK Website</a> now.<br />
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Cemb Hofmann is the UK specialist in <a href="http://www.cembhofmann.co.uk/html/static-balancing-machines.html" target="_blank">static</a> and <a href="http://www.cembhofmann.co.uk/html/dynamic-balancing-machines.html" target="_blank">dynamic</a> balancing - manufacturing high precision and highly accurate static and dynamic balancing machines as well as a highly acclaimed sub contract dynamic balancing service.<br />
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Anonymoushttp://www.blogger.com/profile/02324188011445948438noreply@blogger.com0tag:blogger.com,1999:blog-6510869221882191975.post-19242874368792192112013-07-16T05:23:00.002-07:002013-07-16T05:51:21.975-07:00Examples of calculation of residual unbalance according to ISO 1940/1 Standards for rigid rotors<br />
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Example Number 1: Fun
impeller<o:p> </o:p></h2>
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Maximum service speed = 1500 RPM </div>
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Mass M = 200 kg <br />
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Left, right side correction radius Rs = Rd = 800 mm <br />
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Balancing quality G = 6,3 <br />
<br />
From previous diagram we obtain: <br />
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Total acceptable residual eccentricity et = 40 m <br />
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Total acceptable residual unbalance Ut = M·e = 200 kg x 40 m = 8000 gr x mm <br />
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<em><span style="font-size: x-small;">Note: The acceptable unbalance per plane has been calculated by simply dividing by two the total acceptable unbalance; this operation is correct because the two balancing planes have almost the same distance from the centre of mass position, which is at the same time almost in the centre of the rotor.</span></em></div>
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Example Number 2: Turbine</h2>
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Maximum service speed = 3000 RPM</div>
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Rotor mass M = 500 kg</div>
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Left side balancing radius Rs = 500 mm</div>
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Right side balancing radius Rd = 400 mm</div>
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Balance quality G = 2,5</div>
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From previous diagram we obtain: </div>
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Total acceptable residual eccentricity et = 8u</div>
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<strong></strong><br />
Values within brackets are valid for the quality G = 1 (quality g 1 is nowadays commonly required for turbines )</span><br />
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Example Number Three: Impeller
of a centrifugal pump<o:p> </o:p></h2>
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Maximum service speed = 6000 RPM</div>
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Mass M = 10 kg</div>
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Balancing radius R = 100 mm</div>
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Required balancing quality G = 6.3</div>
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From previous diagram we obtain: <br />
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<span style="font-size: x-small;"><br /><span style="font-size: small;">Note: Since the impeller is thin (reduced axial dimensions ) it is balanced in one plane only ( Static balancing)</span><br />
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<span style="font-size: small;"></span> </span><br />
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Example Number 4: Tool holder dynamically balanced<o:p> </o:p></h2>
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The tool holder has a useful length L bigger than 2D (where D is the cone diameter ). <br />
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Considering its length it is advisable to balance it on two planes. <br />
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Maximum service speed = 24'000 RPM <br />
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Tool holder mass M = 5 kg <br />
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Correction radius on balancing plane 1 R1 40 mm <br />
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Correction radius on balancing plane 2 R2 20 mm<br />
<br />
Required balancing quality G = 2.5<br />
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(ISO standards specify quality G=2.5 for machine tools spindles and driving systems) <br />
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Total acceptable residual eccentricity E = 1 m <br />
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Total acceptable residual unbalance Ut = M·E = 5 kg x 1 m = 5 gr x mm</div>
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<o:p><span style="font-size: x-small;">Note: The total acceptable unbalance has been divided by two because we assumed that tool holder mass is more or less symmetrical with regard to the centre of mass position ,and that the two correction planes contain the centre of mass almost in the middle position.</span></o:p></div>
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Example Number 5: Tool holder balanced in one plane only</h2>
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Let us consider a tool holder which is to be balanced in one plane (static balancing).</div>
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Normally the tool holder is balanced in one plane only , if its length L is lower than 2D (D is cone diameter) </div>
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Maximum service speed = 12'000 RPM </div>
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Tool holder mass M = 1 kg </div>
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Balancing radius = 20 mm</div>
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Balancing quality G = 1</div>
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(ISO standards specify quality G 1 for grinding machine spindles) </div>
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Total acceptable eccentricity E = 2 m </div>
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Total acceptable residual unbalance Ut = M·E = 1 kg x 2 m = 2 gr x mm </div>
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Cemb Hofmann UK is the leading UK <a href="http://www.cembhofmann.co.uk/" target="_blank">Balancing expert</a> and offers not only high precision balancing machine sales but also a highly acclaimed sub contract dynamic balancing service. </div>
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For more information about any area of balancing, please visit the <a href="http://www.cembhofmann.co.uk/" target="_blank">Cemb Hofmann UK Website</a> or call us today on 0161 872 3123.</div>
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Anonymoushttp://www.blogger.com/profile/02324188011445948438noreply@blogger.com0tag:blogger.com,1999:blog-6510869221882191975.post-44959826320441413132013-06-19T01:23:00.000-07:002013-06-19T01:24:06.547-07:00Understanding Required Balancing Tolerances<br />
<br />
The following drawing defines the required balancing tolerance according to ISO 1940/1.standards:<br />
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<br />
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NOTE: The table in my previous blog defines the required balancing quality G according to each rotor type.<br />
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The maximum service speed is reported on the horizontal x axis , while the acceptable specific unbalance (acceptable unbalance per unit of mass or acceptable residual mass eccentricity ) is reported on the vertical y axis.<br />
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The following formula can be used instead of the previous diagram:<br />
<br />
Where: Et [] = total acceptable mass eccentricity<br />
N [RPM] = Maximum service rotor speed<br />
G [mm/s] = Balancing quality or grade<br />
Total residual accepted unbalance: U [gr∙mm] = Et∙M<br />
where: M [kg] = Rotor mass<br />
Total residual admitted unbalance in grams is where R [mm] is the compensation radius.<br />
<br />
This is all very technical stuff and most likely, only of interest to a very small number of people who enjoy the complexities of balancing as much as myself!<br />
<br />
If you would rather leave the formulae to the experts then why not have a chat with a balancing machine expert at <a href="http://www.cembhofmann.co.uk/" target="_blank">Cemb Hofmann UK</a>. <br />
<br />
Call us today on 0161 872 3123 and we will be delighted to assist you with whatever area of unbalance you are experiencing with your rotating parts.<br />
<br />
<br />
<br />Anonymoushttp://www.blogger.com/profile/02324188011445948438noreply@blogger.com0tag:blogger.com,1999:blog-6510869221882191975.post-90425579532561788142013-06-18T05:27:00.000-07:002013-06-18T05:27:09.216-07:00A Guide to Balance Qualilty Grades The chart below is designed to give an overview of the balance quality grades for various groups of representative rigid rotors.<br />
<br />Note: Some groups of rotors, not included in the official ISO table, are added and reported in Italic type form.<br />
<br />
Balancing quality grade is show in G mm/s<br />
<br />
-----------------------------------------------------------------------------------<br /><br /><strong>0,4</strong> Gyroscopes<br /> Spindles, discs and armatures of precision grinders<br /> <em> Textile fuses</em><br />
<br /><strong>1,0</strong> Small electric armatures with special requirements<br /> Tape recorder and phonograph (gramophone) drives, cine projectors<br /> Grinding machine drives<br /> <em>Turbines and Compressors with special requirements</em><br />
<br /><strong>2,5</strong> Gas and steam turbines, including marine main turbines (merchant service) <br /> Turbine driven pumps<br /> Rigid turbo generator rotors<br /> Turbo compressors<br /> <em>High speed compressors and aeronautic compressors</em> <br /> Medium and large electric armatures with special requeriments<br /> <em>High quality household electric armatures, dentist drills and textile components</em><br /> Small electric armatures not qualifying for one or both of the conditions specified <br />
for small electric armatures of balancing quality grade G 6,3<br /> Machine tool drive<br /> <em>Air conditioning fans for hospitals and concert halls<br /> High speed gears(over 1000 RPM) of marine turbines .</em> <br /> Computer memory drums and discs<br />
<br /><strong>6,3</strong> Small electric armatures, often mass produced, in vibration insensitive applications, and/or<br />
with vibration isolating mountings.<br /> Medium and large electric armatures (of electric motors having at least 80 mm shaft height )<br />
without special requirements<br /> Machine tool and general machinery parts<br /> Parts of process plant machines, Centrifuge drums, <em>decanters, washers<br /> Hydraulic machine rotors</em><br /> Fly wheels, Fans; Pump impellers <br /> Marine main tuebine gears (merchant service )<br /> Paper machinery rolls; print rolls<br /> Assembled aircraft gas turbine rotors<br /> Individual components of engines under special requirements<br />
<br />
<strong>16</strong> Drive shafts (propeller shafts, cardan shafts) with special requirements<br /> Parts of agricultural machinery, parts of crushing machines<br /> Individual components of engines (gasoline or diesel) for cars ,trucks and locomotives<br /> Crankshaft / drives of engines with six or more cylinders under special requirements<br /> <em> Low speed separators<br /> Light boat impellers)<br /> Motor bicycle and car wheels<br /> Normal transmission pulley<br /> Wood machine tools</em><br />
<em></em><br />
<strong>40</strong> Car wheels, wheel rims, wheel sets and drive shafts<br /> Crankshaft / drives of elastically mounted fast four cycle engines (gasoline or diesel ) with<br />
six or more cylinders (pistons speed greater than 9 m/s)<br /> Crankshaft /drives of engines of cars , trucks and locomotives<br />
<br />
We hope that you will find this information useful - please get in touch with the specialist balancing team at Cemb Hofmann UK on 0161 872 3123 should you have any queries regarding this table or any other aspect of balancing.<br />
<br />
Please visit our site: <a href="http://www.cembhofmann.co.uk/">www.cembhofmann.co.uk</a> for more information about balancing machines and sub contract balancing services.<br />
<br /><br />Anonymoushttp://www.blogger.com/profile/02324188011445948438noreply@blogger.com0tag:blogger.com,1999:blog-6510869221882191975.post-62956915006418666712013-06-10T05:26:00.000-07:002013-06-10T05:29:55.490-07:00Balancing TolerancesThe <a href="http://www.cembhofmann.co.uk/" target="_blank">balancing</a> of a rotating body has different goals:<br />
<br />
1) Reduced load on the bearings (low centrifugal forces)<br />
2) Long bearings life<br />
3) Acceptable vibration levels (a good vibration level does not create any problems to the comfort or to component life.<br />
<br />
From previous point 3 , it is clear that the optimum value for the residual unbalance can be evaluated in an experimental mode, by considering that:<br />
<br />
a) The inertia force generated by the unbalance can be calculated using the formula reported on paragrath 1.15<br />
<br />
b) On service vibrations, levels can be easily measured with a simple vibrometer.<br />
For each application an acceptable value for the admitted residual unbalance (which grants good performances ) can be defined.<br />
<br />
ISO 1940 standards gives a rule in order to calculate an acceptable residual unbalance, having following features:<br />
<br />
1) Gross unbalance deficiencies are avoided,<br />
2) Useless and excessive balancing works are avoided<br />
<br />
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<br />
<br />
<br />
Where: E = Mass eccentricity [microns]<br />
U = Unbalance [gr•mm]<br />
M = Rotor mass [kg]<br />
<br />
According to ISO 1940 standards, all rotors are classified (grouped), depending on their balancing requirements (look at following table). Balancing quality G is a number which defines the balancing accuracy required; for instance G = 2,5 means that a fine balancing is required, G = 6,3 means that a normal balancing is accepted.<br />
<br />
Please note that the measuring unit for G is mm/s, because this value represents the vibration speed assumed by the body rotating freely in the space at the real service speed.<br />
<br />
The same value of vibration speed ( G=mm/s) is achieved by the rotor, when it rotates mounted on a soft bearing machine at service speed.<br />
<br />
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<br />
<br />
Balancing can be a very complex subject and I would be delighted to hear from anyone experiencing unbalance who is in need of technical advice. <br />
<br />
Cemb Hofmann is the UK's leading specialist in balancing - from balancing machine sales to a world-class sub contract dynamic balancing service.<br />
<br />
Visit <a href="http://www.cembhofmann.co.uk/">www.cembhofmann.co.uk</a> today for more information or call us on 0161 872 3123 to speak to a member of our team today.<br />
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Anonymoushttp://www.blogger.com/profile/02324188011445948438noreply@blogger.com0tag:blogger.com,1999:blog-6510869221882191975.post-33389715325960651602013-05-14T06:19:00.000-07:002013-05-14T06:20:13.487-07:00The Common & Frequent Words of BalancingBalancing is a complex and tricky artform - producing a technical language that is riddled with certain phrases and words that would confuse many customers in need of balancing advice.<br />
<br />
Below is an explanation of two of the most common used terms.<br />
<strong></strong><br />
<strong><a href="http://www.cembhofmann.co.uk/html/static-balancing-machines.html" target="_blank">Static balancing</a></strong> : Unbalance measuring and correction is carried out in one plane only.<br />
<br />
<strong><a href="http://www.cembhofmann.co.uk/html/dynamic-balancing-machines.html" target="_blank">Dynamic balancing</a></strong> : Unbalance measuring and correction is carried out in two different planes.<br />
<br />
<strong>Correction planes</strong> : Is the section (plane) where unbalance correction is performed by adding or removing mass.<br />
<br />
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<a href="http://1.bp.blogspot.com/-KzaUpoc8MZc/UZI4t0oS4oI/AAAAAAAAAD0/mWBeId6GEN8/s1600/Titan+14-May+14.1312.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://1.bp.blogspot.com/-KzaUpoc8MZc/UZI4t0oS4oI/AAAAAAAAAD0/mWBeId6GEN8/s1600/Titan+14-May+14.1312.jpg" /></a></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="http://1.bp.blogspot.com/-_gnJRuMyLAg/UZI41WMCnBI/AAAAAAAAAD8/1hJbGVrhw1c/s1600/Titan+14-May+14.14.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img alt="static and dynamic balancing" border="0" height="149" src="http://1.bp.blogspot.com/-_gnJRuMyLAg/UZI41WMCnBI/AAAAAAAAAD8/1hJbGVrhw1c/s320/Titan+14-May+14.14.jpg" title="Static and Dynamic balancing from Cemb Hofmann UK" width="320" /></a></div>
<br />
<br />
At Cemb Hofmann we pride ourselves in the delivery of first class balancing services - from high quality machine sales to a world-class sub contract balancing service.<br />
<br />
To find out more visit <a href="http://www.cembhofmann.co.uk/">www.cembhofmann.co.uk</a> or call our team today on 0161 872 3123Anonymoushttp://www.blogger.com/profile/02324188011445948438noreply@blogger.com0tag:blogger.com,1999:blog-6510869221882191975.post-52063019067650955952013-05-14T05:45:00.002-07:002013-05-14T05:46:02.370-07:00Balancing Speed: A Comprehensive ExplanationThe unbalance of a rotor is caused by the radial distribution of its masses along its axis of rotation. <br />
<br />
The consequence is that if the rotor is rigid, and this means that the values and relative positions of its masses do not change, the unbalance does not change with the speed. In a rigid rotor the operating speed does not modify mass distribution and consequently has no influence on the unbalance.<br />
<br />
By adding a 20 gr mass at a defined radial position on a perfectly balanced disc an unbalance is generated. This unbalance does not change with the speed, it is just necessary to remove the added 20 gr mass independently of rotor speed.<br />
<br />
For rigid rotors the balancing speed does not need to be specified because it is related only to machine sensitivity and not to the rotor unbalance which is under measurement.<br />
<br />
Modern hard bearing <a href="http://www.cembhofmann.co.uk/" rel="" target="_blank">balancing machines</a> have the capability to measure the dynamic unbalance starting from 70 RPM. <br />
<br />
The unbalance effect (centrifugal force) increases with speed, the electric signal increases at the same time and so machine sensitivity tends to increase because of a better ratio signal to noise.<br />
Depending on the model and manufacturer optimum sensitivity values are obtainable starting from 400 to 600 RPM.<br />
<br />
Note: don’t get confused between the cause (unbalance) with its effect (centrifugal force or vibration).<br />
<br />
The effect increases with the speed while the cause (unbalance) in a rigid body does not change.<br />
<br />
For further information about any aspect of balancing please visit <a href="http://www.cembhofmann.co.uk/">www.cembhofmann.co.uk</a> or call our expert team today on 0161872 3123.<br />
<br />Anonymoushttp://www.blogger.com/profile/02324188011445948438noreply@blogger.com0tag:blogger.com,1999:blog-6510869221882191975.post-48728116099750058312013-04-26T04:56:00.001-07:002013-05-14T06:20:43.786-07:00Dynamic Balancing<br />
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;">
<o:p> </o:p></div>
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;">
<o:p>Dynamic balancing a rotor means to reduce its dynamic unbalance to zero or to an acceptable level. </o:p><br />
<o:p></o:p><br />
<o:p>This process will eliminate costly and sometimes irrepairable damage to the unit and is absolutely essential to the maintenance and quality of rotating parts.</o:p></div>
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;">
<o:p></o:p> </div>
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;">
<o:p>The dynamic unbalance is by definition:</o:p></div>
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<o:p></o:p> </div>
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<a href="http://1.bp.blogspot.com/-tRTKnXVv48o/UXppL7KOWaI/AAAAAAAAADM/tQ9MfG_i-0E/s1600/Titan+26-Apr+12.469.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img alt="Dynamic balancing" border="0" src="http://1.bp.blogspot.com/-tRTKnXVv48o/UXppL7KOWaI/AAAAAAAAADM/tQ9MfG_i-0E/s1600/Titan+26-Apr+12.469.jpg" title="Dynamic Balancing from Cemb Hofmann UK" /></a></div>
<a href="http://1.bp.blogspot.com/-tRTKnXVv48o/UXppL7KOWaI/AAAAAAAAADM/tQ9MfG_i-0E/s1600/Titan+26-Apr+12.469.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"></a><br />
<a href="http://1.bp.blogspot.com/-tRTKnXVv48o/UXppL7KOWaI/AAAAAAAAADM/tQ9MfG_i-0E/s1600/Titan+26-Apr+12.469.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"></a><br />
<div style="text-align: left;">
</div>
<o:p>So it is necessary to operate on two different planes.</o:p><br />
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;">
<o:p></o:p> </div>
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;">
<o:p>Since the dynamic unbalance equivalent ot the total unbalance Ut can be calculated with reference to two arbitrary planes, the consequence is that thte two balancing planes (where material can be added or removed) can be chosen.</o:p></div>
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;">
<o:p></o:p> </div>
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;">
<o:p>The above is valid for rigid rotors where mass distribution (local unbalances) does not vary with the speed.<br /> </o:p></div>
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;">
<o:p></o:p> </div>
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;">
<o:p>In order to balance with the minimum effort two rules are valid:</o:p></div>
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;">
<o:p> </o:p></div>
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;">
<o:p></o:p> </div>
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;">
<o:p>1) Choose balancing planes as far apart as possible </o:p></div>
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;">
<o:p></o:p> </div>
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;">
<o:p>2) Choose a balancing radius as large as possible</o:p></div>
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;">
<o:p> </o:p></div>
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;">
<o:p></o:p> </div>
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;">
<o:p>Note: by the <a href="http://www.cembhofmann.co.uk/html/dynamic-balancing-machines.html" target="_blank">dynamic balancing</a> on two different planes the total unbalance (set of local unbalances) is not reduced to zero; only the dynamic unbalance (on two planes ) equivalent to the total unbalance Ut is reduced to zero.</o:p></div>
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;">
<o:p></o:p> </div>
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;">
<o:p> </o:p></div>
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;">
<o:p> Discover more about dynamic balancing by visiting the Cemb Hofmann<a href="http://www.cembhofmann.co.uk/html/resource-centre.html" target="_blank"> resource centre</a> or call our expert balancing team on 0161 872 3123.</o:p></div>
<br />
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;">
<o:p> </o:p></div>
<b style="mso-bidi-font-weight: normal;"><span style="font-family: "Times New Roman","serif"; font-size: 12pt; mso-ansi-language: EN-GB; mso-bidi-font-size: 10.0pt; mso-bidi-language: AR-SA; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><br clear="all" style="page-break-before: always;" />
</span></b>Anonymoushttp://www.blogger.com/profile/02324188011445948438noreply@blogger.com0tag:blogger.com,1999:blog-6510869221882191975.post-76758939078974103492013-04-04T10:42:00.000-07:002013-05-14T06:21:15.114-07:00Couple Unbalance<h4>
A Definition of Couple Unbalance</h4>
<br />
The total unbalance is called couple unbalance if the equivalent unbalance is made by two vectors placed on two different planes having equal values and opposite directions.<br />
<br />
(The axis of inertia cuts the axis of rotation passing through the centre of mass)<br />
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="http://3.bp.blogspot.com/-NZly5Rbg5js/UV26qT4mdMI/AAAAAAAAAC8/p4YKiFywtNw/s1600/Titan+04-Apr+18.38.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img alt="Balancing Machines and Services" border="0" height="231" src="http://3.bp.blogspot.com/-NZly5Rbg5js/UV26qT4mdMI/AAAAAAAAAC8/p4YKiFywtNw/s1600/Titan+04-Apr+18.38.jpg" title="Balancing Machines and Services from Cemb Hofmann UK" width="400" /></a></div>
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Of course values Us and Ud (unbalance value in the two sections) are equal.</div>
<div class="separator" style="clear: both; text-align: left;">
</div>
<div class="separator" style="clear: both; text-align: left;">
For example: if the declared couple unbalance value is 6000 gr.cm.cm and the distance between the two balancing planes is 15 cm, then the unbalance per plane is 6000/15 =400gr.cm (4000 g.mm ). If the balancing radius on each plane is 20 cm, then the unbalance per plane is 400/20=20grams (the two unbalances on each plane are equal in value but opposite in the angle position) </div>
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<div class="separator" style="clear: both; text-align: left;">
For more information on balancing or sub contract <a href="http://www.cembhofmann.co.uk/html/dynamic-balancing-machines.html" target="_blank">dynamic balancing services</a>, please call our expert today on 0161 872 3123 or visit the<a href="http://www.cembhofmann.co.uk/" target="_blank"> Cemb Hofmann UK</a> site.</div>
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Anonymoushttp://www.blogger.com/profile/02324188011445948438noreply@blogger.com0tag:blogger.com,1999:blog-6510869221882191975.post-48972606599317427172013-04-04T10:30:00.001-07:002013-05-14T06:21:40.229-07:00Static Balancing<h4>
A definition of static unbalance</h4>
<br />
The total unbalance is called static if it is equivalent to a single unbalance vector placed in a section which also contains the centre of mass of the rotor.<br />
<br />
(The axis of inertia is parallel to the axis of rotation)<br />
<br />
<br />
<br />
<div class="separator" style="clear: both; text-align: center;">
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<br />
<br />
<br />
If the equivalent vector is not located in one section containing also the centre of mass we call it quasi-static unbalance.<br />
<br />
In practice most people call static unbalance the total equivalent unbalance when it is placed in a single plane only.<br />
<br />
Cemb Hofmann specialise in <a href="http://www.cembhofmann.co.uk/html/static-balancing-machines.html" target="_blank">static balancing machines</a> and our expert team will be delighted to guide you through our balancing processes - from professional balancing machines to sub contract balancing services. <br />
<br />
Call us now on 0161 872 3123 or visit the <a href="http://www.cembhofmann.co.uk/" target="_blank">Cemb Hofmann UK</a> site today.<br />
<br />Anonymoushttp://www.blogger.com/profile/02324188011445948438noreply@blogger.com0tag:blogger.com,1999:blog-6510869221882191975.post-60453041457190428212013-03-21T12:21:00.001-07:002013-05-14T06:22:03.150-07:00A Definition of Unbalance<h3>
None uniform mass distribution around the axis of rotation</h3>
<br />
A Rotor is unbalanced when its mass is not evenly distributed around the axis of rotation<br />
From definition it is clear that it makes no sense to speak of unbalance without defining the axis of rotation, that is the ideal line around which the mass distribution is considered.<br />
<br />
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<span style="font-family: "Times New Roman","serif"; font-size: 10pt; mso-ansi-language: EN-GB; mso-bidi-language: AR-SA; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"></span><br />
Every rotor can be divided into different sections (perpendicular to the axis of rotation) each one having its own unbalance.<br />
<br />
When in rotation, a rotor experiencing unbalance will want to revolve around its mass centre axis and because this motion is restricted by bearings, the resulting centrifugal fource will cause excessive vibration.<br />
<br />
This vibration can be catastrophic - creating unnecesary wear to bearings and more noise.<br />
<br />
If the correct action is not taken to address unbalance, the result can be as dramatic as a total breakdown of the rotor.<br />
<br />
Therefore, if you would like to speak to a balancing expert - get in touch with Cemb Hofmann UK on 0161 872 3123 today.<br />
<br />
We have extensive expertise in this field, from <a href="http://www.cembhofmann.co.uk/html/dynamic-balancing-services.html" target="_blank">dynamic balancing services</a> to machine sales and even training course - we will be delighted to talk you through the right approach to correcting whatever unbalance your machinery parts may be experiencing.<br />
<br />Anonymoushttp://www.blogger.com/profile/02324188011445948438noreply@blogger.com0tag:blogger.com,1999:blog-6510869221882191975.post-7286270348195516522013-03-07T11:00:00.002-08:002013-03-21T12:40:36.564-07:00Balancing Rotors<br />
<h2 style="margin: 3pt 0cm 12pt; mso-list: none;">
<span style="mso-ansi-language: EN-GB;">Balancing Rotors: The Basic Principles</span></h2>
<h3>
<span style="mso-ansi-language: EN-GB;">Balancing
requirements</span></h3>
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;">
Unbalance control and measurement of rotating bodies is
becoming more important for different reasons:<o:p> </o:p></div>
<br />
<div class="num" style="margin: 0cm 0cm 0pt;">
1) Higher operating speeds (more production)<o:p> </o:p></div>
<br />
<div class="num" style="margin: 0cm 0cm 0pt;">
2) Lighter construction (lower production costs)<o:p> </o:p></div>
<br />
<div class="num" style="margin: 0cm 0cm 0pt;">
3) Service speeds near to critical speeds (technical or space
reduction does not allow more rigid construction)<o:p> </o:p></div>
<br />
<div class="num" style="margin: 0cm 0cm 0pt;">
4) Longer component life (bearings for instance)<o:p> </o:p></div>
<br />
<div class="num" style="margin: 0cm 0cm 0pt;">
5) Lower maintenance costs (for repair and component exchange) <o:p> </o:p></div>
<br />
<div class="num" style="margin: 0cm 0cm 0pt;">
6) Longer machine availability (fewer production stoppages)</div>
<div class="num" style="margin: 0cm 0cm 0pt;">
<o:p> </o:p></div>
<br />
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;">
It is important to point out that the measurement of unbalance
is a quality control process at the end of manufacture or production line. It
reveals errors on dimension tolerances, casting faults, uneven parts and is an
index for the quality of the final product. </div>
<h3>
<span style="font-family: "Times New Roman","serif"; font-size: 12pt; mso-ansi-language: EN-GB; mso-bidi-font-size: 10.0pt; mso-bidi-language: AR-SA; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><br clear="all" style="page-break-before: always;" />
</span><span style="mso-ansi-language: EN-GB;"><span style="mso-list: Ignore;">A Definition Of Unbalance</span></span></h3>
<br />
<h3 class="MsoNormal" style="margin: 0cm 0cm 0pt;">
<em>None uniform mass
distribution around the axis of rotation</em><o:p> </o:p></h3>
<br />
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;">
A Rotor is unbalanced when its mass is not evenly distributed
around the axis of rotation<o:p></o:p></div>
<br />
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;">
From definition it is clear that it makes no sense to speak
of unbalance without defining the axis of rotation, that is the ideal line
around which the mass distribution is considered.<br />
<br />
</div>
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<a href="http://4.bp.blogspot.com/-L-HKkkIYVro/UT4sKu1QS1I/AAAAAAAAACE/8JegeVELJ04/s1600/Titan+11-Mar+19.10.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img alt="A definition of unbalance" border="0" height="158" src="http://4.bp.blogspot.com/-L-HKkkIYVro/UT4sKu1QS1I/AAAAAAAAACE/8JegeVELJ04/s400/Titan+11-Mar+19.10.jpg" title="Balancing: A definition of unbalance" width="400" /></a></div>
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Every rotor can be divided into different sections (perpendicular to
the axis of rotation) each one having its own unbalance. </div>
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<o:p>I will be blogging with more information about couple, static and dynamic unbalance over the next few weeks so please feel free to ask any questions in the meantime - if you are experiencing a particular aspect of ubalance then Cemb Hofmann UK can most certainly be of service.</o:p></div>
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<o:p>If you want to find out more about any aspect of balancing just <a href="http://www.cembhofmann.co.uk/">visit our site</a>!</o:p></div>
Anonymoushttp://www.blogger.com/profile/02324188011445948438noreply@blogger.com0Cemb Hofmann UK, 1 Longwood Road, Trafford Park, Stretford M17 1PZ, UK53.4669517 -2.323568900000054853.4645887 -2.3286114000000548 53.469314700000005 -2.3185264000000547