Rotating Machinery, such as fans, blowers, centrifuges, motors, generators, flywheels, pump impellers etc generate undesirable vibrations due to the residual centrifugal forces of an imbalanced rotor. These forces act cyclically on bearings and structural elements of the machine, and eventually lead to premature metal fatigue and failure. Also, the vibration consumes considerable energy, acts as a source of noise, and leads to operator fatigue. It is therefore important to control the balance conditions of all rotating equipment.
A level of unbalance that is acceptable at a low speed is completely unacceptable at a higher speed. This is because the unbalance condition produces centrifugal force, which increases as the speed increases. The force caused by unbalance increases by the square of the speed. If the speed is doubled, the force quadruples; if the speed is tripled the force increases by a factor of nine. Modern man still suffers from the same problem – only now the problem is amplified. As machines get bigger and go faster, the effect of the unbalance is much more severe. It is the force that causes vibration of the bearings and surrounding structures. Prolonged exposure to the vibration results in damage (Fatigue Failure and Creep Failure) and increases downtime of the machine. Vibration can also be transmitted to adjacent machinery, affecting their accuracy or performance.
There are many causes contributing to an unbalance condition, including (1) material problems such as density, porosity, voids, flaws and blowholes (2) fabrication problems such as misshapen castings, eccentric machining and poor assembly (3) distortion problems such as rotational stresses, aerodynamics and temperature changes. Many of these occur during manufacture, others during the operational life of the machine. When a rotor has been in service for some time, various other factors can contribute to the balance condition. These include corrosion, wear, distortion, and deposit build up. Deposits can also break off unevenly, which can lead to severe unbalance. This particularly applies to fans, blowers, compressors and other rotating devices handling process variables. Routine inspection and cleaning can minimize the effect, but eventually the machines will have to be removed from service for balancing.
Identifying and correcting the mass distribution and thus minimizing the force and resultant vibration is the technique known as dynamic balancing. More and more users are realizing the tremendous economic benefits of having an active vibration control program for rotating machinery. As an example, the Indian Railways is understood to have reduced the out-of-service ratio of locomotives from 18% to less than 1% by mandating balancing of the blowers on the loco. Several companies have confirmed huge reduction in costs of bearing replacements and up to 20% savings in power consumption.
Many rotors can often be balanced in place (Called “Field Balancing”), running at their own operating speed, with minimum disassembly. To balance in place, of course, a basic requirement is that the rotor has to be accessible to make corrections. Machines such as fans and blowers are good examples. We prefer to do “Field Balancing” with the help of our state of the art – Vibration Analyzer cum Balancer Equipment.
Modern instruments such as vibration analyzers, data collectors and portable balancers provide accurate information to assist in the balancing process. The vibration level measured at the rotating speed frequency is used as an indicator of the amount of unbalance. The location is determined by measuring the phase. Phase (the relative motion of one part of a machine to another) is measured by means of a stroboscopic light or by an indicator in the instrument, triggered by a photocell.
Ascentech Engicon Pvt. Ltd. is having Vibration Analyzer cum Balancer BASELINE 6050, which is a two-channel, with 2 inputs for accelerometer sensors for sensing vibration, and one optical phase reference sensor. Its powerful DSP microcontroller has an efficient a logarithm for the extraction of cyclicality and vector measurement even amidst presence of a large noise in the rotor. Two- plane and single-plane dynamic balancing can be performed in-situ with this instrument. It has all the required vector calculation algorithms built into its program. Thus the operator is freed from the task of determining the weights by calculations or hit-and-try methods, resulting in vastly improved, quick and accurate results.
Our Company is having a team of STATIC AND DYNAMIC BALANCING EXPERTS with a vide range of most sophisticated and modern imported On-Site Field Balancing Equipments with a highly dedicated and experienced expert team of Mechanical and Electrical Engineers.