Importance of Static Portable And Dynamic Balancing
When man invented the wheel, he very quickly learned that if it wasn't completely round and if it didn't rotate evenly about its central axis, then he had a problem!
The wheel would vibrate, causing damage to itself and its support mechanism and in severe cases, be unusable. As the task of manufacturing a replacement was so huge and time consuming, a method had to be found to minimize the problem.
Research showed that the wheel and its shaft had to be in a state of balance, i.e. the mass had to be evenly distributed about the rotating centerline so that the resultant vibration was at a minimum.
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.
The main motive behind Balancing
Balancing is a process of attempting to improve the mass distribution of a body so that it rotates in its bearings without unbalanced centrifugal forces.
A dynamic balancing machine is a measuring tool used for balancing rotating machine parts such as rotors for electric motors, fans, turbines, disc brakes, disc drives, propellers and pumps. The machine usually consists of two rigid pedestals, with suspension and bearings on top supporting a mounting platform. The unit under test is bolted to the platform and is rotated either with a belt-, air-, or end-drive.
As the part is rotated, the vibration in the suspension is detected with sensors and that information is used to determine the amount of unbalance in the part. Along with phase information, the machine can determine how much and where to add weights to balance the part.
Static balancing machines differ from hard- and soft-bearing machines in that the part is not rotated to take a measurement. Rather than resting on its bearings, the part rests vertically on its geometric center. Once at rest, any movement by the part away from its geometric center is detected by two perpendicular sensors beneath the table and returned as unbalance. Static balancers are often used to balance parts with a diameter much larger than their length, such as fans. The advantages of using a static balancer are speed and price. However a static balancer can only correct in one plane, so its accuracy is limited.
Portable balancing machines are used to balance parts that cannot be taken apart and put on a balancing machine, usually parts that are currently in operation such as turbines, pumps, and motors.
Portable balancers come with displacement sensors, such as accelerometers, and a photocell, which are then mounted to the pedestals or enclosure of the running part. Based on the vibrations detected, they calculate the part's unbalance. Many times these devices contain a spectrum analyzer so the part condition can be monitored without the use of a photocell and non-rotational vibration can be analyzed.
Dynamic Balancing Services of machines are provided by different engineering industries. It is essential to select the best among them who fulfills all the credentials.