In-Place Balancing & Vibration Analysis
EMX Industrial Repair’s state of the art Field Balancing Systems are designed to perform measurements of vibrations and calculations within the existing assembly. This allows machinery to be left in place, on-site, at your facility, which reduces overall downtime and associated labor costs, and at times may improve balancing accuracy, as the rotating component is spun on it’s originally designed axis and bearing housings. Some examples of machinery balanced in-place, are typically Fans, Blowers and Turbines, because of the designed rotor access enables the ability to add or remove weights to rotating element. The balancing application measures the running speed (1X) filtered vibration amplitude and relative phase with a reference mark in the rotor to allow full balancing correction. All Balancing results will be performed to the level specified by the customer. In the absence of a requested level, dynamic balancing to balance quality grade G2.5 (ISO 1940/1) should enable the machine to meet final vibration limits. A Balance weight or weights are secured to rotor and will be located so that they do not interfere with other machine components. Good documentation is important in balancing. It is a record of who performed the balancing, when it was done and how well it was done. All work is electronically documented and a machine balancing report, with balancing data, as well as original and final results is generated upon completion of job.
Why Balance ?
Rotating components experience significant quality and performance improvements when balanced. Balancing is the process of aligning a principal inertia axis with the geometric axis of rotation through the addition or removal of material. By doing so, the centrifugal forces are reduced, minimizing vibration, noise and associated wear. Virtually all rotating components experience significant improvements when balanced. Balancing can contribute to more efficient, more powerful,quieter, smoother running and longer lasting equipment and is one of the most cost effective means of providing value to our customer.
Think of imbalance as an imaginary heavy spot on a rotating shaft. This heavy spot is pulling the shaft and the center of rotation of the center line off the shaft on every rotation. The force of the imbalance is transferred to the bearing and case of the machine causing heat, friction, lubrication failure, and bearing faults. Extreme imbalance can cause looseness in the machine train. There are many reasons for imbalance to be present in a rotor. Deposit and build-up causes imbalance as deposits of dirt and grime build up on a rotor and its parts over time. The build-up of these deposits may be gradual, but not necessarily equal and can cause an imbalance condition. While the build-up may be gradual, the deposits will break away at an uneven rate causing a more serious imbalance. This can be especially true of fan blades. Fan blades will tend to collect deposits in a linear fashion, but the deposits will not come off at the same rate. They will come off in unequal pieces causing serious imbalance. Make cleaning of rotor, rotating parts and fan blades a regular part of your scheduled inspection and preventative maintenance. Rotors can also be damaged when exposed to abrasive or corrosive materials. This will cause uneven wear and an imbalance condition. When you choose products, make sure their rotors are made from materials that can withstand corrosion and abrasion over long periods of time. Eccentricity exists when the true or geometric center-line of a part does not coincide with its rotating center. This can be a manufacturing defect. Eccentricity can also be caused by out of roundness of the shaft, variations in electrical properties or uneven heating.
At some time during a motor’s life, it is likely to experience high vibration levels. What’s behind this maintenance phenomenon? The cause may be an electromagnetic or mechanical imbalance, loose components, rubbing parts, bearing failure, or resonance.
When a problem occurs, it is critical to quickly identify the source and take corrective action. Using EMX’ latest vibration analysis diagnostic techniques can save you money and downtime. EMX’ uses VibePro 7.3.5 which is a portable device, route-based instrument used for collecting vibration data on rotating machinery. It reduces collection,analysis and reporting time, compared with similar devices. This allows EMX to determine the severity of the stress level of bearing or gear wear on your motor. The data is recorded from each machine and uploaded on the software, providing quick recognition of change in the vibration pattern, as an indicator of deterioration. Corrective actions are then taken.
Vibration in rotating machinery is commonly the result of mechanical faults including mass unbalance, coupling misalignment, loose
components, and many other causes. Improving the levels of vibration should always include elimination of the source of vibration and not addressing the symptom by making balance corrections. Mass unbalance will produce vibration due to the force generated by the eccentric weight. This force will be imposed at the running speed of the shaft, and depends on the amount eccentric mass the eccentricity of the weight , and the frequency of rotation. In more common terms the unbalance is defined by the eccentric weight, mounting radius, and shaft speed. The observed vibration signature will show elevated amplitudes at 1xRPM and no other significant frequencies when rotor unbalanced is the main fault.
Unfortunately, other common faults can also generate high levels of vibration at 1xRPM including coupling misalignment, looseness, rotor bows, and a variety of other sources. In some cases, these faults will produce other symptoms that can suggest corrections other than balancing should be done. Yet in many cases, balancing may be the chosen course of action for lowering vibration amplitudes even though it is not the source of vibration. Once it is determined that balance corrections should be made, the balancing process includes
measuring reference vibration, adding trial weights, observing the response due to trial weights, and using the response characteristics to determine the location of balance correction weights to reduce vibration to an acceptable level.
Vibration analysis and trending is a method of evaluating current machine condition and monitoring a machine’s changes over a period of time. It can also be used to pinpoint a source of several problems such as misalignment, imbalance and bearing issues. Vibration Trending and Analysis can be performed on all rotating equipment.
Benefits of Vibration Trending & Analysis
- Diagnose imbalance & misalignment
- Discover bearing issues
- Applicable on any rotating equipment
- Improve equipment reliability and uptime
- Prevent catastrophic failure
- Improve machine safety levels
Applications for Vibration Trending & Analysis
- Air handlers
Got a Balancing or Vibration Question! Contact us at 856-362-4553 or email to email@example.com