Transformers installed indoors transmit vibrations to the surrounding areas, resulting in an unpleasant tonal noise commonly known as ‘transformer hum’. In addition to structure-borne noise, transformers generate airborne noise (noise emitted through air), albeit to a lesser degree. Given that structure-borne noise is the primary mechanism of noise transmission in a transformer, it is essential […]
Read MoreThe support structure of a massive, 110,000 lb, industrial process equipment, subject to random perturbation, is isolated from the vibration of the equipment itself. The isolators used in the random vibration isolation system are made up of low-stiffness springs paired with viscous dampers. Motion control schemes were incorporated into the isolation system to manage […]
Read MorePrecision devices such as coordinate measuring machines (CMMs), microscopes, MRI machines, and other test/scanning equipment are highly sensitive to vibration, caused by other nearby equipment or even human activities. The adverse effects of vibration on such devices should be mitigated by properly isolating them from the surrounding via elastically mounting them on their support concrete […]
Read MoreAir mounts, with their attractive attribute of being able to provide the most softness of all mounts of comparable size, have been gaining popularity and widespread use. The drawback of soft mounting is occasional excessive motion of the mounted machine in response to abrupt, impulse-like disturbances (such as starting up or shutting down an engine). […]
Read MoreCompared to elastomeric (rubber) and coil spring mounts, air mounts with their very low stiffness, provide the highest degree of low-frequency vibration isolation. Lack of damping in air mounts, although lowers the noise and vibration transmission of the mounted machine, will deteriorate its shock isolation attributes. This is mainly due to the creation of a […]
Read MoreAn Advanced Mounting System for Diesel Generators Onboard Luxury Watercrafts An ideal mounting system for yacht diesel generators should be ‘soft and highly underdamped’, while the yacht is not moving, i.e., the propulsion engines are off and calm and quiet are expected. This will prevent the transmission of vibration and noise, through the hull, to […]
Read MoreTransformer noise (hum) is caused by the extension and contraction of the core laminations when magnetized (a phenomenon is known as magnetostriction). This extension and contraction (vibration) take place twice during a normal voltage or current cycle. That is, the transformer vibrates mainly at twice the frequency of the supply, i.e. 120 Hz in North […]
Read MoreA novel, feed-forward vibration isolation scheme is developed that addresses the shortcomings of adaptive feedforward vibration isolation algorithms. This scheme which is based on the use of Kalman estimators (KE) does not require real-time adaptation and yet maintains its effectiveness when the attributes (such as the frequencies) of the disturbance changes. More importantly, it does […]
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