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Under conditions where rotating speed is very high even though the mass is low, as in gas turbines or jet engines, or under conditions where rotating speed is low but the mass is high, as in ship propellers, balance of the rotating system should be highly considered, because it may generate large vibrations and cause failure of the whole system.
The balance shaft runs off the small gear on the left (the large gear is for the camshaft, causing it to rotate at half the speed of the crankshaft). Balance shafts are often used in inline-four engines, to reduce the second-order vibration (a vertical force oscillating at twice the engine RPM) that is inherent in the design of a typical inline ...
As the speed of rotation increases the amplitude of vibration often passes through a maximum that is called a critical speed. This amplitude is commonly excited by imbalance of the rotating structure; everyday examples include engine balance and tire balance.
Excessive hammer blow from high slipping speeds was a cause of kinked rails with new North American 4–6–4s and 4–8–4s that followed the 1934 A.A.R. recommendation to balance 40% of the reciprocating weight. [8] Out-of-balance inertia forces in the wheel can cause different vertical oscillations depending on the track stiffness.
A 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.
A static balance (sometimes called a force balance [2] [3]) occurs when the inertial axis of a rotating mass is displaced from and parallel to the axis of rotation.Static unbalances can occur more frequently in disk-shaped rotors because the thin geometric profile of the disk allows for an uneven distribution of mass with an inertial axis that is nearly parallel to the axis of rotation.
The rotation speed problem comes into effect when the differential gearing is a high ratio and an overdrive is used to compensate. This may create unpleasant vibrations at high speeds and possible destruction of the driveshaft due to the centripetal forces or uneven balance.
A cycloidal drive or cycloidal speed reducer is a mechanism for reducing the speed of an input shaft by a certain ratio. Cycloidal speed reducers are capable of relatively high ratios in compact sizes with very low backlash. [1] The input shaft drives an eccentric bearing that in turn drives the cycloidal disc in an eccentric, cycloidal motion ...