Search results
Results From The WOW.Com Content Network
When an element of mass is offset from the axis of rotation, centrifugal force will tend to pull the mass outward. The elastic properties of the shaft will act to restore the “straightness”. If the frequency of rotation is equal to one of the resonant frequencies of the shaft, whirling will occur. In order to save the machine from failure ...
Stiffness of the shaft and its support; Total mass of shaft and attached parts; Unbalance of the mass with respect to the axis of rotation; The amount of damping in the system; In general, it is necessary to calculate the critical speed of a rotating shaft, such as a fan shaft, in order to avoid issues with noise and vibration.
Analysis shows that there are well-damped critical speed at lower speed range. Another critical speed at mode 4 is observed at 7810 rpm (130 Hz) in dangerous vicinity of nominal shaft speed, but it has 30% damping - enough to safely ignore it. Analytically computed values of eigenfrequencies as a function of the shaft's rotation speed. This ...
Cutting speed may be defined as the rate at the workpiece surface, irrespective of the machining operation used. A cutting speed for mild steel of 100 ft/min is the same whether it is the speed of the cutter passing over the workpiece, such as in a turning operation, or the speed of the cutter moving past a workpiece, such as in a milling operation.
The critical speed varied from 95 RPM for a Baldwin tandem compound to over 310 RPM for a Cole compound Atlantic. the horizontal motion at the pilot. As an example, the Baldwin compound Atlantic moved about 0.80 inch at 65 MPH compared with 0.10 inch for the Cole compound Atlantic.
The compressor flow and pressure range is shown with a carpet plot of engine constant rpm and constant torque lines superimposed on the map. OpenCourseWare material [ 45 ] shows a carpet plot of engine speed and load for the airflow requirements of 4-stroke truck engine.
The ISO 1940 standard defines balance grades for different classes of machinery. A rotor balanced to G2.5 will vibrate at 2.5 mm/s at operating speed if rotating in a suspended state with no external influences. U per = (9.54 × G number × mass)/rpm. Where U per = balance tolerance (or) residual imbalance
Rotational frequency, also known as rotational speed or rate of rotation (symbols ν, lowercase Greek nu, and also n), is the frequency of rotation of an object around an axis. Its SI unit is the reciprocal seconds (s −1 ); other common units of measurement include the hertz (Hz), cycles per second (cps), and revolutions per minute (rpm).