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A Comprehensive Review on Energy Storage Systems
Published in Krishan Arora, Suman Lata Tripathi, Sanjeevikumar Padmanaban, Smart Electrical Grid System, 2023
A. Gayathri, V. Rukkumani, V. Manimegalai, P. Pandiyan
Figure 15.6 depicts a FES system that stores energy with very low frictional losses by utilizing kinetic energy stored in a spinning mass. Through the use of coupling of motor–generator, electric energy is used to accelerate the mass to speed. The energy is discharged by removing the kinetic energy from a specific point in time using the same motor–generator. The amount of energy stored is proportional to the moment of inertia times the angular velocity squared of the object. To maximize the energy-to-mass ratio, the flywheel must spin at the quickest possible speed. Rapidly rotating objects are subjected to significant centrifugal forces. Dense materials can store more energy than low-density materials, but they are also exposed to increased centrifugal force, and as a result, they may be more prone to failure at lower rotational speeds.
Dynamics in Roadways
Published in M Rashad Islam, A K M Monayem H Mazumder, Mahbub Ahmed, Engineering Dynamics, 2022
M Rashad Islam, A K M Monayem H Mazumder, Mahbub Ahmed
Note that while centripetal force is an actual force, centrifugal force is defined as an apparent force. In other words, when twirling a mass on a string, the string exerts an inward centripetal force on the mass, while mass appears to exert an outward force on the string. If you are observing a rotating system from the outside, you see an inward centripetal force acting to constrain the rotating body to a circular path. However, if you are part of the rotating system, you experience an apparent centrifugal force pushing you away from the center of the circle, even though what you actually feel is the inward centripetal force that is keeping you from, literally, going off on a tangent. To balance the effect of outward centrifugal force, the road is inclined at an angle of θ (Figure 6.10) toward the center of the curvature. The slope of this inclination is called the superelevation (e). The minimum radius of curvature (R) for a circular motion can be determined using the following relationship: Frictional force=f×normal reaction=fWcosθ+mv2Rsinθ
Rotor Design
Published in Wei Tong, Mechanical Design and Manufacturing of Electric Motors, 2022
During rotor rotation, centrifugal forces are produced in the rotor and in turn generate stresses in the circumferential and radial directions. In general, hoop tensile stresses are dominant and play a decisive role in the selection of rotor material. The stress resulted from centrifugal loading is governed by the radial equilibrium equation in the cylindrical coordination system [2.88]: dσrdr+1r(σr−σθ)+ρω2r=0
Feedforward Compensation Control of A Bearingless Induction Motor Based on RBF Neural Network
Published in International Journal of Electronics, 2021
Haitao Mei, Zebin Yang, Qifeng Ding, Peijie Jia
It is unavoidable for BL-IM to balance the rotor mass eccentricity during machining. It generates huge centrifugal force during high-speed rotation and produces unbalanced vibration, which affects the stability of the suspension system (Sreejeth et al., 2019). The existence of the rotor mass eccentricity causes the rotor mass centre c and the geometric centre m not to be at the same point, and their distance is , Figure 3 is the rotor mass eccentric. The rotor is subjected to unbalanced magnetic pulling force and centrifugal force, which generates the radial vibration and causes the uneven distribution of the air gap magnetic field due to the mass eccentricity. The magnitude of the centrifugal force is proportional to the square of the rotational speed. When the rotational speed is much rapid, the amplitude of the radial vibration will increase sharply, and then the vibrational force will be transmitted to the base, therefore the system will be vibrated. In addition, if the amplitude of the feedback vibration signal is too large, the current in the power amplifier will saturate to jeopardise the control loop of the system seriously.
Structural Analysis of Induction Machine and Switched Reluctance Machine
Published in Electric Power Components and Systems, 2019
Lizon Maharjan, Shiliang Wang, Babak Fahimi
Centrifugal force depends on the rotational speed and the mass of the rotating body. For verification purposes, rotational speed of 314 rad/s was applied to the outer disk presented in Figure 2, and the maximum normal stress obtained through FEA was compared with theoretical calculation. The comparison is included in Table 1, the percent error between calculated and simulated value is 3.88%. The theoretical calculation was made based on Eq. (11) [17]. where, = radial stress at r, = max radial stress, = density, = outer radius of the disk, = inner radius of the disk, = radius of stress calculation, ω = rotational speed.
Advanced Gravity Concentration of Fine Particles: A Review
Published in Mineral Processing and Extractive Metallurgy Review, 2018
EGS have been used for fine mineral and coal concentrations for years. The separation principle of EGS is similar to that of any other conventional gravity separator, i.e., principle of differential settling velocities. However, unlike conventional gravity separators, a centrifugal force is applied to enhance the differential settling velocities between heavy and light particles. When particles are subjected to centrifugal force they are made to settle in the fluid in the radial direction. Depending on the centrifugal force and mass of the particle (which is related to particle size and density), each particle moves with a different settling velocity which helps separate particles from each other. The outward centrifugal force acting on the particle is quantified as: , where m is the mass of the particle, ω is the angular velocity, and r is the radial location of the particle. In this case, ω2r is the centrifugal acceleration and is often 50 times or more of the gravitational acceleration. This enhanced radial acceleration is referred to as the enhanced gravity effect. The buoyancy force, Fb, is inward and is dependent on the particle volume and the density of the fluid. The third force acting on the particle is the fluid drag, Fd, and for small particles it will be essentially the viscous resistance (Majumder and Barnwal 2006). The motion of the particle is governed by the influence of these three forces neglecting the interactive forces. Thus, the simplified force balance on the particle can be written as: