Hyperloop
Figure 3
Figure 4
Figure 2
Figure 2 is an illustration of Biot-Savart ’s Law. When a 3-phase AC (fig. 3) is applied to a stator winding shown in Figure 1, a rotating, or in the case of LIM, a travelling, magnetic field (MF) is created according to Biot-Savart ’s Law. Synchronous speed is the angular velocity of the MF, or speed of MF for LIMs. When a stationary closed conducting loop is placed inside this winding (fig. 4), magnetic flux through it constantly changes. In obedience to Faraday’s Law, EMF is induced in the loop proportional to the rate of change of flux: where Φ B is the magnetic flux and N is the number of turns of wire in loop
Φ B = B * A * cosθ, where A is the area of the surface, and θ is the angle between the magnetic field lines and the normal to A
Speed synch (in RPM) = 120 x Frequency of AC (Hz) / # poles
Lenz’s Law states that ‘the direction of an induced current is always such as to o ppose the change in the circuit of the MF that produces it’. Therefore, the current interacts with the original field, torque is applied to the loop in form of Ampere Force (fig. 6) in the direction determined by LHR (fig. 5) and the conductor starts rotating. In LIMs currents are induced in ladder-arranged conductors and thrust is produced instead of torque. However, for a LIM to generate thrust, synchronous speed has to be greater than the speed of secondary, so that magnetic flux changes constantly.
F A = B * l * I * sin θ, where I is current flowing through conductor, l is length of conductor, B is magnetic induction, θ is the angle between the vectors of magnetic induction and the direction of current flow
Figure 5
Figure 6
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