Hyperloop
1.2 Linear Synchronous Motor (LSM)
There are lots of variations of synchronous motors, but only one of them can be ‘unrolled’ into a LSM and used in a Maglev. It is the Permanent Magnet Synchronous Motor (PMSM). LSM is similar to LIM. The main difference is that, in LSM, rotor speed is equal to synchronous speed, which is where its name comes from. This motor is also self-starting and, furthermore, more energy-efficient, since there are fewer losses through heat from conductors. However, LSMs have a more complicated construction, since they make use of permanent magnets and require a feedback loop for determining the position of the vehicle on the track. This motor also creates a travelling MF in the stator (track) using a 3-phase AC, and the vehicle is equipped with strong SC magnets with varying polarity or in Halbach arrays. The MF travels with a phase difference of 90 o so that there is no net transverse force. The acceleration is controlled by varying the current flowing through the coils.
An intelligible visualization of this principle can be seen in figure 7 (below). The train shown is the JR Central SCMaglev, which set the world speed record for trains in 2015, reaching 603 km/h.
Permanent magnets
Figure 7
2.
Magnetic levitation
Magnetic levitation excludes energy losses due to friction by eliminating all moving parts. Today there exist three major types of magnetic suspension: EMS (ElectroMagnetic Suspension), EDS (ElectroDynamic Suspension) and Inductrack.
107
Made with FlippingBook Digital Publishing Software