This opposite trend is because that the change of leakage flux
density is opposite to the density of the magnetic flux inside the material (Galfenol beam).
It is difficult to evaluate the effect of the leakage flux
mathematically because it depends on various factors: the position of the windings relative to each other; the position of the windings in the transformer; the distance between the winding.
The flux along the rotor axis therefore significantly varies (skew leakage flux
results in energy being alternately stored in and discharged from the magnetic fields with each cycle of the power supply.
This is increasing with load and multitude of sources, such as surface and slot conditions, leakage flux
, and another name is additional load losses, it should be 10%-20% of motor rating Stray load losses: [P.sub.stay] = 50 W(16).
Its advantage is to increase leakage flux
but also increase the q-axis inductance, the armature reaction and the polar angle, so that it reduces the electromagnetic torque.
2) covering an angle of 70[degrees], which represents about 78% of polar pitch (more than 80% leads to an increase of the leakage flux
and the magnets loose in efficiency ).
The PMs are located in the leakage flux
paths, not in the main flux paths.
The interior permanent magnet motors have higher output power but more magnetic leakage flux
. Keep the total volume of permanent magnet as a constant and divide the single traditional surface-mounted TPMLWG or the interior TPMLWG into the surface-mounted part and interior part, where the former attracts magnetic flux and decreases the leakage and the later produces the main magnetic flux.
In the aligned position, the flux consists of the main flux under two poles and the leakage flux
beside the poles as follow:
3(a), there is little magnetic leakage flux
out of the soft iron, and the magnetic flux density is gathered in the air gap on the ends of the device, which improves the adhesion force.