Abstract
Earnshaw's theorem (1839) stated that no stationary object made of magnets in a fixed configuration can be held in stable equilibrium by any combination of static magnetic or gravitational forces. What will happen by a moving body like a rotating passive magnetic levitator? Nobody has given an answer until now. The author applied a self-made passive magnetic bearing to radial pump and turbine machine and found that if the rotating speed could be higher than a critical value, 3250 rpm for a pump and 1800 rpm for a turbine, the rotors would be disaffiliated from stators and keep the rotation stable. It seems that the fast rotating levitator has a so-called “Gyroeffect” which makes the passive maglev rotator stable. These results have extended Earnshaw's theorem from static to dynamic equilibrium. In static state or by a speed lower than critical value, the passive maglev rotator cannot keep rotation stable; if the rotating speed is higher than critical speed, the passive magnetic levitator will have Gyroeffect and thereby stabilize its rotation.
Highlights
In 1893, an English scientist named Earnshaw proved theoretically that a magnetic body cannot be supported in a stable manner in the field produced by any combination of mere passive magnetic poles [1]
This paper presents the permanent maglev pump and permanent maglev turbine model, demonstrates the stable levitation of the rotors, and discusses the mechanism why passive maglev can be stable in dynamic equilibrium
The author’s bearing is shown in Figure 1 (Bearing B), which has two passive magnetic rings with different outer and inner diameters but same thickness; the smaller ring is located beside the bigger ring concentrically and both are magnetized same in axial direction
Summary
In 1893, an English scientist named Earnshaw proved theoretically that a magnetic body cannot be supported in a stable manner in the field produced by any combination of mere passive magnetic poles [1]. This means that, it is impossible for a pure permanent maglev to achieve a stable equilibrium because the force of attraction (or repulsion) between two magnetized bodies is inversely proportional to the square of their separation (distance). The author applied a patented novel passive magnetic bearing [2] in rotary pump and turbine machine and found that the rotors of these devices could be levitated in a stable manner if the rotating speed were high enough. This paper presents the permanent maglev pump and permanent maglev turbine model, demonstrates the stable levitation of the rotors, and discusses the mechanism why passive maglev can be stable in dynamic equilibrium
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