19. Appendix 4
Option designing of motor rotor equipped by movable loads with permanent magnets
the shapes of which are close to the shape of bar magnets

The previous chapters examined the engine design, the rotor of which is equipped by cylindrical loads with the magnets of annular shape. However, the force interaction of the movable magnets of such form with pole planes of the stationary magnets rectangular shape is not sufficiently effective. Force interaction of magnets decreases with the square of length of the air gap between the opposing elements of polar surfaces of the interacting magnets. Therefore, has been natural the desire to use for movable loads the magnets of the rectangular shape (bar-shape). Unfortunately, the search for solutions to this problem has not been successful for a long time. And yet, the possibility of use for movable loads the magnets with the shape close to rectangular was found! However herewith, the design of the movable loads became more complicated.

In Fig. 41 is shown mutual arrangement of the movable loads equipped with permanent magnets of bar shape and the stationary permanent magnets similar shape. The stationary magnets are located near the path of movement of the movable loads. In this drawing is shown the cross section of the magnets by the plane which passes in the middle of the space between two coupled disks and is perpendicular to the axis of rotation of the disks. Polar surfaces of the interacting magnets are rounded. Radii rounding off these surfaces are slightly smaller of radius the outer circumference of the disk. The stationary magnets of the sector A₆ – O – A₇ which, due to using the phenomenon of levitation, provide the lifting up of the movable loads, during their moving above them, also have the bar-shape, but somewhat different from the shape of the other stationary magnets. Orientation of the magnetization is conditionally shown in red and blue colors. In this figure you may see also the cross-sections of adapters that connect magnets of the movable loads with fittings for moving along the inclined paths built-into the disks. The cross sections of the adapters are shown with grey color.

Fig. 41

Comparing Fig. 41 with the Fig. 11, where is shown, likewise, the cross section of the rotor magnets of the embodiment using the loads of cylindrical shape with the annular magnets, it can be seen that the area of pole surface of the each magnet of movable load, effectively interacting with the area of pole surface of the adversarial stationary magnet, in the embodiment using the movable magnets of bar-shape is substantially larger.

Fig. 42 illustrates the interaction of the vectors magnetic (F_M) and gravitational (F_g) impacts applied to the center of gravity of a movable load in one of the states of rotation.

Fig. 42

Herewith may be seen that the vector F_M provides additional rotational force in the desired direction (counterclockwise).

The orientation of stator magnets to attraction of the movable magnets passing the sectors A₁ – O – A₂ and A₉ – O – A₁₀ is also possible as in the embodiment with cylindrical loads. Advantages of such orientation are explained in Appendix 3. Option to such use of the stationary magnets is shown in Fig. 43.

Fig. 43

(The cross-sections of the adapters are not shown in this figure, in order not to reduce the visibility of magnetic interaction.)

Ingredients and structure of a movable load are explained with aid of Figures 44 and 45.

Fig. 44

Fig. 45

The wheels with bearings are shown in the figures 44 and 45 rather conventionally and oversimplify. When real designing the developer must choose from the many available types of bearings destined for moving along linear paths those which correspond to significant axial efforts generated at moving the heavy loads. And also is necessary to pay attention to the requirements for lubrication and other characteristics of bearings which must be chosen. Profiles of the inclined paths, embedded into the coupled disks, must be consistent with the shape of external surfaces of the bearings to minimize the mutual friction.

In Fig. 46 are shown three-dimensional images of the rotor of motor surrounded by the stationary magnets.

Fig. 46

When designing and experimental development of the motor should be considered the advices and recommendations contained into the Chapters 11, 12 and 17 of the main text.

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In conclusion, it should be noted that the advantage of using magnets of bar-shape for movable loads of rotor is not only in the greater efficiency of the force interaction with the stationary magnets, but also in that at the same geometrical dimensions of the coupled disks and at the same distance between them (as it can be chosen for the motor with the loads of cylindrical form) the loads with magnets of bar-shape are possible better utilize the volume of the space between the disks, i.e. the loads can have greater mass and, accordingly, greater weights. Hence, the impact of gravitation to the loads, providing the initial torque on the shaft of the motor, must be greater.

It should also be noted as an advantage - the absence of necessity to perform the loads in two alternating varieties, as is case in the design of the motor rotor equipped with annular magnets, as it described in 7 (Fig. 6).

This Chapter was added 3 July 2014

This page was last modified on 9 September 2016