The effectiveness harnessing of the impact of gravitation in this device is largely dependent on the ratio of values Rmax and Rmin. The ratio Rmax/Rmin should be as large as possible, because the initial net torque on the motor shaft, that is created due to use of kinetic energy of gravitation, is largely determined by the difference in the length of the lever arms of rotation formed by the cylindrical loads. Evidently, that increasing of the ratio of Rmax/Rmin can be actualized due to the decreasing Rmin and increasing Rmax. The possibility of increasing Rmax is restricted by allowable dimensions of the whole device and by its cost. That is, the value Rmax can be determined only after the decision with regard to the size of the outer diameter of the disk. The possibility of decreasing the size of Rmin is limited by the fact that adjacent cylindrical loads, on passing through the sectors a11 – O – a1 and a1 – O – a3 (Fig. 2 and Fig. 11), are moving too close to each other. This means that the value of Rmin can be determined only after a decision in regard to the size of the outer diameter of the cylindrical load. The larger outer diameter of the load, the greater its mass and, consequently, more the force of gravitational impact on each movable load. Here, this ratio has been chosen to be equal to two (Rmax/Rmin = 2) only to simplify the calculations. The developer of the real motor should come on his own to the compromise decision between the desire to increase the outer diameter of the load and the desire to diminish the value of Rmin.
In the above technical drawings and calculations the number of loads was decided equal to 16. This choice was made only for the convenience of drawing pictures in the early stages of this work (It was conveniently to divide the circle consistently by 2 and to receive, respectively, the numbers: 2, 4, 8, 16). At real designing it can be taken another quantity of loads that is different from 16, including an odd number. At this, to ensure greater uniformity of rotation, the inclined paths of the disk should be embedded symmetrical and uniformly with respect to its center.
Volume of the cylindrical load is proportional to its length, i.e. than the length greater, by that greater the volume and, accordingly, greater the weight of the load. However, the choice of length of the loads is limited by the distance between the pair of connected disks, i.e. by the distance which is admitted in the chosen device.
In the above technical drawings and in the corresponding calculations the angle between direction of the linear trajectory path of centre of gravity of each load and direction of the ray, emanating from the axis of rotation (from the point of “O” in Fig. 2) and passing through the point “a”, corresponding to this load, assumed to be 45° (the direction to counter clockwise is accepted as the positive direction of indication of this angle). This value of the angle of inclination at the chosen quantity of inclined paths (16) and taken the ratio of the geometric dimensions of basic elements of the design is supposed as optimal. The increasing of this angle would have led to some increase of the gravitational component of the net torque. However, the possibility of such increasing is limited structurally by the allowable proximity of external parts of the armature of the adjacent inclined paths (near to the circumference Rmin).
As it have been pointed out previously, the net torque on the motor shaft that is produced by the moveable loads due to the gravitation impact directly proportional to the force of gravity attraction acting on each load Fg. The magnitude of force Fg corresponds to the weight of the load. That is, for a developer of the motor quite naturally the desire to increase the mass of load, that, in turn, will require the application of permanent magnets capable of creating strong fields. This requirement necessitates the use of magnets that have the greatest value of the residual magnetic induction Br, sometimes denoted in reference works by the symbol Mr (Remanence[14]).
The second requirement for the choice of the materials of magnets is based on the need to provide the most possible engine lifetime under conditions in which the permanent magnets of the rotor and stator are working in the regime of mutual repulsion. At the repulsion the opposing magnets exert on each other demagnetizing impact. Practical use of permanent magnets when exposed to the external demagnetizing field is implementing in many of varieties of modern power generators and electric motors[15],[16]. At this is well-researched and theoretically elaborated a permissible mode of movement of the working point along the demagnetization curve of the magnet at changing the external demagnetizing field, i.e., the regime under which is ruled out the possibility of irreversible demagnetization of permanent magnets[17],[18],[19],[20]. Taking into account the recommendations contained in the said literature, as a material for permanent magnets should choose a material with a maximum possible value of the internal coercivity Hci and, accordingly, coercivity Hc. The best, in this respect, modern magnetic materials are the materials such as NdFeB, which can measure up values of Hci ≥ 30 kOe . The strong permanent magnets that are working in conditions impacting of external demagnetizing field are increasingly used. So, currently, intensive research works are carried out on creation of materials that provide more value parameters of Br and Hci[21].
The third essential factor affecting the choice of material for permanent magnets is the range of temperatures at which the motor has to work. Heightened ambient temperatures may also reduce the magnetization, and at a certain maximum temperature Tmax will lead to the complete demagnetization of the sample. In our case, as it will have said further, it is recommended to use the motor in stationary conditions of an closed premises, where the temperature may be in the range +(15 ... 25)°C, i.e. from this point of view, the restrictions in the choice of magnet material is practically no.
Thus, for the permanent magnets of the proposing motor, need to use materials such as Nd2Fe14B (often referred to briefly - NdFeB), i.e. materials which include metals: neodymium, iron and barium. Since the neodymium and barium are rare-earth elements such magnets are called as Rare-earth magnets[22].
The presence of iron in the composition of materials such as NdFeB determines their susceptibility to the adverse effects of ambient humidity. Rusting of iron entering into their composition, leads to irreversible demagnetization. The methods of conformal coating the surface of the permanent magnets have been developed and widely used, but it naturally leads to a further rise in price of products containing very expensive at the present time the material NdFeB.
In any case the choice of the material for magnets and the technology of manufacturing that material, the choice technology of protection the magnets from corrosion, the choice means of protection (shielding) from the interaction of magnetic fields emanating from the lateral surfaces of adjacent stationary magnets, as well as the choice of methods of fastening the stationary magnets and materials for the corresponding fittings must be carried out in close cooperation with the companies - manufacturers of magnets which advertise and provide appropriate services.
At the real designing should take into account the findings and recommendations contained in “Appendix 2...” in regard to the choice of a geometric shape, size, nature of the initial magnetization, as well as with respect to screening of the side surfaces of the adjacent stationary magnets. At this the stationary magnets providing levitation magnets of the movable loads, during their moving into sector A8 – O – a11 (Fig. 2 and Fig. 5), may be different from the form of the stationary magnets which provide an additional torque during the moving of the loads into sectors: a12 – O – a16, a1 – O – a3 and A4 – O – A7 (Fig. 11). They may be more narrow, and only the first of them (left) must have the cut of the left upper corner (as it is shown in Fig. 5 and Fig. 11).
The final form and parameters of the stationary magnets should only be determined by results of experimental testing of the device.
To eliminate the mutual influence of the stationary magnets which are too close to each another should be applied well-known measures of the shielding of magnetic fields[23],[24],[25],[26],[27],[28]. The word "shielding" in the usual sense is understood as the creation of obstacles blocking the external influence. The shielding of magnetic fields emanating from one pole of the source is carried out not by means of their blocking from the protected object, but by means of redirection from the protected object to the side of opposite pole of the source. To do this, the side walls of each adjacent stationary magnets must be covered with a layer (or, if necessary, multiple layers) of material which is characterized by a very large value of permeability. At this the magnetic field lines are being directed along the path possessing many times smaller magnetic resistance than if they had to pass through the gap of air or other material.
At shielding of the side walls of the adjacent stationary magnets, which provide an additional torque in the sectors: a12 – O – a16, a1 – O – a3 and A4 – O – A7 (Fig. 11), it is necessary to take into account the relevant recommendations contained in “Appendix 2...”.
In Fig. 11 are shown 3 groups of the stationary magnets. Rotating of the disks mounted on the shaft of the motor is counterclockwise. This means that each “anterior” magnet of each of the groups of magnets (the left in Fig. 11) may render an inhibitory effect to approaching him the ring-shaped magnet of the movable load. To eliminate, or at least for significantly weakening this negative impact, it should also introduce the shielding covering on left lateral walls of the “anterior” stationary magnets of each of the three groups. For the right lateral walls of the “posterior” magnets of each of the three groups need not shielding.
Speed adjustment can be actualized through change (decrease) of the torque on the motor shaft. In order to realize such a possibility the engine design should include the technical means for adjusting the gap between opposing magnets, i.e., devices that allow you to remove the stationary magnets from the surfaces of the ring magnets of the movable loads. These means of impact on the magnitude of the resultant torque must allow regulate the speed of rotating of the motor shaft up to full stop the motor.
This page was last modified on 2 October 2014