DESIGN OF OPEN SOURCE STRAIGHT PERMANENT MAGNET MOTOR

This paper deals with the attraction and repulsion properties of the magnetic field of permanent magnets in order to produce reciprocating motion in a member of magnetizing material. The essential idea of this work have started by putting a string of eight magnets type (Nd Fe 35) spaced by equal spaces placed on the axis between two series of same magnet type each string consists of nine magnets pieces spaced apart vacuum. Series of internal and external were organized with different opposite polarity north and south that created a series of free movement of internal series between the two external strings. First of all, designed magnetic motor rectal movement consisting of two fixed (for external strings) and one moving part (Series Interior) analysis was done and its operation was analyzed. In addition, equations that describe the magnetic field arising from the moving part were modified by using two-dimensional computer model. The (femm) program was used for modeling the distribution of density, and DS Solid Works program to study and calculate the magnetic flux density, field strength and torque generated.


INTRODUCTION
Today when energy is so expensive, it is not hard to drum up interest for most any avenue that offers a breath of hope or way of escape. Magnets have enormous importance in the modern world. It would be hard to imagine life without their contributions in today's products. Automobiles have several hundred magnets from motor to sensor applications. Consumer electronics utilize them to generate video, sound and record; Computers wouldn't exist; and many high (RPM) instruments used in surgery and dentistry. The main purpose of magnets is to help in the conversion of energy: Mechanical to Electrical, such as in generators, sensors and microphones Electrical to Mechanical, such as in motors, actuators and loudspeakers Mechanical to Mechanical, such as for couplings, bearing and holding devices [1].
What exactly is a permanent magnet ? what length time does the current need to be in the coil to make the magnet ? how long can the resulting magnet support its own weight against gravity? How long human can support his own body weight against gravity before he get tired ?if someone can't do it ,how come the magnet can? These questions made the inventors interested with free permanent magnet motor since more than forty years ago.some of them made the first step of this field and others had shared with this work. some of the inventors are: I-Charles J. Flynn, 1995 His work relates to a method of producing useful energy with magnets as the driving force and represents an important improvrment over known constructions and it is one which is simpler to construct.can to be self starting. Is easier to adjust,and is less likely to get out of adjustment, the present construction is also relatively easy to control, is relatively stable and produces an amazing amount of output energy considering the source of driving energy that is used. The present construction makes use permanent magnets as the source of driving energy but shows a novel means of controlling the magnetic interaction or coupling between the magnet members and in manner which is relatively rugged,produces a substantial amount of output energy and torque, and in a device capable of being used to generate substantial a mounts of energy [2]. II-ShenHe Wang,1997. He has designed and built an electrical generator of five kilowatt capacity. this generator is powered by permanent magnets and so uses no fuel to run.it uses magnetic particles suspended in a liquid. The motor consists of a rotor which has four arms and which sits in a shallow of liquid which has a colloidal suspension of magnetic particles in it. Outer fixed Cylinder has eight N pole Magnets. Inner rotating Cylinder has Six poles Magnets. Magnetic Shielding is used to create N pole only. By adjusting the alignment of the N pole magnet ,slight rotation of the Inner cylinder will allow the magnetic repulsion to keep accelerating the inner cylinder -energy can then be extracted [3]. III-Harold E. Ewilgg, Chandler: Russell R. Chapman; David R. Porten both of Mesa, all of Ariz, 1997. A simple electrical generator powered by parmanent magents alone.this generator can also be used as a motor. The construction is not particularly complicated.it uses an arrangement where permanent magnets. Are associated with every second coil set around the rotor.operation is self-powered and the magnet arrangment is clearly defined.and the physical arrangment of the device is not particularly complicated [4].

IV-George Soukup, 2009
His a magnet motor has built on the "V" style of magnet placement which has two sets of permanent magnets.this style of magnet arrangment has a locking point where the swicth from wide spacing to narrow spacing occurs and this causes the rotation to stop there.the taper is much less pronunced with an inner gap some four times greater than the gap to the outer ring. it also appears that the last inner magnet has a greater gap around the drum than the remaining ring of magnets. The housing has considrable clearnce for the drum and magnets. The rear shaft bearing is just set into the back of the housing.the positioning stator magnets allows the motor to overcome the normal sticking point of the typical V -motor arrangement [5]. V-Dietmar Hohl, 2010.He uses 20 mm diameter round neodymium magnets 10 mm thick, stacked in pairs in the stator. amagnetic gate arrangement built on a flat piece of Medium-Density fibreboard 30 mm thick. The holes drilled in it are 20.1 mm in diameter and positioned so as to take two of the 10 mm thick magnets stacked together.the holes are drilled at an angle of 63° to the horizontal or 27° to the verti cal.on one side of the board, the inserted magnets have their North poles facing upwarards,while on the other side of the board,the magnets are inserted with their south poles facing upwards.his design using angles magnet pairs ,the number of magnets needed is quite high.for single V ,There are 58 magnets. for a 2-V version,116 magnets.the motor power is liklely to increase as the diameter increases as the lever arm that the magnet has to turn drum,increasesdouble the diameter to double the power [6].

Permanent Magnet
Two basic types of magnetic materials are soft magnetic materials and hard magnetic materials. Hard magnetic materials are referred to as permanent magnets because once magnetized they tend to remain magnetized. Permanent magnets are used as field source components in a wide range of products including consumer electronic equipment, computers, data storage devices, electromechanical devices, telecommunications equipment and biomedical apparatus [7]. The resource crisis of rare earth materials has broken out in motor industry in the world. The resource of rare earth material is uneven distributed in the globe. The price of these materials is raising high and high strategically. Nowadays, many of electric motors use rare earth permanent magnet for the source of magnetic field [8]. In order to configure the magnetic circuit, an operating point has to be set that will determine the energy transferred from the magnet to the gap. Consider an idealized magnetic circuit where the magnetic permeability's μr of the soft magnetic materials are infinite so that their reluctances can be ignored. Since the sum of MMF's in the circuit equals zero, the line integral of the magnetic field along the path of the circuit becomes [9]: Hm Lm = -Hg Lg (1) Where : Hm is the magnetic field of the magnet in −1 , -Lm is the length of the magnet in m, -Hg is the magnetic field of the gap, in −1 , -Lg is the length of the gap in m. Also, as stated by Maxwell's equation V_B = 0, flux is continuous as it does not have a source or sink, therefore the total flux in the magnet can be equated to the flux in external space: Bm Am = Bg Ag (2) Since in the air gap Then (2) becomes Then Bm/Hm = − lg (5) The quantity Pg = o Ag / lg is termed the permanence of the air gap. As seen in the previous derivation, the ratio Bm / Hm is only dependent on the geometry of the magnetic circuit. Fig. 1 illustrates the second quadrant of a permanent magnet's BH curve. Directly identifiable are the aforementioned quantities Br and Hc. However, once the geometry of the magnetic circuit has been established and the reluctances calculated, a load line needs to be drawn, to identify the operating point of the device. The load line typically intersects the BH curve and has a slope Bd=Hd, as previously mentioned.
As seen from the equation, the slope of the load line is only dependent on the geometry of the magnetic circuit. However, since the air gap in linear motors and actuators is of variable dimensions, the load line will also vary, unlike with other magnetic circuits, such as that of a loudspeaker. Bearing that in mind, the engineer needs to design the circuit in such a way that the load line is steep enough, so that the magnet is not prone to demagnetization effects; in the latter case, the operating point of the circuit is not close enough to Hc as needed for a large sinusoidal signal to demagnetize the magnet. At the same time, to make good use of the magnet's capabilities, the operating point has to be close to the point where BH = (BH)max, in order to extract maximum energy from it. In a practical situation, however, it is safe practice to account for the magnetic flux leakages and the finite magnetic permeability. Two new quantities are introduced, namely the leakage coefficient K1 and the loss factor K2 [10]:- K2 = (7)

OPEN SOURCE DESIGN
Before advancing into practical aspects of this design, the underlying theory has to be addressed first. In this section, the mathematics underlying will be derived in the design of the open source motor.

Mathematical Description of the open source
Suppose a bar sample is magnetized by a field applied from left to right and subsequently removed. Then a north pole is formed at the right end, and a south pole at the left, as shown in Fig. 2-a, the H lines, radiating out from the north pole and ending at the south pole, constitute a field both outside and inside the magnet which acts from north to south and which therefore tends to demagnetize the magnet. This self-demagnetizing action of a magnetized body is important, not only because of its bearing.

The idea of Open Source Permanent Magnet Motor
Initially, the idea was to permanently mount the magnets on a straight parallel shaped base. However, it then became apparent that there is a necessity of making the protype as flexible as possible.
First In this work we have used parallelogram magnets with arrangement by putting twelve magnets in two rows with length with different polarity to create a magnetic track by sending pieces of magnets sliding with length of (20cm) moves between the two rows of straight magnets. The magnets had got very satisfactory movement.  Secondly, it was began by taking each two parallelogram magnets in two rows and arranged by changing the distance between them and sending a slide of two parallelogram magnets between them. Notice the North and the South Poles are reversed on the magnets, then observe the magnetic flux lines between them with (Vizimag) package, as illustrating in Fig.  4.  This will not happen when we arrange the magnets in a circle, the circle does not have a first and last magnet. If we look closely at the middle magnet, we can see what will happen inside the circle. If the magnets on the right and the left are stationary and the magnets on the middle are allowed to rotate, the magnets on the right will begin to push the magnets on the middle away. the magnets on the middle will begin to attract to the magnets on the left. then the magnets on the left will begin to push the magnets on the middle away. the magnets on the middle will begin to attract to the magnets on the right. Fig. 6 illustrate two layers of stationary and moving magnets, each magnet on the middle is moving through different positions.
Notice that there was never occur any lines of attraction between the two layers.This is because the lines of repulsion are always greater than the lines of attraction. The moving of free magnets will be easy and smooth and fast.

Geometry
The purpose of the open source motor is to induce a torque on the rotor, via a magnetic field gradient. In practice, a continuous gradient as implied by the expression dB=dθ, is possible only with a circle permanent magnet. The flux density seen from the rotor magnets as the rotor rotates 2π radians would then resemble very closely to the trend of circular ship, in the case of an Archimedean circular. The aforementioned magnetization pattern, however, is not cost effective. Instead, it was decided that the magnetic field gradient could be assumed continuous by placing permanent magnets of two sizes in a circular stator and rotor arrangement as follow.It was decided that the magnetic field gradient could be assumed continuous by placing numerous permanent magnets of small enough size in a straight arrangement as desired in Fig. 7. However this would inevitably lead to a B versus θ. The only workaround to get a good approximation to continuous gradient was to increase the number of density of magnets and therefore reduce the spacing between adjacent magnets ,in order to get a higher spatial resolution.

Permanent Magnet Material Selection
A specific grade of Neodynium Iron Boron (NdFeB Goe) material was used to provide the magneto motive force of the inner and outer stages, namely N35. Initially, it was considered wise to employ NdFeBGoe magnets in the outer and inner structure. The wide commercial availability of NdFeB Goe magnets made it possible to purchase magnets of decent dimensions and BHmax at a relatively low cost. Appendix (A) lists the magnetic properties specific to that grade (NdFeB Goe) which was made by (OeMag) company in china.Appendix (B) shows the sample of N35 magnets with two sizes (14*30)mm & (12*30)mm. The belts of outer and inner parts of a straight base made of steel on which the permanent magnets can be attached. Also, the core consists of plastic rod which magnets can be placed. The magnetic properties of the steel were unknown ,therefore measurements had to be carried out. The material was available in two sizes namely outer (stator) and inner (rotor). The magnetic measurements for the magnetic materials were carried out using a permeameter. The purpose of a magnetic measurements is to extract the magnetic properties of a material, such as coercively Hc, remanence Br, point of saturation B, and maximum permeability μr (max). This information can be extracted the B-H loop of the measured material. In addition to the sample the permeameter involves an induction coil for the measurement of the flux density B inside the sample. And a Hall prob for measuring H produced by the electromagnet at the point where B is picked up by the induction coil as shown in Fig. 8 below.

Fig. 8. Schematic of measurement system
The DVM records the voltage across the coil wound around the sample, and feed it to the PC, which will in turn calculate B. The gaussmeter directly measures H at the point where B is measured. A digital to analog (D to A) converter is used to connect the PC to the power supply. A General Purpose Interface Bus (GPIB) is used to connect the gaussmeter and DVM to the PC. Fig. 9 shows the pareameter for induction coil and the magnet. Appendix (C) illustrate the experimental setup. The modeling of the flux lines for the suggest design which used ( Vizimag ) package can be represented by the Fig. 10-a represents the movement of free magnets on the straight slides with number of magnets steps when open source was a straight and Fig. 10-b represents the steps of free magnets on the free rotor with number of magnets steps when open source was a ring (cycle) shape.

Straight Permanent Magnet Motor Simulation
At first, the initial mesh was designed in (DS Solidworks package) consistent with the straight parameters chosen previously as shown in Fig. 11.

Fig. 11. Straight permanent magnet motor initial mesh
The mesh with 23705 nodes was then imported into (Infolytica Magnet) and a static 2D simulation was performed on both outer (stator) and inner(rotor) the distribution of flux lines is sketching with (femm), so that the magnetic field gradient can be computed. Fig. 12 shows the simulation of straight permanent magnet. The steps of inner (rotor) movement inside two outer(stator) are illustrated in Appendix (D). One of these results is the distribution of flux density as shown in Fig. 13.

CONCLUSION
The magnet of (N35) is made with low cost therefore the energy is between 263 -287 that mean it easy to broken ,so the magnets must be fixed on core with glue to prevent its damaged.
The core of stator and rotor are made from non-magnetizing and insulator material to reduce remanance of magnetism or generating the eddy currents.
The sixteen outer magnets are placed with skewing angle =15° between the two magnet's ends, that mean different poles. This angle was chosen to prevent the loss attraction which represented by negative sign. while the eight inner magnets are placed with skewing angle (θ=30°) between each two ends or different poles. This angle was chosen to prevent the loss attraction which represented by negative sign,that means the angles less them will reduce the force to zero and the rotor tends to return to its previous position where it will experience equilibrium. Therefore, at the end the result of simulation was positive for all reading from 1-19.This angle depends on the result of simulation that shown in Figs. 11 and 12. in addition to the position angle the direction of inner magnets is opposite to the outer magnets direction. In this work, a Straight Permanent Magnetic Motor was designed and its operation was analyzed. Equations described the magnetic field gradient seen by the inner part (rotor) were developed. Parallelogram shape had been replaced with Cylindrical shape of magnets because the affect of edge of parallelogram was appeared on the movement of free magnets, this conclusion explained at Dietmar Hohl, 2010 because the result torque of his motor had changed from negative to positive then return to renegative values.his problem was the flux density of the edges.
A two dimensional computer model of the motor was designed in order to perform a magnetic analysis. The magnets (N35) were examined practically with pereameter to calculate the B-H values and with (DS Solidworks ) package to calculate the torque and speed.

FUTURE WORK
After completing the computer simulations to determine the torque and speed, a control system can be set up. The reason for that is to be controlled the starting and braking of the Straight Permanent Magnetic Motor and speed controlling at all time.