Patent Application
20140070651
The brushless, ironless stator, single coil motor without laminations described in this invention uses permanent magnetic field lines co-acting with magnetic field lines inherently emanating from current carrying packets of wires to both start and run the motor.
The meaning of Brushless is that the energizing of the motor is done without any brushes, but also generally means that the energizing is done with current pulses from a circuit.
The meaning of Ironless stator is that the stator in the motor is void of any iron or ferro-magnetic material.
A single coil means that the stator coil has solely two free ends stator leads . . . energized by pulses.
Without laminations indicates that neither the stator nor the rotor has any laminations.
A plurality of wire grouped into packets, are paired by two packets, with every pair regarded as an electromagnetic field, having the same number as the motors permanent magnet fields, even though not all packet pairs might be assembled.
The stator with packets pairs are placed between two co-axial cylinders, both having attached alternate polarity permanent magnets, with the two cylinders rotating together around the wire packets pairs.
The cylinders have a common attachment to a shaft running in bearings in a motor frame.
The present motor is both Ironless, Brushless, Single coil and has no laminations.
It has unique double magnetic fields which are interacting to produce torque for start and run function. All related art electric motors on single phase current are not inherently self starting and are designed with a start function description, which also becomes its generic name.
Related art single-phase AC (alternate current) electric motors running on regular AC current are not inherently self-starting when they are turned on, but need some form of starting function.
A common electric motor in use today is the “split phase motor”; not self-starting without a start winding split from the main winding, with the start winding disconnected after running.
A “shaded pole” motor uses a separate short-circuited winding section to create a starting function; even though it has a very low start and run torque it is in-expensive and commonly used.
A “capacitor start motor” uses a separate capacitor to shift the phase angle of a winding to achieve starting.
A “permanent split capacitor motor” (PFC) again uses a separate capacitor to shift the phase angle of a winding to achieve starting, with the capacitor permanently left in the circuit.
Brush type motors such as the “DC motor” or the “Universal motor” both use a “commutator” and two or more “brushes” to achieve starting and running.
“Reluctance motors” need an electronic circuit to start and run.
“Brushless permanent magnet motors” need an electronic circuit, normally with 6 transistor's, to convert the single phase current to 3-phase current. After which the converted 3-phase current starts and runs the motor.
If the “brushless permanent magnet type” drive motor is of the 3-phase type, the number of rotor poles are different then their stator poles which means that not all the rotor poles are lining up with their stator poles, at any one time, which also results in a loss of efficiency.
Common pairings of stator poles vs. rotor poles are 6-8, 12-4, 6-4 and 6-2.
With the un-equal number of stator poles vs. rotor poles, especially if the rotor construction is of the permanent magnet type, it will also mean that all the magnetic flux from the permanent magnets, will never totally co-act with all the stator poles, at any one time, which results in a loss of efficiency.
The above stated starting devices that are presently used are costly and some are complex.
A simple starting system for permanent magnet motors would be desirable.
Other motors driven from the AC power line have speed profiles that must be related to the frequency of the power line. If the frequency is 60 hertz, a 2-pole motor runs at about 3450 RPM, a 4-pole motor about 1650 RPM, a 6-pole motor at about 1100 RPM and so on.
The present permanent motor invention does not have the above deficiencies . . . it has equal number of stator packet pairs and permanent magnet fields, and has solely 2 free ends stator leads.
In regards to the frequency limitation, the present invention does not have any limitation, it can be driven by a simple pulsed drive circuit at any speed.
The motor described in this invention is brushless, iron less, single coil and has no laminations.
The meaning of Brushless is that the energizing of the motor is done without any brushes, but also generally means that the energizing is done with pulses from an electronic circuit.
The meaning of Ironless stator is that the stator in the motor is void of any iron or ferro-magnetic material.
A single coil means that the stator coil has solely two free ends stator leads . . . energized by pulses.
Without laminations indicates that neither the stator nor the rotor has any laminations.
The motor uses permanent magnetic field lines in the rotor co-acting with magnetic field lines inherently emanating from current carrying wire packets in the ironless stator, to both start and run the motor.
The present permanent magnet motor does not have the energy loss deficiencies nor does it have the other above stated frequency limitations or deficiencies.
It has equal number of stator packets pairs and permanent magnet fields, and has solely 2 free ends stator leads from the stator, which also simplifies the drive circuit.
Each of the permanent magnets is always assembled into its plurality of specified number of poles on the rotor, with each of the magnets regarded as a separate permanent magnet field, co-acting with the same number of stator packet pairs.
For each said permanent magnet field, a plurality of wires are grouped into packets, pair of electro-magnetic packets pairs are generally assembled into its stator assembly, even though the motor might not have all the corresponding packet pairs totally assembled, with some spaces for the packet pairs left empty.
Even though the remaining packet pairs always are connected continuously and terminating solely in two free stator lead ends,
The advantage of partial assembly is three-fold:
The motor manufacturer can assemble motors of different torques on the same frame, different speeds on the same frame and saving both in material and assembly.
In addition, it can give the motor customers their required speed characteristics without building a more powerful motor and then limit its speed with PWM (pulse width modulation). It reduces the weight of the magnet wire, again with a reduced material cost and reduced assembly cost.
As an example, a sixteen magnet rotor can have only a single wire packet pair on its stator, but the 16 magnet rotor would still receive 16 power pulses from the single “packet pair's” two free stator ends, energized from the normal drive circuit, (and its synchronized drive current pulses) according to commands from the rotor position sensor which senses 16 magnet poles. Because of the present inventions unique construction this combination is possible, with the possibility of having other numbers
Such as 16-1 (a one pole motor), 16-2, 16-3 . . . 16-16.
The added number of power pulses, within its limits, is a benefit as stated in common motor formulae:
“Torque=poles×flux×turns×volts/resistance”
The number of poles is recognized as a power enhancer, gives added power pulses and greater torque even with other motor parameters being equal.
A related art 2-pole common motor has power pulses every 180 degrees; a 4-pole motor has a 90 degree power pulse, a six pole has 60 degrees . . . and so on.
The present invention can have any number of power pulses depending on its construction. Of course, the number of packets could be divided into separate sections for multiple speed control. Another benefit would be that the number of wire packets could be suited to achieving the total stator resistance/inductance, an important factor when 230 or 277-volt operation is called for, without having to wind with a very small magnet wire diameter or gauge.
With both rotors locked in an angular relationship on a common shaft, it is designed where the outside rotor is having alternate polarity magnets and the inside rotor is having alternate polarity magnets with exactly the same number of poles.
The angular relationship is such that a North pole on the outside rotor is directly in line with a South pole on the inside rotor. This is creating a toriodal-like continuous magnetic flux lines configuration wherein the outside first North pole's flux lines goes into a wire packet (situated between the outside and inside magnets) then going into the inside rotor's South pole, and, at the same time that the inside rotor's North pole's flux lines are going into the outside rotor's South pole (again through the adjacent wire packet), and so on, with all the North pole's and all the South pole's magnetic flux lines emanating from all the magnets on the two rotors enhancing each other, all, in unison.
The enhanced flux lines and fields, so created, enhances the torque created in all the stator's wire packets according to Faraday's induction law.
These enhanced flux fields and torque effects is also both the start and run power in this invention. The spacing between the two rotor's magnet's and the depth of the packet between the magnets, for best torque efficiency, can be calculated using the square law of magnetic fields which states:
This calculation can also include the optimum air gap between magnets and packets.
The wire winding of the packet's can be wound directly on a winding drum or frame or can be pre-wound and later assembled onto a mounting drum or frame. The drum can be made of heat-conductive aluminum or die-casting's, for heat sinking (with insulation), or, it can be made out of insulating material such as thermo-set plastic or other types of plastics.
The packet pairs can have more then one embodiments as shown
From a starting point the packet goes to the left then up, then right, then up, left, then up . . . and so on. The packet arrangement shown in
The many packet pairs with its 2 free stator ends, hereafter called A and B, are normally pulsed with a current pulse that moves the rotor and its magnets to a new position.
If the current pulses are making the A end positive and B end negative, the rotor responds by assuming a new position, which is sensed by a rotor position sensor, that signals a simple drive circuit to reverse the current, making A negative and B positive. The rotor responds accordingly with another advancement of the rotor to achieve start function and run function, with the possibility of the rotor running at multi-thousand RPM (rotation per minute).
If the number of packet pairs and magnet fields are great enough, the motor of this invention can be made to run directly on alternating current (AC) without a pulsed drive circuit. Common frequencies of AC are: low frequency, 50 Hertz, 60 Hertz and 400 Hertz.
The start frequency which would make this motor start and run directly on AC can be calculated from: Hertz, rotor and load inertia, rotor diameter, magnetic flux field, ampere-turns and bearing quality.
In addition, it is a known fact that the flux lines emanating from a magnet's front face are greater if the magnet's back face is mounted on a soft iron or steel plate.
The present invention is utilizing this fact by mounting both the outside rotor's magnet's and the inside rotor's magnets on a soft iron cylinders or stamped “cans”.
For economy, and of course reduced torque, one of the magnet assemblies could be eliminated and replaced by a simple iron plate.
This new motor design, which eliminates so-called iron laminations, which are used in the majority of electric motors today, is therefore less costly and uses less materials.
Another saving is that the necessary insulation of laminations by epoxy coatings or insulating plastic tabs are not now required.
It is using only two rotating soft iron cylinders with magnets, spaced around packets of wires, is of simple construction, yet is as efficient or more efficient then the above listed motors.
When a related art motor is using laminations in a permanent magnet motor a resulting interaction causes torque pulsations, also known as “cogging”.
The present invention having no laminations and no iron in the stator and is therefore totally void of cogging and interaction of iron and magnets. Furthermore the parasitic Eddy current losses and induction drag that are inherent in the related art salient pole lamination-type motors and generators does not occur in the present design.
The pulses for driving the motor can be DC (direct current) or AC (alternating current) or DC current derived from rectification of AC plus a smoothing capacitor.
It is combining an energy-efficient motor with design simplicity, to get the motor customers a very versatile product with many speed and torque options, yet still being an in-expensive and compact solution.
It could be described as:
An ironless, brushless, single coil motor without laminations, with magnetic-field start and run comprising: an ironless stator, brushless, single coil motor without laminations, having a rotor with two coaxial cylinders both mounted on a common shaft journalled in bearings on a motor frame, both cylinders having a plurality of alternate polarity permanent magnets mounted on the coaxial cylindrical walls facing each other, paired with north south magnets on one wall and south north magnets on the other with every said pair regarded as a separate permanent magnet field, between said facing walls a non-rotating stator having a plurality of wires grouped into a plurality of adjacent wire packets pairs, with every said pair regarded as a separate electro-magnetic field, with permanent magnet fields and electro-magnetic fields having equal numbers, with the wire packets pairs having a substantially rectangular, close-spaced form in the axial direction and a curved cross section, with wire packets connected continuously and terminating solely in two free stator lead ends, connected to a drive circuit which is synchronizing alternate current pulses into all the wire packets at timing commands from a rotor position sensor, wherein the electro-magnetic flux field, caused by current in the wire packets, is co-acting with the permanent magnetic flux field inherent in the permanent magnets, in unison, to start and run the motor.
Unique features:
Current carrying wires formed into packets, will create magnetic flux lines when current is introduced into the packets. They are emanating concentric flux fields according to the statements below. The larger the number of individual wires grouped into a packet the larger the electro-magnetic flux field.
This motor can have a very high stacking factor . . . also known as fill factor or copper fill.
If there are nearby permanent magnets, there is also a co-acting between the permanent magnet flux field and the electro-magnetic flux field. This is in accordance with the known law of induction, sometimes referred to as Faraday's law or Ettinghausen's effect:
All electric motors are using these effects, but the present invention is using these effects in both a better and different mechanical relationship and an toroidal-like induction relationship. Text books are using theoretical and experimental results to establish certain rules which are also used in the description of the present invention. 1. The common description that magnetic flux lines is emanating from the North pole of a magnet towards the South pole is also used here. 2. A circular magnetic field exists around any current carrying conductor, and if many wire conductors are organized into packets, the magnetic field is multiplied by the number of conductors in the packet. 3. If two packets are closely spaced with one packet carrying current “up from the paper” and the adjacent packet carries current “into the paper” an electro-magnetic field is established having both a north pole and a south pole. (see Exhibit “X” and “Y”.)
Also refer to
The co-action of permanent magnets flux fields and flux fields from the wire packets are pictorially described in
In the present invention the current carrying packets of conductors in the magnetic field will cause either the conductors to move out of the magnetic field or the magnets to move away from the conductor. As a corollary, if either the conductors or magnets are moving in relation to each other, a current will be generated in the conductors, and becomes a generator.
To describe the unique design and construction of the present invention please refer to
It could also have a number of curved magnets segments instead of a ring.
On the left side of
In the middle of
When the current reverses, in all the packets at the same time, a strong repulsion exists, followed by a strong attraction for all the next angular packet pairs, that exists at the periphery of the motor, and the rotor moves with great torque.
On the right side of
The packets can have different winding arrangement. Referring to
On the stator drum 70 in
The above summary is not intended to describe each disclosed embodiment or every implementation of the present invention. Figures and the detailed description, described herein, is not intended to limit other embodiments.
A coaxial soft iron cylinder 40 with an attached magnet ring 50 is shown inside cylinder 20. Again the magnet poles can also be attached to the cylinder 40 as a number of magnet segments. As an alternate embodiment cylinder 40 would consist only of soft iron with the magnet ring 50 being eliminated.
Both co-axial cylinders 20 and 40 are mounted on a shaft 60.
A cylindrical stator mounting drum 70 is showing a plurality of packet pairs 80 that are all interconnected with connections 90 between the pairs and are terminating solely in two free stator lead ends 100 and 110. The lead ends are also marked “A′ and “B”.
A representative bobbin 85 is shown on one of the packets.
A plurality of mounting pins 105 on the stator drum is securing the stator drum onto the drive circuit 160. One representative such pin is shown at 105. These pins also could also provide electrical connections from the stator drum 70 to the drive circuit 160.
The two co-axial cylinders 20 and 40 has openings to provide air ventilation on the inside of the motor. One representative such opening is shown at 25.
A rotor position sensor 150 is located on the stator and a drive circuit 160 is on a motor frame 120, The motor frame 120 has bearings 130 and 140 for the central shaft 60.
The spaces between the packet pairs can be left empty or be filled with a bobbin or spacer 85.
The soft iron cylinder 20 with attached magnet ring 30 and cylinder 40 with attached magnet ring 50 is shown through-out in this figure with dashed lines as an indication were the magnet rings changes polarity.
The magnet assemblies could also use separate magnet segments instead of magnet rings.
The soft iron cylinder 40 is shown with attached magnet ring 50.
The packet pairs are shown with a plus sign and a central dot sign indicating how the packets are wound with adjacent pairs having a reverse wind direction. Between the pairs is an bobbin 85 or a spacer.
The magnetic flux lines shown on the left side from North pole to South pole between the two coaxial magnet assemblies are shown with flux lines between the North pole to South pole aiding the electromagnetic flux lines emanating from the packet pair.
This aiding or enhancement of the flux lines continues throughout the periphery of the motor in its plurality of magnet pairs and packet pairs as explained in the description.
A magnet flux field change is indicated at 300 causing the rotor position sensor 160 to signal to the drive circuit 170 to change pulses from positive to negative. 160 and 170 are shown in
The angular change over point can be accomplished by adjusting the rotor position sensor mechanically, or, adjusted by electronic means.
On the right side of
On the stator drum 70 in
It could be constructed by taking the cylindrical parts and laying them flat.
The magnetic cylinders would be laid out flat on a u-shaped frame 170 carrying both a top magnet assembly 180 (20) a lower magnet assembly 190 (40) with packets 200 (80) all mounted on a wall structure 210. The magnetic interaction in the linear design is substantially the same as the cylindrical structure for performance and power production if the flux field level and the pulse level into the packets would be about equal.
To aid in a uniform cross section of the packet during the winding, a formed part 75 can be guiding the wound wires to have a uniform inside and outside diameter of the packets. Pressure or heat can be applied to part 75 or to bobbin 85 for uniformity.
A needle 76 that carries the wound wires during the winding of a packet pair 80 on the stator drum 70 is also indicated as rotating in a uniform circle at the approximate centerline 77 of the packets. The part 75, also on the centerline, is used as a guide for a more uniform and centered winding of the packet pair 80.
The above summary is not intended to describe each disclosed embodiment or every implementation of the present invention. Figures and the detailed description, described herein, is not intended to limit other embodiments.
