HET Electric Motor Massively Boosts Power, Torque and Efficiency, Reduces Weight and Complexity
08/10/2019 2:02 PM
Linear Labs makes some enormous claims about its innovative electric motor design: two to five times the torque, three times the power, 20 percent greater efficiency, less complex powertrains, no gearbox required(Credit: Linear Labs)
..."The HET is a three-dimensional, circumferential flux, exterior permanent magnet electric motor with some interesting characteristics. For starters, it runs four rotors where other motors typically run one or two. The stator is fully encapsulated in a four-sided "magnetic torque tunnel," each side having the same polarity, ensuring that all magnetic fields are in the direction of motion, and there are no unused ends on the copper coils wasting energy. All magnetism the system creates is thus used to create motion, and all four sides of the stator contribute torque to the output.
It also achieves field weakening in a unique way. Field weakening is used to increase motor RPM when it's already running at full voltage, by reducing the field flux – which is usually achieved by injecting extra current in an opposing direction. This current injection trades additional speed for motor torque, and reduces the efficiency of the motor. The HET achieves field weakening by rotating one or both of its magnetic end plates out of alignment, meaning that this motor can build extra speed with no efficiency loss. Indeed, overall efficiency climbs at higher speeds."...
..."Where most motors suffer from torque pulsing, or cogging, at slow speeds, which could make an electric car take off in a jerky manner, the HET is able to produce overlapping power pulses around the stator for enormous, smooth torque at slow speeds, and then change its operating patterns by grouping poles together as motor speeds increase. This almost acts like an electronic transmission, emulating six-phase, three-phase, two-phase or one-phase designs and allowing the motor to increase speed without changing its frequency, voltage or current levels."...
..."The result, says Linear Labs, is a truly remarkable motor that produces two to five times the torque density, at least three times the power density and at least twice the total output of any permanent magnet motor of the same size.
It also eliminates the need for DC/DC converters and the aforementioned gearboxes, reducing total vehicle cost and weight significantly, and the company says the motor's inherent efficiencies across different speeds, as well as the weight savings it achieves through component reduction, can draw some 10-20 percent more range out of a given battery pack."...
Looks good but we'll have to see how it plays out...interesting though...
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Re: HET electric motor massively boosts power, torque and efficiency, reduces weight and complexity
08/10/2019 4:23 PM
This sounds like a great idea, but I think they are hyping it too much. Unless the efficiency of other PM motors < 79% or so, they can't get a 20% gain.
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Re: HET electric motor massively boosts power, torque and efficiency, reduces weight and complexity
08/11/2019 12:01 AM
Really just more interested in the concept right now, the new design...it seems really different to me...and interesting...seems to have solved some inherent design flaws in other motors...but the concept of electric motors for cars is really still new in this modern resurrection movement we are currently in, so I would expect some new designs like this that are designed for purpose....
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Re: HET electric motor massively boosts power, torque and efficiency, reduces weight and complexity
08/11/2019 12:12 AM
Isn't efficiency of a device, whose purpose is to move, defined as (energy out/energy in)?
For a vehicle, the energy out could be calculated as the Range of the vehicle multiplied by the Sum of all friction forces at a given speed on a horizontal road. That sum of friction forces could be calculated from the torque required to rotate the wheels/tires..
For electric vehicles, the energy in is the energy required to charge the battery, which is easily measured by appropriate instruments.
The ratio of those two values will be the efficiency.
Such a ratio must be affected by everything in the drive train, including bearings, gears, joints, etc. Successfully eliminating any of those sources of friction, along with the accompanying reduction in weight, should increase the efficiency of the vehicle.
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Re: HET electric motor massively boosts power, torque and efficiency, reduces weight and complexity
08/13/2019 2:25 PM
Note that the comparison numbers quoted are for "torque density" and "power density", i.e., torque and power divided by volume of the motor. It's not clear whether the comparison is to conventional motors including the associated gearbox. Still a smaller, lighter motor is an advantage in that it allows for more battery capacity and range.
Re: HET electric motor massively boosts power, torque and efficiency, reduces weight and complexity
08/13/2019 2:39 PM
So the same amount of torque and power delivered from a smaller lighter footprint...for comparison, so you could add battery capacity for increasing the range, or you could match existing size to increase the power and torque....as well as other benefits such as smooth torque delivery at low rpm...
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Re: HET Electric Motor Massively Boosts Power, Torque and Efficiency, Reduces Weight and Complexity
08/12/2019 5:29 AM
<...two to five times the torque...>
That will cause the vehicle to approach wheelslip more closely, leading to handling, control and safety challenges.
Torque is what the load presents to the motor, not the other way round.
To equilibrate the system and obviate the challenges, a smaller motor might be attractive, perhaps?
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Re: HET Electric Motor Massively Boosts Power, Torque and Efficiency, Reduces Weight and Complexity
08/14/2019 5:44 PM
You bring up an excellent point! I presume there will indeed come a time when 'wires' will either be made of graphene, or will have a graphene conductive component. As you point out, when that happens, among other things, motors will become much smaller and lighter for a given power.
On the other hand, One must always take the "facts" and numbers from reporter's articles with a grain of salt. For example, in your linked article, essentially the same paragraph is repeated as two bullet items (first and third in the quote below). In the first one, it says "...its intrinsic mobility is 1000 times more conductive than silicon", while in the second instance, it says "...its intrinsic mobility is 100 times greater than that of silicon". Also, while the mass of an electron is incredibly small, it is NOT zero.
"
Graphene conducts electricity much better than copper. Graphene’s current density is 1,000,000 times greater than copper and its intrinsic mobility is 1,000 times more conductive than silicon.
Graphene conducts heat better than any other know material in thermal conductivity. Oddly, it actually shrinks when it is warmed and expands when it’s cooled. This fact makes graphene the only known example of what scientists call “an electrically conductive membrane”.
Graphene is fantastically good at electricity; its current density is 1,000,000 times greater than copper’s and its intrinsic mobility is 100 times greater than that of silicon. Electrons move through graphene with virtually no resistance and without mass. "
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Re: HET Electric Motor Massively Boosts Power, Torque and Efficiency, Reduces Weight and Complexity
08/16/2019 8:16 PM
I agree that the author is not being very precise with his terminology.
Current density is "current divided by cross-sectional area". It's not a property of a material. Carrier density is a property of a material.
Mobility is the speed that carriers (electrons) drift with a given electric field, e.g., 1 Volt/meter. Conductivity is the product of carrier density (per area) times mobility. So high conductivity can be due to high mobility, high carrier density, or both.
It's not a simple matter to measure the electrical properties of graphene since conductivity is in a two-dimensional layer and directionally dependent, and samples of graphene are tiny and delicate. One method that has been done is to deposit graphene on a quartz slab inside a waveguide. The change in phase of the reflection will permit determining the conductivity.
Re: HET Electric Motor Massively Boosts Power, Torque and Efficiency, Reduces Weight and Complexity
08/15/2019 6:09 AM
Even with the best battery and motor technology available,the country will need a complete electrical infrastructure overhaul.
It will require a lot of energy to replace all of the vehicles currently in use.
This will require charging stations,and people want fast charging,so the demand on the grid will be high,and redistribution of power will be required.
Charging stations will require large energy storage capacities to meet the needs of highly variable demand;holidays for instance.
Standardization of charging methods and connections will be necessary.
I think on-the-fly charging is a better solution,where cars are charged by coils embedded in the highway,and in cites at intersections,traffic lights,etc.
On interstates, a small amount of charge at each location as a vehicle passes over it.
Debit to accounts via up link to LAN's, WANS or satellite.
I probably will not be around to see these changes,but it seems to be the trend as I see it.
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HET Electric Motor Massively Boosts Power, Torque and Efficiency, Reduces Weight and Complexity
Re: HET electric motor massively boosts power, torque and efficiency, reduces weight and complexity
