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- เผยแพร่เมื่อ 12 ม.ค. 2022
- More electric powertrains are transforming the automotive industry, from Mild Hybrid systems which typically use use radial flux electric motors to control ancillaries such as pumps, fans and provide some torque assistance and regenerative braking to full electric vehicle drive trains.
This video has been created to explain the key different types of permanent magnet motor and how they differ.
We look at how radial flux motors work and compare radial flux vs axial flux motors. We also look at internal rotor vs external rotor radial flux motors.
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This was a great breakdown. I came looking for info on axial motors, and this really gave some good info. thanks!
Brilliant, really pleased that it was helpful! There is lots of potential for Axial flux motors in new applications
Great explanation been serching for a visual to understand better. Im subscribed.
Awesome, thank you!
I just would like to say thank you for making this video. While I dont understand the equations or know how to use them it finally gives me some grounds to work towards in regard to designing my own electric motor for an EV. On that note though, do you have a video breaking down the formula for a dsir motor? That would be immensely helpful on giving me grounds to prototyping my motor in CAD. Thank you.
Glad it helped, we don't have that on a video sorry. These are relatively complicated machines to design due to the 3D magnetic flux. Most design packages can only design in 2D so you need to convert the geometry into a 2D radial approximation to do simple calcs (basically a pair of larger diameter radial motors with an equivalent active surface area.
Finally seeing a sizing equation being used for comparison of E-machines on YT :). Question: at the initial diameter the length of the radial macine was chosen as to equal the torque/power for the axial flux machine with the same diameter and then was keet constant for the comparison at other diameters. Second question: for the axial machine the axial length is also kept constant, but the aspect ratio I believe also has a second order efect on torque/power sizing equation, right - is that taken into consideration ? A reference for the study/report where the charts come from would be nice
Hi thanks for the question and sorry for the slow reply. Please find a link to an old paper where this relationship was first described. pdfs.semanticscholar.org/71ed/336bb0a934ac3ccf92397deb6a3497e6e84f.pdf
It is a simple geometry feature of the active magnetic area being on the faces of the machine rather than the internal diameter so the active area increased d^3 rather than d^2
Somehow the subscribe button does not show and yes a great video thanks for sharing 🙏🏻🙏🏻🙏🏻🙏🏻
Thanks for the comment!
@@etech49 Thanks a ton for reply dear friend please change TH-cam settings su that we can subscribe to your channel dear, great work
2:55 - now I know why my electric scooters use this kind of motor.
Nice
Thanks for the comment!
Fantastic video. Please give some examples of external rotor motors (ERPM) and external rotor axial motors? Also, what college does research in this area of external motors and external axial rotors?
Hi Eyenor, we know you connected and got an answer already from @Ryan but we are putting his reply here to hopefully help others as well:
DC motors have several issues for use in a variable speed application like an EV traction system they did used to be common if you look back at old trains and teams. But ultimates eliminated because of the issues. Brushed machines suffer from wear and have loses associated with the excitation and very poor speed/torque control. BLDC is common in applications like ancillary drives, it is too coarse for traction and is effectively 3 phase anyway!
For ERPM radial look at Protean motor drive, or the model drone market advantage is simply greater relative active surface area in air gap and mechanical advantage placing the air gap further away from the rotating axis. But these machines are very hard to make reliably!
For dual rotor single stator axial Yasa, Magnax, and Emrax
For single rotor my old business Avid, now Turntide or Heinzmann
This is a great video! I'm doing some market research for an investment group that is evaluating a new manufacturer of axial-flux electric motors. Apparently, this company has developed some novel manufacturing techniques. I'm trying to learn if their products are commercial viable. Is this something you might be able to offer insights on?
Hi Alex, it certainly is please connect with Ryan here and send him a message: www.linkedin.com/in/ryan-maughan-a2893610/
3:05 Similar to a Small Quad copter / Drone motor, Yet they dont have magnets attached to the stator in the center like this, just the ones in the bell housing that spins. Would having larger motors with dual sets of magnets like this produce more thrust?
A drone typically uses an external rotor motor, where the stator is inside and the rotor is outside, like this th-cam.com/video/HSd8Xp7OIh0/w-d-xo.html This has the advantage of more mechanical advantage, so more torque for lower speed motors. But inner rotor allows you to spin faster and get more power density, which is good if you can use a reduction gearbox.
Hi, nice video. What is length of radial flux motor in graph at 7:00 minutes?
It would be longer than the axial flux, and it was also held constant through the comparison. The reason the relationships vary as they do is because of the active surface area. If you think the surface area of a cylinder 2πrl excluding the end faces for radial and surface area of the end faces for axial 2πr^2 its really a geometry play of how much active surface you can get in.
thanks, But I did not get it! Why should be cooling in ERPM more difficult?! when it is automatically cooled by air convection ..
In air flow you get contamination including moisture, dirt and dust which must be dealt with for a reliable long life application. For more power dense motors air cooling is not enough. You must have liquid cooling to the stator at least which is more difficult when it is mounted inside the rotor to get a good effective pathway and surface area.
Excellent presentation, congratulations 👌.
You forgot to present the functioning of the new generation Brushless Hybrid Fast - Rotation Motor (BLHF-RM) four-phase synchronous motor, which I have already tested quite well, both with latent and prominent poles. I invite you to my section on TH-cam.
My engine can also operate in the regime of increased power and torque based on the multi disc system (Axial System) 😀.
Thank you
we are working on a generator design and require some assistance. how can we connect?
Hi sorry for the slow reply, this one slipped under the radar. You can connect with Ryan here: www.linkedin.com/in/ryan-maughan-a2893610/
Hello, for your opinion what is the best of this motor technology for high power applications (high power short time). I am developing a motor (not for commercial just a university project) the goal of the motor is to have the most power at peak (10s) peak for 30s and for 2min continuous power doesn't need to be high.. the size is about 30kg (250mm*250mm) but can vary a lot.
This all comes down to the application and thermal management. The limiting features of any motor are the ability to generate magnetic repulsion force in the air gap and the heating effect that accompanies this in both the rotor magnetic circuit and the stator. With the thermal limit of the materials being the key.
For a high peak power you need the ability to create a big magnetic force for a short time. This needs a large electrical current and to limit the rate at which it heats the other parts of the motor, as well as a strong rotor magnetic field.
There isn't a simple answer and you could make a design of either radial flux or axial flux, for very short peaks the thermal mass of the motor components is more important than overall ability to cool. But this tends to not be desirable in most applications, unless its for a stationary machine!
@@etech49 it is for a racing motorcycle
@@etech49 thanks a lot for you reply I appreciate very your fast response.
Axial flux exterior rotor with complex control 👌I will need 2 per car. One 3 phase ac and one dc.
Thanks for watching, we would recommend using a pair of AC motors with a speed controller that converts the battery DC into controllable 3phase AC
Koenigsegg's Quark "raxial flux" motor boasts very high power density by "increasing rotor diameter against the bulk of the stator and optimizing the stator OD (outer diameter) to be able to accept this extra flux.” By doing this it also allowed the motor to use "this radial flux to augment the main axial flux".
Do you think this is just fancy marketing and they just really increased the magnetic face surface area of the rotor permanent magnets? I struggle to see using this description where radial flux would come into play here.
Generally in an axial flux motor there is unused end winding area in the radial direction, they seem to be utilising what was the end winding to form an additional active magnetic area.
@@etech49 does Tesla use radial motor ? If they do, why don't they use axial flux motor to increase acceleration for higher performance ? Since Mercedes bought yasa, they must be using axial flux design for their future cars...
@@ps3301 All Tesla models, and all EVs of any brand with significant production volume, use internal rotor radial-flux motors. The motor is a small part of the EV, in terms of volume, mass, and cost, so there is not much to be gained by a motor design change.
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hello
Hello to you to, we hope you have enjoyed our content about electric motors, EV’s and more!!!
not very disruptive our motors are so good they are made of plastic and do not get hot, are 99+ efficient from 7 rpm, match that
That’s impressive and you will do very well with that technology if your claims can be proved.
The purpose of this video was to help people understand more about different types of existing motor though, not show an innovation or new idea this is meant to be an overview of existing established tech 👍