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  1. L

    Tesla's Model 3 motor technology.

    Probably means PM assisted synchronous reluctance (not switched reluctance).
  2. L

    Angled Stator Laminations vs Rotation Direction

    "Angled laminations" are usually called "skew." The stator or the rotor can be skewed. The main reason this is usually done is to reduce cogging torque. It has no effect on direction of rotation.
  3. L

    New motor design

    Not sure why he uses force instead of torque but it doesn't really matter for the point he is making. The 2 force vs angle graphs are a bit different than the standard ones you generally see in the literature but the bottom graph is force vs current vector phase angle with respect to the d-axis...
  4. L

    Magnet motor?

    nutspecial, The physical law it is breaking is the conservation of energy. You can't get more energy out of a system than you put into a system. In the first video you posted, notice that every one of those parts of the video where motion is produced, a human is in some way providing energy...
  5. L

    Magnet motor?

    I suppose if you started physically moving the magnets while it rotated, it could work. But then you are adding energy into the system, which defeats the supposed point of the magnet motor. What advantage do you think doing it this way would have over normal motors?
  6. L

    Magnet motor?

    Magnet motors are literally impossible. If you had a motor that had permanent magnets on the rotor and the stator, then the most the rotor will turn is 1/2 revolution. It will turn until the magnets are in a state of equilibrium. Actual motors work because at least on of the magnetic...
  7. L

    Motor Design Software

    Typical software used in industry would be MotorSolve, Speed, RMExpert, JMAG-Express, and YES motor design software. There are others, but those are the main ones I've seen. A lot companies develop their own software. And, of course, in addition to this motor design software, most companies...
  8. L

    PM Motor theory - formulae etc.

    If you pair an ideal motor with trapezoidal back-emf with an ideal trap drive and do the math, you can see that the harmonics in the back-emf and the harmonics in the current actually work together to produce torque, not losses. In fact, if you compare an ideal trap motor+drive to an ideal sin...
  9. L

    FEMM Help needed

    Well, it depends what you are trying to do but generally you will group the entire rotor into one group. Then you can select the group and then go up to "Rotate" under the Edit menu. The angle you need to rotate it for each step is going to depend on a number of things (number of poles, number...
  10. L

    Asynchronous motors - is induction the new future?

    An active research topic in academia is the design variable flux-intensifying machines. See this abstract, for example. These are IPM machines that use magnets with low coercivity so they can be more easily demagnetized and remagnetized. I spoke with a professor at the U of Wisconsin...
  11. L

    Coil Winding Show - Chicago - Oct 4-6

    For those in the Chicago area,the Coil Winding show is coming up soon (Oct. 4-6) and you can get tickets for free. Besides seeing a whole bunch of cool technology used to manufacture motors, you can also attend talks by Konstantinos Laskaris (Principle Motor Designer at Tesla), Jim Hendershot...
  12. L

    Stupid Me

    It isn't quite right to say that the only thing that causes torque is amps. Torque (in PM motors) is caused by the interaction of the permanent magnet flux with the flux caused by the current flowing in the coils. So torque is proportional to 1) the current, 2) the air gap flux (per magnet...
  13. L

    FOC/Field Oriented Control

    That lecture is by Dave Wilson at TI. For a more in depth look from Dave, look up "Teaching Old Motors New Tricks" on youtube. It is a set of 5 lectures that really goes into detail. It has some of the same material as this one.
  14. L

    Polymagnet - programmable printed magnets?

    I talked to these guys at a conference a couple years ago. That had a lot of different magnets to play with at their booth. I asked if they had any ideas about how these would be used with motors and they didn't give me much of an answer. At the time, they were somewhat limited on the grade...
  15. L

    Resources

    Electric Machine Design Videos by Jim Hendershot. http://www.motor-engineer.net/engineering-center/learn/tutorial-electric-machine-design-hendershot/ I've taken a course with Jim and see him at conferences every once in a while. He's a great guy and these lectures are a very valuable resource
  16. L

    Windings: basic questions.

    One last question, because I'm' genuinely curious about your reasoning, then I'm done. I won't even reply to your answer. If you truly believe back-emf is bad and should be minimized, why would you use 52 turns? Why not 1 turn?
  17. L

    Windings: basic questions.

    Browser, I'm going to finally take your advise and stop replying to you. Good luck with your 1 turn, low voltage, high current motor.I hope it does what you want it to do.
  18. L

    Windings: basic questions.

    You are forgetting about the back-emf. V = IR + E. 100 V = 10 A x 0.5Ω + 95 V. That's a pretty elementary mistake to make, IMO. For real motors, the back-emf waveform is calculated and then confirmed with testing. This is not the best way ... you will not get accurate results. The way...
  19. L

    Windings: basic questions.

    Your insistance that back-emf is a bad thing and needs to be minimized is preventing you from understanding why a single turn isn't the best way to wind a motor.
  20. L

    Switchable KV

    If you have a motor with windings for the field and armature (series DC motors, shunt wound DC motor, etc.) instead of permanent magnets on the field as brushless motor are, then you essentially have a motor that can have adjustable Kv. Provide less current to the field winding and Kv goes up...
  21. L

    Windings: basic questions.

    Browser, go download Mevey's paper that Miles linked to. Go to chapter 2, equation 2.40. Same equation that I've given 3 times now. If you read earlier in the chapter to see how he got to that equation, it is VERY clear that e in his equation is back-emf.
  22. L

    Windings: basic questions.

    These aren't arguments ... all I did here was quote from some texts, hoping you'd take it on their authority since you've ignored everything else I've said so far. Apparently not. Go read through the derivations and you'll see that your addition of the word "negatively" is ridiculous. E is...
  23. L

    Windings: basic questions.

    It's been a while since I've read Mevey's paper ... good call, Browser could learn a lot from it. One of the things he would learn from that paper (or the books I mentioned, for that matter) is that the back-emf in a motor is just the derivative of flux linkage with respect to time. And we all...
  24. L

    Windings: basic questions.

    Seriously, pick up Kingsley and Fitzgerald's Electric Machinery. It's a standard textbook for the first course you would take as an undergrad in electric machinery. They go through the derivation of energy conversion starting from the law of the conservation of energy to models for different...
  25. L

    Windings: basic questions.

    He hasn't even thought it through. If you have diodes on the three legs then in a Wye connection you will get zero current and in a delta connection you might possibly get current to flow through 2 legs but there won't be any commutation it will just lock into place and you'll have a nice heater.
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