Kingfish wrote:The problem with parallel traces though is that the current will never balance, so instead I thought of running the turns in series through the layers for a higher count, and then each stator is in parallel
Kingfish wrote:Adding one more stator-rotor pair increases the output (F) by roughly √2; not quite 50%
Kingfish wrote:Toying with a heat sink idea: Wouldn’t a couple of layers of solid copper work to pull heat from the board so long as I didn’t fill the center of the windings?
liveforphysics wrote:You need to make use of every bit of copper available. If it's a 6 layer board or something, each layer needs to be as thick of copper as they make, then you need to figure out how many turns you're going to need (which is going to be a lot with no core if you want to have reasonable inductance), and then you need to make every layer as thick as physically possible to get the number of turns in you need. Anywhere you made it less thick would just be additional resistive loss and heating in an area that is all ready going to be nearly impossible to cool. The concept of balancing thickness between inside and outside layers is fundamentally flawed, you need to just do anything possible to reduce copper losses, and the layers should all be parallel. The ones that heat up faster will increase in resistance and get less of the current load naturally.
Thud wrote:Glad to see you working in this thread again.
Kingfish wrote:The one good thing the book does discuss is that they are claiming multilayer printed ink boards (why don’t they just call it PCB?) are superior in performance over Litz and monofilament/ribbon winding, and two-layer PCBs as well owing that the multilayers act as parallel strands (Eric, take a bow).
Kingfish wrote:Case 1: Back Iron material set to high permanence M-15 and adjusted the thickness until the saturation is about 2T. The airgap registers about 0.6T.
Case 2: Back Iron thickness reduced, saturation is about 3.5T. Airgap registers little change.
Case 3: Back Iron material changed out to Iron and the saturation climbs to 5.5T. Airgap now registers close to 0.7T.
Case 4: Reduce the thickness so that the saturation measures 8T. Airgap measure 0.75T.
Case 5: Push the model until saturation is about 10T. Airgap measure 0.8T.
-- compute the force
Lorentz = mo_blockintegral(11);
Force = mo_blockintegral(18);
bearing wrote:Something has got to be wrong with your model. Maybe the properties of the iron materials are wrong. Seems like it never saturates. When the backing iron starts to saturate, the airgap flux should get weaker.
Kingfish wrote:I am still looking for a good answer on calculating material saturation; it's like this big secret - deathly silence when asked.
Kingfish wrote:According to the help manual on Page 93, mo_blockintegral(11) = "x (or r) part of steady-state Lorentz force", and mo_blockintegral(18) = "x (or r) part of steady-state weighted stress tensor force".
Should I be looking at other integrals?
bearing wrote:Did you define boundary conditions? How much air is there around the motor?
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