Recent content by dognotdog

So, I tinkered a bit more, now looks like: With these performance numbers for a 200mm rotor:   targetRPM 6000.000 RPM windingCrossSection 50.000 mm^2 coilTurns 10.000 - phaseInductance 0.425 mH emfPhaseInductance...

I've been toying with the concept of liquid cooled conductors in a coreless PM motor, in the shape of 2x3mm copper tubing. From a thermal point of view, it seems like a 30mm length water cooled length of that tubing (my example length) can sink about 7W of power, putting power density at over...

Heh, editing madness :) Anyhow, so 320W for all 24 poles sound about right for a solid, if the copper is 30x10x5mm? The Wikipedia infinite sheet approximation is 10x that, quite frankly I haven't a clue what's even the right ballpark for this figure. And as for the 50mm^2, that's just the...

Yea, if it was solid, but that's just the alotted space, the number of turns in that space would depend on how one would adjust the voltage/current balance, right? Seems like if I put the numbers in the wikipedia formula, solid copper would result in over 3.5kW of eddy current dissipation for...

So, I made a SAGE worksheet for this, though it seems like you have to login to see it, so here's a text version: meanMagneticRadius = 0.075 magneticFieldStrength = 0.5 magnetHeight = 0.03 numPoles = 8 numPhases = 3 windingCrossSection = 50.0e-6 windingCurrentDensity = 4.0e6 targetRPM = 6000...

Duh! Thanks! You're spot on with the torque, I wasn't seeing the forest because of all the trees! If I had paid attention to the units, like was beaten into me in the physics lectures, I might have caught onto this silly mistake! With the corrected torque, The power becomes ~1.1kW mechanically...

So, I'm checking the design of a motor for an EV, as a sort of feasibility study while I decide what to do with my broken car. Some numbers don't seem to add up, so if anybody spots any mistakes, I'd be very thankful. I'm an EE, but I've not had to compute this stuff for an electric motor since...