The magnet sectors drawn in red in your Fig 14 - what do they represent?
Eric, you have an attentive eye sir! TÃ¢â‚¬â„¢was caused from a bout of laziness and drew only the unified pole (2n) for simplicity: Represents single poles.
The triple layer of 24 AWG wire looks like it would work out well. Depending on what Kv you want to achieve, you could connect the layers in parallel and get approximately the same current capacity of the single 20 AWG, but with 50% more turns.
I think that makes for a great talking point that strangely circles back to a problem that I had right near the beginning of the thread Ã¢â‚¬â€œ and it's an issue that we have to address before continuing:
The Inductance (L) calculation for a single row spiral-winding aka a flat Archimedes spiral one-wire deep is given as:
- L (ÃŽÂ¼H) = A^2 * n^2 / (8 * A + 11 * w)
L = Inductance, measured in micro-HenryÃ¢â‚¬â„¢s (ÃŽÂ¼H)
A = Average radius of the coil*, m
- Given as
A = [((OD Ã¢â‚¬â€œ ID)/2) + ID] /2
OD = Outside Diameter
ID = Inside Diameter
w = diameter of the wire
Now however we have a multi-row winding Ã¢â‚¬â€œ the intention being three sets of distinct turns rather than one wound coil which uses a slightly different formula to determine Inductance (L).
- I agree that deciding on Series or Parallel will make a performance difference. The factors that I struggle with however are that parallel inductors could suffer from eddy currents at higher frequency:
- Do we need to worry about this, and if so when does the frequency begin to assert negatively?
- The second issue is that I had a problem determining the correct value for Inductance (L) given the Wheeler formula.
- of what use is L to us in the balance or design of the circuit, and how does this affect our ControllerÃ¢â‚¬â„¢s FET stage?
- Should it be the providence of the Motor to be compatible with traditional controllers, or should the FET stage accommodate a wide assortment of motors?
- It is a question of ownership: Which unit is responsible for compatibility?
OK, letÃ¢â‚¬â„¢s give that a serious review then, however IÃ¢â‚¬â„¢d like to save it as the desert with the cherry on top after we sort out the remaining design issues.
Thud: Chain stays vs. Torque Arm; Yeah that makes sense. The whole interface would require review, and I think that a non-wire-spoke rim would be best off the top of my little solar-powered propeller-beanie cap. We must save this discussion though because it is definitely worthy of exploration.
For now though, we have to finish the Math.