[iti_uk]

Hi, I posed this question on the Endless-Sphere board with one reply which didn't seem to answer my question, then nothing more. Could anyone here shed some light on this?

Originally Posted by iti_uk

Hi all.

What is the significance of the number of induction bars on the rotor of an ACIM? Is there a general rule of thumb as there is with other PM motors? Do more bars reduce cogging? Are the limitations more down to manufacturability reasons?

It seems to me that with a slipping field, number of bars would not be critical, but I'm only guessing and would like to be corrected.

TIA

Chris

Originally Posted by iti_uk

If I could further clarify my question, coming from another angle;

What would be the effect on efficiency, power, smoothness etc. if the rotor was created in the way shown in my quick CAD snapshot (attached). In this I have only shown what would be the aluminium (or copper) "bars", the void in the middle of the part being filled with laminated iron, as in a normal squirrel cage rotor. How would this work inside a 4 pole 3 phase stator? (p.s. I didn't bother drawing the bars skewed - it was a 2 min job to illustrate my question)

(Further note - I also did not draw the connecting "squirrel cage" rings at either end of the rotor. It's just an abstract illustration...)

TIA

Chris

edit:
A further thought on the idea, if I may. I have seen videos of AC motor stators spinning coke cans and the like. What I am suggesting here would effectively be a thick-walled, radially laminated can. Mad? Pointless?