Hummina Shadeeba
1 MW
Ianhill said:For a cleaner back emf ?
For a easier rolling system ?
For less wear on the bearings ?
For an easier rolling system. For less current needed to produce the same unpowered “coast”as a non-cogging motor. And also I believe the cogging torque is present at all speeds so less power needed to overcome that resistance at all speeds
What I’m hoping someone can show:
Is cogging a loss of momentum for starters?(seems obvious in that it does)
Is cogging due to iron losses and most likely hysteresis?
I believe a skewered stator produces less torque ripple AND less cogging torque. A cogging motor takes more current to coast unpowered than a lower cogging motor.
if u are still unsure of the questions read them again and if u have no evidence maybe someone who knows can tell
An easy answer would be hysteresis but I haven’t seen that in my little searching. Not that that means it’s the case. That’s why I’m asking.
“ Cogging torque produces zero net-work”
https://upcommons.upc.edu/bitstream/handle/2117/99998/MASTER%20THESIS.pdf?sequence=1&isAllowed=y
Maybe that means the loss of momentum must be attributed to iron losses.
it makes sense that a slotless motor would have greater hysteresis as it has more iron that is being exposed to the switching field and therefore should have MORE cogging...if cogging were a result of hysteresis