I'm researching options for 2.2kw spindles, both manual and ATC. These 2 question frequently come up from others in the same boat:

1) Which is better for machining aluminum - a 2 pole spindle at 400Hz or a 4 pole spindle at 800Hz?
2) Does the 4-pole spindle develop more torque?

This article is enlightening:
https://www.anttilehikoinen.fi/techn...good-bad-ugly/

Bottom line - 'Poles ARE NOT gears.' You need characteristic curves for the spindles you are looking at. Generalizations will likely get you into trouble in lieu of legit test data.

It's not hard to find torque and power curves for any of the 'Name Brand' spindles on the market: Colombo, Teknomotor, Mechatron, HSD, Elte, Hitec, et al. I have no clue why most of the 'Chinese' manufacturers don't supply this data on their websites or along with their seller descriptions. The few curves I've come across for the Chinese spindles are so straight/linear that it makes me wonder if they are made-up vs based on dynamometer testing. Maybe everybody or nobody is cooking the books on their numbers, but I'm not about to drop $$$ on a spindle that doesn't have legit data.