Is an angle grinder motor a permanent magnet motor or not ?,
If it's mains operated probably not. Get a screwdriver, take it apart and find out.
Indeed - ac motors tend to create their own magnetic field with an opposing coil.
do you think i can use it as a power source for a wind turbine ?
As lemonie says ....often...
you need to tell the ac coil where the magnets in a dc motor would be to be a magnet for the other coil to generate electricity. i.e. you need to excite that coil with some power, in order for the other coil to see a magnetic field and extract energy from the turbine.
It's complicated - but really not impossible.
(switch it off first...)
Oh cack! I hope he hasn't taken my advice and not turned it off first.:(L
Call the local A&E;, ask if anybody has been brought in slightly singed, with a screwdriver embedded in their forehead...