then rotating the rotor by selectively exciting the coils while the tooth magnetization remains to produce {HEAD ~ a magnetic rotational force} on {TAIL ~ the rotor}; and 
on
then rotating the rotor by selectively exciting the coils while the tooth magnetization remains to produce { HEAD ~ a magnetic rotational force } on { TAIL ~ the rotor } ; and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH