On Mon, 7 Dec 2015 18:07:24 -0500, "Jim Wilkins"
wrote:

"Ed Huntress" wrote in message
.. .
On Mon, 07 Dec 2015 15:53:05 -0500, wrote:

it's got permanent magnets in it, it is DEFINITELY a DC motor

Well, if one wants to get fussy, small AC synchronous motors also
are
made with permanent-magnet rotors. But there is a starting issue and
some other complications that suggest this case is not one of those.

--
Ed Huntress

The Segway uses three phase AC motors with extremely strong permanent
magnet rotors.
http://www.urbandharma.org/udharma5/segway.html

-jsw

They are 3 phase brushless DC motors. They wouldn't run worth crap on
3 phase AC current.. They are electronically commutated. The 3 "phase"
4 quadrant controller can control the rotation of the motor to within
a few degrees, so you get instant response to balance the SegWay.
Same basic technology used in powered wheelchair motors and a lot of
e-bikes but with a high ratio reduction gearbox.