why are EV DC propulsion motors all series wound?

[jim leuba <leuba@cncrepair.com>]

Dear EV list readers:

I need an EV education.
Where can I read a technical discussion on propulsion motors?

DC motors with a separate field could easily provide regen.  Is there an
efficiency loss when it is a motor (comparing separate field to series
field)?  With field weakening, a separate field design has a wide (and
energy efficient) speed range. 0-4000 rpm.

Where are brushless 3 phase AC (rotor is a magnet or electromagnet)
propulsion designs?
I read in the newspaper that GM uses a AC motor, made here in Dayton,
OH.

My business is repairing CNC servo drives.  I am familiar with DC and AC
spindle motors and drives.

Jim Leuba
leuba@cncrepair.com
http://www.cncrepair.com