Position of a Resolver on a Servo Motor

Think of a resolver as a rotary transformer... it has a primary winding, or the "excitation" winding and 1 or more output windings. The phase shift between the input and output windings is normally fixed... rotating the rotor will change the phase shift. It is the measurement of this pahse shift that is used to determin rotational changes.

So... if you hold the rotor and rotate the stator about the rotor, the same effect is present.

http://en.wikipedia.org/wiki/Resolver_(electrical)