Why Induction Motor Called Roating Transformer

Like D.C motors,the a.c motor's rotor doesn't collect power  by induction in precisely the similar way as the secondary of a two-winding transformer collect power from the primary

windings.These motors known as Induction Motor.An Induction motor can be called a rotating transformer,because the primary windings of the induction motor is stationary but secondary is free to rotate exactly same as the 2-windings transformer.