# Is there a motor design where a rotor gradually moves into a stater?

I was wondering if there is a motor/generator design where the rotor moves gradually in and out of the stator along the axis of rotation, or the stator over the rotor. If so, I'd like some resource(s) to read more about it. The application I have in mind is for a wildly variable load like a wind turbine. If this is a bad design, pleas briefly explain why. Thanks in advance.

That actually exists and it's applied in magnetic levitation (maglev) trains. It's called linear induction motor (LIM). LSM if it's synchronous.

The rotor is addressed as "slider" here because it doesn't rotate.

It's in Spanish, but use Google Chrome translator.

A Study of Non-Symmetric Double-Sided Linear Induction Motor for Hyperloop All-In-One System (Propulsion, Levitation, and Guidance)

Woo-Young Ji 1, Geochul Jeong 2, Chan-Bae Park 1, Ik-Hyun Jo 1, and Hyung-Woo Lee 1

And some formulas here:

Hyperloop Transportation System: Control, and Drive System Design

Jawwad M. Sayeed Deperatment of Electrical, Computer, and Software engineering University of Ontario Institute of Technology, Oshawa, Ontario jawwad.sayeed@uoit.ca Ahmed AbdelRahman Deperatment of Electrical, Computer, and Software engineering, University of Ontario Institute of Technology, Oshawa, Ontario ahmed.abdelrahman@uoit.ca Mohamed Z. Youssef Deperatment of Electrical, Computer, and Software engineering, University of Ontario Institute of Technology, Oshawa, Ontario mohamed.youssef@uoit.ca

And the Hallbach Array:

Hyperloop Transportation System: Control, and Drive System Design

Jawwad M. Sayeed Deperatment of Electrical, Computer, and Software engineering University of Ontario Institute of Technology, Oshawa, Ontario jawwad.sayeed@uoit.ca Ahmed AbdelRahman Deperatment of Electrical, Computer, and Software engineering, University of Ontario Institute of Technology, Oshawa, Ontario ahmed.abdelrahman@uoit.ca Mohamed Z. Youssef Deperatment of Electrical, Computer, and Software engineering, University of Ontario Institute of Technology, Oshawa, Ontario mohamed.youssef@uoit.ca

• Thank you for your answer, but I'm not sure this is quite what I'm talking about. Assuming this is a generator, I mean a motor design where the primary motion is rotary, and this rotary motion is moved into, or out of a stator slowly to a fixed position so that more or less electricity is generated by the rotation. – Dan Apr 17 at 17:52
• Maybe that exists, but I don't know of that. Controlling the gap you can control the energy generated, I reckon. – user20096 Apr 17 at 20:10