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Axial Air-gap Induction Motors


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I will be pleased to hear from LMPForum members who have any information relating to the theory, characteristics, design, construction, production of 3-phase AXIAL AIR-GAP (as opposed to radial air-gap) INDUCTION motors up to 2-3 kW power rating.


The main advantage of this kind of motor to our (potentially high-volume) project is its flat (like a pan-cake) construction (i.e. its short axial lentgh compared to its diameter).


Ultimately, I need a low-cost motor manufacturer (anywhere in the world) who already has such motors in its product portfolio.


Most small-motor manufacturers in the Far East would say "We can design and make such a motor for you. Just tell us what you want!", but they have never produced axial air-gap induction motors before (i.e. they do not have such motors in their product porfolio).


Before I can tell what I want, I need to know more about and particularly experiment with (test/evaluate):


a 3-phase star-connected 230V AC (line-to-line) axial air-gap induction motor of

~1kW power rating, preferably with a high number of poles (e.g. 8 poles or more).


This could be a rotor-stator-bearing set or a fully enclosed (e.g. IP54) motor of probably single-rotor (rather than double-rotor) construction.


Any information (advice, references, links, contacts etc.) will be much appreciated.


Many thanks in advance.




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Hi Errol,


Welcome to the Forum.



Please note that you have posted your inquiry in the segment devoted to Variable Speed Drives.


Since your question has nothing to do with Variable Speed Drives, please allow me to advise that the


correct segement for your inquiry would be AC Machines.


By posting in the correct segement, it makes it easier to search on a subject at a later point in time.


I've asked our administrator to remove your post from the Variable Speed Drives segment and to move it to the AC Machines segment. Please look for it there.... and of course, any subsequent replies.


Kind regards, and we look forward to your future participation.

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Have you done a GOOGLE search on PANCAKE MOTORS yet ?


If you have, you will have seen the below reference from powertransmission.Com: (click on underlined link)

Something else you might consider adding to your specificaion:

  • Inverter Duty or Sinewave power
  • Mechanical Load: Constant or Variable Torque
  • Minimum Speed
  • Maximum Speed
  • Load Inertia
  • Accel / Decel Requirements; i.e. time in sec. from what speed to what speed
  • Shaft length & Diameter
  • With or without feet

A few decades ago, I was involved with Louis-Allis Pancake motors that drove the slitter knives in a Mill Paper Roll Rewind Slitter applicaion. The motors were mounted on a bar along the face of the paper roll and could be moved axially along the face of the paper roll to obtain the reqired slit widths. Motors were 5 HP and were operated from a 30 kVA PWM Inverter to speeds up to 6000 rpm (2-pole design).


Louis-Allis as a motor company of yesteryear no longer exists so I don't think they are a viable consideration today.


I used Google to search on Pancake AC Induction Motors, and received the below response to my search: (click on underlined text to activate link)

Hope this helps.

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Dear Errol,

I've had contacts with some manufacturers of pancake motors in past years, since 1980.

I've seen that almost all interesting applications need something special (hollow shaft, heavy-duty bearings, special dimensions, etc.) this should be the reason why such motors are not so common as standard motors.

Manufacturing of special steel stator is possible with a variable pitch punch press, winding is not a problem.

1-side motor should be a problem for efficiency, but you don't mentioned your application.

What is your "high-volume"? 1.000, 10.000 or 100.000 ?

For high-volume applications you have to select a special embedded motor, not a standard motor.



Mario Maggi - Italy - http://www.evlist.it - https://www.axu.it

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