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Air gap — What is it and why is it important?

Publication date: 
November 2017
Chuck Yung, EASA Senior Technical Support Specialist
Type of media: 

Air gap is the physical gap between a rotor and stator core in an AC machine, or between the armature and fields / interpoles in a DC machine. The role of the air gap is not as simple as it appears.

Topics discussed in this article include:

  • Important principles (magnetic force and the amount of current to drive flux through air)
  • Air gap in AC machines
  • Air gap in DC machines
AC motors
DC motors