What is the air gap?

The air gap is the air space between thestatorcore and the rotor of the electrical machine within a magnetic circuit. In electrical machines, the reluctance of the air gap can sometimes be overlooked without committing a major flaw in the calculations, thanks to the contrast with the reluctance of the magnetic circuit difference.

On the one hand, electric motors convert the supplied electrical energy into mechanical energy. On the other hand, the electrical generator uses mechanical energy and subsequently changes it into electrical energy.

In both cases, at the moment when the stator and rotor energy exchange works at the same time, in order to produce a magnetic flux by means of copper coils that the two machines have In this process of converting energy, the air gap comes into play.

Inside the air gap, a magnetic field is formed, one of the coils is in charge of producing the flux which must move through the air gap. This must be crossed twice by each pole that contains the electrical machine for each phase.

How does the air gap work?

One of its essential functions is to provide linearity to the magnetic circuit. It is also responsible for avoiding core saturation since it is in charge of distributing the flux dispersion manifested in an air gap to a large extent.

A medida que aumenta el entrehierro, asimismo aumenta la reluctancia, es decir, la resistencia que el material tiene en el momento en el que atraviesa el flujo magnético afectado por un campo magnético del aire. El cual, por la ley de OHM magnética, el flujo tendría que reducirse, al ser una fuerza que produce una intensidad de campo magnético constante.

A very important factor is that the greater the number of motor or generator poles, the more times the flux has to cross the air gap. Another very important factor is the monitoring of the air gap in electric motors and generators, otherwise, they would cause machine malfunctions.