Values of flux densities vs frequence in induction motors

[zlatkodo]

The values of flux densities ( in air gap, back-iron and teeth) for standard three-phase, squirrel cage, LV motors are important data in the winding data calculation in each rewindshop. Empirical data from existing designs are commonly used.
It is well known that the used values of flux densities for todays 50 Hz motors are approximately 5% higher than for 60 Hz motors.
But what are these values for other frequencies (for example, for motors intended for the processing of wood which are supplied from the rotary drive 200 / 300 Hz)?
Has anyone made the comparison between the results of core-calculation and the existing designs of these motors ( please, note that this is not about a motors fed from the VFD)?
Zlatkodo

 

[electricuwe]

I'd assume that the main target in choosing flux density is to get an acceptable level of iron losses (based on cooling and efficiency cosniderations).

For higher operating frquency you may either use standard laminations operated at significanly lower flux or special laminations (usually thinner and with higher Si-content, therefore more difficult to handle and to cut).