Learning Forum

[sree-ranjini.kizhakkethil-swaminathan]

What is the difference in defining stacking factor in saturation and in active length of MOTORCAD? Which method must be followed under what circumstances?

[Bo Ren]

Hello Sree, 

Stacking Factor Calculation In Motor-CAD has three types, which are 

Ignore Stacking Factor - no account is taken of the stacking factor.

Stacking Factor (axial length) - the axial length of the machine is reduced in the FEA calculations to account for the stacking factor.

Stacking Factor (saturation) - the BH curves for the stator and rotor steels are adjusted to take into account the stacking factor.

 

Stacking Factor (saturation) theory

An equivalent homogenous material with the same properties as the entire stack is created.

The equivalent permeability of the homogenous material becomes:

μeq = kst x μiron + (1 - kst) x μ0

The magnetic flux density of homogenous material for specified magnetic field becomes:

Beq = μeq x Hiron

where

kst = stacking factor

μiron = permeability of iron

μ0 = permeability of free space

μeq = permeability of homogenous material

Beq = magnetic flux density of homogenous material for specified magnetic field

Hiron = magnetic field

The employment of the stacking factor consideration methods in Motor-CAD depends on the simulation needs. The default setting is recommended.  

Thanks 

Best regards

Bo REN