Inertia Calculations for Bearings in Rotor Assemblies
Inertia Calculations for Bearings in Rotor Assemblies
(OP)
I am doing rotor interia calculations for some rotor assemblies in a brushless DC motor. In the past I have always ignored any effect due to front and rear bearings. I am beginning to question this assumption. Does anyone know if this a valid assumption, and if not, some insight on how to calculate the values?
The bearings in question are standard radial bearings in which the inner race is fixed to the rotor shaft and the outer race is fixed to the outer bearing journal.
Thanks for any input.
The bearings in question are standard radial bearings in which the inner race is fixed to the rotor shaft and the outer race is fixed to the outer bearing journal.
Thanks for any input.





RE: Inertia Calculations for Bearings in Rotor Assemblies
But I bet you could find some software to help you.
Good Luck its not an easy one.
RE: Inertia Calculations for Bearings in Rotor Assemblies
RE: Inertia Calculations for Bearings in Rotor Assemblies
In my point of view we can take into consideration as follow:
first look at the rotor inertia I(r) along rotating axis
then look at the inertia I(b)of both inner rings of bearings along that rotating axis as an addition elements to the rotating system. Since inertia is proportional to rotating speed then by looking at the percentage of bearings inertia contribution, I(b)/I(r)the assumption is evaluated. It's better to take a look at the Inertia formula to come up with the general idea of how much a geometric element ( ring, non-axis symmetry for example)contibute to an axisting rotating body to justify our assumption.
I hope I'm right.
Good luck.
Tan Bui