mid-range instability was Re: Allegro 2961 uptdate

Hello,

First, I'll assume you are not trying to make decisions based on
unloaded motors...

Lanchester dampeners are the "classic" solution. These consist of a
viscous fluid contained in a housing around a metal disk which is
driven by the motor (often the 2nd shaft is used). The additional
damping provided by this "raw egg" spinning reduces/eliminates the
resonance.

Good machine design will also help. Very often motors are sized
incorrectly for the load and speed needs of the system. I'm guilty of
trying "what I have" instead of always calc'inc the correct motor for
the intended use. ALL the major motor mfrs. have motor "sizing"
software freely available. If you are not using their motors you will
need to cross reference to what you intend to use...

Thirdly, and related to the above; the simple addition of friction to
the machine drive assembly may help.

The BEST way to deal with mid-range resonance is to use good machine
design, AND use a drive (like the Geckos' ) which have been designed
with the reduction of this problem in mind...

Hope this helps.

Ballendo

--- In CAD_CAM_EDM_DRO@y..., lonnietoons@y... wrote:
> I have tried changing some things but no help.
> Does anybody know any tricks that help with this mid-range
> instability?
> Lonnie