Re: spindle motors

--- In CAD_CAM_EDM_DRO@egroups.com, "Carlos Guillermo" <carlos@v...>
wrote:

> Thanks Wally and Tim for the motor website links!
>
> To answer Wally's question: I am building the headstock for my
> ground-up benchtop milling machine, which has taken ALOT longer
> than expected due to various events over the past 3 years (new
> house, new baby, new job, etc....). But I'm finally making
> progress. >

> About the headstock: I'm just planning on making an R8 spindle,
> and connecting the motor with a toothed belt, on a cast iron box.
> I'm going to use a Hitachi VFD, which can output up to 600% of
> line frequency, so I'm just trying to see if I can take advantage
> of that to get extra speed for engraving, PCB milling, EDM
> electrode milling, and other low power jobs. Of course, I'm
> looking into what the bearings can take, but I also don't want the
> motor to blow up. So I guess I'm looking for a "regular" 3-phase
> AC motor, that can mechanically handle several times its rated
> speed.
>
> Carlos Guillermo
> VERVE Engineering & Design
>

I have a feeling your bearings will heat up at these RPM. And i
think you are going about it the wrong way. Engraving, PCB milling,
and EDM electrode milling are low HP high RPM. 6000 RPM is not very
fast for these jobs. Jon Elson found a simple soultion to this
problem. He made a simple spindle adapter plate to fit on his main
spindle and hold a separate small high speed motor. For a picture of
this go to Jon's air spindle page at this URL.

http://ascc.artsci.wustl.edu/~jmelson/wwspndl.html

He has a write up there that will help you.


The VFD drive is still a good idea but stay away from the 6000 rpm.


Wally K.