Homebrew PCBs

JanRwl@... wrote:
> In a message dated 1/18/2003 6:17:44 AM Central Standard Time, 
> twb8899@... writes:
> 
> 
> 
>>Several types of spindles were available but I used the 60,000 rpm 
>>drill/route spindles on the EX-200 and 80,000 drill only spindles on the 
>>other machines. The air requirements for these machines was about 20 cfm at 
>>90 psi.
> 
> 
> Tom:  
> 
> TWO points:  60,000 and 80,000 RPM?  Were these "high frequency" motors, or 
> "brush motors"?  TEFC, I would assume!
> 
> WOW, 20 CFM at 90 PSI!  That would keep a 10 hp compressor running possibly 
> over 50% duty-cycle!  Wouldn't it?
> 
> Jan Rowland
> 


I haven't seen these motors running my self, but I know they carry a 
hefty price tag (secondhand AUD$2500) and suck a lot of juice. I 
learned this when I was shopping around for a PCB spindle for my home 
made manual drilling machine. They need a variable frequency variable 
voltage 3 phase power supply (voltage is proportional to speed because 
of back EMF). I think the guy selling them said they run up to 250V at 
full RPM. They can use precision ball bearings under 100,000 RPM and 
air bearings for higher speeds. I did not buy one of course. Check the 
following link.

http://www.westwind-airbearings.com/

Adam