Re: [CAD_CAM_EDM_DRO] Re: Running a BOSS on single phase

Polaraligned wrote:

>
>Thanks Jon. I knew you would know. I just wanted to avoid spending
>the money on a rotary converter when this machine is eventually (soon)
>to be upgraded. I have called all my local motor rebuilding outfits
>and have failed to find a used 3 phase motor. I would not mind investing
>in a rotary if this is something that I can get some use out of in
>the future on both of my bridgeports ( and maybe an American made
>lathe, If I can find one reasonable priced!). I have a static converter
>on the one BP and am pretty happy with it. All everyone on the BP list
>talks about is using VFD's. Both my BP's are variable speed so I
>guess the VFD would not help me out anyway. Don't they have a big torque
>drop off at the slow speeds?
>

No, the torque holds constant down to zero speed. But, of course, a
belt-type
vari-speed drive, as on the 2J, multiplies torque as you slow down. The
only
advantages you get there are smooth starting, silent operation when the
spindle
is off, and electronic braking when you stop the spindle, as well as the
conversion
from single-phase to 3-phase. I've never had a rotary converter, and
now that
I've used a VFD, I'd never want one!

> I feel sad to gut this BOSS without
>at least playing with it a bit to appreciate how far technology has
>come in the last 25 years.
>
>

Well, you could come up with one or more transformers with the same
output voltage
as the Bridgeport's transformer, only plain single phase. Then, it
should work. You'll
also need to convert any onter power supplies to 120 or 240 V. I guess
you coulr
run the rest from a 240-208 V autotransformer. I hope it doesn't blow
any driver
transistors in the first couple hours of operation!

Jon