Wondering if anyone has any suggestions for putting a variable speed
motor controller on my little 110V mill/drill. The belts are a *******
to adjust for different speeds... it would sure be nice to just turn a
dial and still get reasonably good torque w/ a reasonable amount of
speed variablility. And, I'm doing a CNC conversion soon, so this would
really be a + (especially if it has an an analog input for adjusting
speed).

I've seen a lot of Variable Frequency Drivess on ebay for 3ph stuff...
wish I had a big mill with that kind of motor... but my mill/drill will
have to do for now.

What about 110V 1ph? What kind of motor controller and who are good
sources? Is this even a good idea?

Thanks a million

Single phase squirrel cage AC motors like your 110V motor can *not* be
speed controlled. So if you want speed control, you are looking at swapping
the motor, or else going to a variable pulley. I'm not going to comment on
the variable pulley method. If you decide to swap motors, you can go 2
ways: DC or 3 phase AC. There have been lots of designs for speed controlling
a DC motor used to control a treadmill, suggest googling. A 1 hp 3 phase
motor that will bolt on may work for you, and may cost less than you think.
Suggest you start looking around your area (or posting where you are!) and
watching ebay.

GWE

stag wrote:
Wondering if anyone has any suggestions for putting a variable speed
motor controller on my little 110V mill/drill. The belts are a *******
to adjust for different speeds... it would sure be nice to just turn a
dial and still get reasonably good torque w/ a reasonable amount of
speed variablility. And, I'm doing a CNC conversion soon, so this would
really be a + (especially if it has an an analog input for adjusting
speed).

I've seen a lot of Variable Frequency Drivess on ebay for 3ph stuff...
wish I had a big mill with that kind of motor... but my mill/drill will
have to do for now.

What about 110V 1ph? What kind of motor controller and who are good
sources? Is this even a good idea?

Thanks a million

Hey, thanks... I don't have 3ph in my shop though. Will the VFD's w/
220 1ph-in/220 3ph-out work in this situation? Or, are rotary phase
converters the only option w/ machine tools? In that case, I'd just
scrap the thing and buy a full-size Bridgeport anyhow.

Thanks again...

stag wrote:

Hey, thanks... I don't have 3ph in my shop though. Will the VFD's w/
220 1ph-in/220 3ph-out work in this situation? Or, are rotary phase
converters the only option w/ machine tools? In that case, I'd just
scrap the thing and buy a full-size Bridgeport anyhow.

Sure, they'll work. - GWE

stag writes:

And, I'm doing a CNC conversion soon, so this would
really be a + (especially if it has an an analog input for adjusting
speed).

Between this and the CNC conversion, you're better off starting with a used
Bridgeport. The conversion is easier and cheaper in the end, and certainly
much more capable.

On 3 May 2005 16:27:38 -0700, "stag" wrote:

Hey, thanks... I don't have 3ph in my shop though. Will the VFD's w/
220 1ph-in/220 3ph-out work in this situation? Or, are rotary phase
converters the only option w/ machine tools? In that case, I'd just
scrap the thing and buy a full-size Bridgeport anyhow.

Thanks again...

On 3 May 2005 16:27:38 -0700, "stag" wrote:

Hey, thanks... I don't have 3ph in my shop though. Will the VFD's w/
220 1ph-in/220 3ph-out work in this situation? Or, are rotary phase
converters the only option w/ machine tools? In that case, I'd just
scrap the thing and buy a full-size Bridgeport anyhow.

Thanks again...
Not only will the above work, there are lots of cheap 3 phase motors
around. And Dealers Electric has some pretty cheap VFDs. The really
nice thing about the VFD is that it will (should) accept the command
from your CNC control. If you already know what kind of control you
plan to buy contact the seller and see what kind of signal it puts out
for speed control. Then make sure the VFD you buy will accept that
type of command.
Cheers,
Eric R Snow

And you can get a VFD that runs on 120v up to 1/2 hp.
see
http://web4.automationdirect.com/adc/Shopping/Catalog/AC_Drives_-z-_Motors/GS1_(120_-z-_230_VAC_V-z-Hz_Control)/GS1-10P5

A 1/2 hp 3-ph motor will be cheap on eBay.

Randy


"Grant Erwin" wrote in message
...
stag wrote:

Hey, thanks... I don't have 3ph in my shop though. Will the VFD's w/
220 1ph-in/220 3ph-out work in this situation? Or, are rotary phase
converters the only option w/ machine tools? In that case, I'd just
scrap the thing and buy a full-size Bridgeport anyhow.

Sure, they'll work. - GWE

"stag" wrote in message
oups.com...
Hey, thanks... I don't have 3ph in my shop though. Will the VFD's w/
220 1ph-in/220 3ph-out work in this situation? Or, are rotary phase
converters the only option w/ machine tools? In that case, I'd just
scrap the thing and buy a full-size Bridgeport anyhow.

Hi Stag,

Re the VFD, that is exactly how many are used: they allow you to BOTH
convert 1ph to 3ph AND to vary the speed of the 3ph motor (within limits).

But my question to you is: if you can afford to "scrap" the mill-drill and
buy a full-sized Bridgeport (or Bridgeport-sized mill), why would you
attempt to do a CNC conversion on the mill-drill? A CNC conversion is an
expensive undertaking, both in dollars and in labor. Frankly, I see that
investment wasted on a mere mill-drill. The inability to accurately
re-position on the Z-axis (assuming yours is a round-column mill-drill)
would be enough for me to scrap the idea of adding CNC to a mill-drill.
Other limitations would be machining capacity (the spindle-to-column and
spindle-to-table dimensions are typically limiting on a mill-drill).

Don't get me wrong, I'm not a "mill-drill basher." I have one myself and
understand why people buy them. But if you have the space for a full mill
and the disposable income for a full mill, then I would recommend buying a
full mill and then adding your CNC conversion. In the end you will have a
MUCH more capable (and valuable) machine.

Regards,
Michael