[kreutz]

I am sorry for my mistake talking about low speed torque. Servo motor's continuous torque at low speed curve is slightly better than torque at high speed (but never near the stall torque figure). Torque curves from your motor's manufacturer include a safe operating area (generally at 25 degrees Celsius) and an intermittent work area. Operating your servo in this intermittent area is safe as long as is for a short time so it doesn't overheat. Continuous torque de-rates vs temperature.

Servo torque vs speed performance is highly dependent on the driver too.

By the way, the servo motor's brake feature is intended to be used only as a safety mechanism so the load will not move when not energized. It is not intended to be a braking mechanism to reduce speed. The brake mechanism will deteriorate if overloaded too.

[scott wiggins]

Any updates???

[rokag3]

hello scott,
yes there is updates
watch this splendid servo driver for big servo (UHU/Kreutz)
by the way very first time i see Mr kreutz making a mistake (about low speed torque) he was probably very tired this day, because this guy have a real knowledge about servo
http://www.cnczone.com/forums/showth...14217&page=120

[dan_the_welder]

Ok,

I am manually using my lathemaster while I figure out my cnc scheme and I have some thoughts.

Can you spin an unpowered stepper at lathe headstock speeds?

I am thinking you could use the stock motor and index pulse for threading and then shut down the spindle and use the stepper as the virtual index plate for live tooling applications.

Also does anybody have an idea about where to start looking for info about doing "parametric turning" which I believe is the term for cutting polygons, i.e hex heads and squares and stuff on a lathe?

I have seen some pretty fancy stuff cut on the high end turning centers via Youtube videos.

Dan

P.S. I like the Slant Bed idea. I was thinking about that too. Making some wedges and angling the lathe about 45 degrees. it would allow for a front mounted turret and still allow access.

[skmetal7]

Ok,

I am manually using my lathemaster while I figure out my cnc scheme and I have some thoughts.

Can you spin an unpowered stepper at lathe headstock speeds?

i wouldnt try it, you could burn out the windings, put unnecessary strain on the bearings, or burn out the controller with back emf. you could try an overrunner clutch, or a one way bearing, you would only go one direction with the stepper though

[psch3]

Hola amigos!


On the motor, check out my DC treadmill motor conversion. It works great and its cheap. Similar to what a lot of guys do on the smaller lathe. These machines just don't need the horsepower of an AC motor, and it's very cheap to be able to find a variable speed motor controller and treadmill motor on eBay.

The other possibility if you choose the DC motor is to put an encoder on it and make it a servo. This would let you index the spindle, attach live tooling (i.e. a drill) to the tool holder, and do some pretty cool things.


BW

Hope I am posting this in the right spot. I ve been searching this forum high and low and this is the closest thing I ve found. How would you do indexing with a treadmill motor? I have the treadmill motor I am still looking into a DC drive (probably KBIC ). What controls the indexing is where Iam lost ? I thought the DC drive only controls the speed and CW and CCW rotation. Does Mach 3 control the indexing? What else besides the motor, drive, encoder, and Mach 3 would I need? This is too index a mill spindle for tool changes if it makes a difference. I am just lost on what tells the motor to index without it being a fullblown servo with an encoder on it. Thanks for any help or info in the right direction.

[Al_The_Man]

You can't index a spindle motor for C axis unless it has servo capability, using encoder and suitable drive.
The KIBC et.al is just for velocity control.
Al.

[BobWarfield]

Hope I am posting this in the right spot. I ve been searching this forum high and low and this is the closest thing I ve found. How would you do indexing with a treadmill motor? I have the treadmill motor I am still looking into a DC drive (probably KBIC ). What controls the indexing is where Iam lost ? I thought the DC drive only controls the speed and CW and CCW rotation. Does Mach 3 control the indexing? What else besides the motor, drive, encoder, and Mach 3 would I need? This is too index a mill spindle for tool changes if it makes a difference. I am just lost on what tells the motor to index without it being a fullblown servo with an encoder on it. Thanks for any help or info in the right direction.

Wow, that's a blast from the past, LOL.

That post was inspired by this article:

Converting an Ordinary DC Motor to a Servomotor

As all mentions, you will need an appropriate servo drive for your DC treadmill motor as Mach3 and a non-servo drive are not enough to drive the indexing.

Cheers,

BW