A C Servos are the dogs danglers for spindles, just fitted a 12.5Kw one to my lathe, it will spin the 10 inch chuck up to 2000RPM in under 2 seconds if I want and has constant torque from 0rpm right up to 2000rpm
Hood

12.5KW  that's a lot o' bananas!

I would settle for a tad less. But that would solve my spindle positioning dilemma too. Hmmmmmmm. Sure would solve a lot of problems....... I'm also thinking about going with DC servos on the axis drives. The spindle drive and the axis drives were a gamble. I didn't have much invested in the drives and it was worth a shot to try to use the existing motors, but.......Looks like a job for EBay!

Monty

Hood,
What are you using to power that servo motor?

Regards
Fernando

Monty
 Not sure where you are but I presume the USA, so dont know what the Emco stuff sells like there but here in the UK I know a couple of people who have sold their Emco  parts on eBay and they all sold in no time for decent prices

Fernando

 I am using an Allen Bradley 2098-DSD-HV220-SE  Its a 22Kw servo drive with Sercos but I have the sercos software disabled which turns the drive into a standard drive with  Indexing capabilities.

Hood

I just bought a 7.5 hp yaskawa spindle motor and drive on eBay. 0-8000rpm constant torque with positioning. Anybody know what rpm the spindle bearings in this lathe might be good for?? It would be nice for smaller parts to be able to go higher than 2500rpm quoted in the book. I'm not sure if the limitation was the spindle or the drive. I do know the thing is smooth as silk at 1700rpm with the current motor.

I also decided to stick with steppers rather than DC servos. If I upgrade to servos, I'll go with AC units. 

I misquoted my rapids in a previous post. In one of my typical episodes of mental flatulence, I had not calibrated steps/in yet . Rapids with the 5 phase motors are more like about 40 in/min which low and behold matches the original speck in the manual . I found an original data sheet on  the steppers on the machine. They are only 430 oz-in motors not 1280 like the later version. I guess you really don't want super fast rapids on a training lathe anyway . They really are marginal and have trouble compressing the counterbalance spring on the cross slide without missing steps. Its sad, but the little nema23 stepper I put in the turret would run circles around the axis motors . So off to eBay with them and the drives. I have a PacSci K33 that's been wanting to make itself useful for 5 years or so. I'll have to wire it bipolar-series to keep from frying the gecko drives, but it should be more than adequate. I'll put it on the cross slide. I ordered an 1800 oz in motor from Keling to put on the carriage, and I'll up the voltage to 50V. If that isn't good enough, I'll order a new power board and go up to 80V, but I don't think that will be necessary. I'm going to use gecko 203Vs.

On a positive note. I got the turret powered up and moving around. I had a terrible time with the encoder on the turret shaft. The position strobe has a 1deg window. Something that lends itself to bench adjustment, rather than on the machine. I took all day Sunday to get it adjusted. Tightening the set screw would disturb it, then finding it witout a scope was a real pain because of the time delay on the meter . All of the proximity switches and other stuff on the turret work fine. Programming is going to be a challenge for me.........Fortran, COBOL and basic are the last programming experience I had a loooooooong time ago. AHH well another adventure.

 

That sounds a lot of speed for a 7.5Hp  servo, also better watch you dont crash the turret into the spindle or you will do some serious damage with that much pwer LOL
 Would imagine the bearings could stand much more than the 2500 but dont go too high as your chuck may be a limiting factor, what size is the chuck and is it iron or steel?
Hood

Hood,

The chuck that came with the machine is a nice 6 in Maier forged steel unit. The pulleys are about a 2:1 ratio so I would be able to get about 4000 spindle rpm. I did find that EMCO made a 240 which looks exactly like the 140 except it has a powered tailstock and the machine is totally enclosed. It appears to have the same spindle as mine and was rated at 4000 rpm. Most likely the only time I would use more than 2500 rpm would be with small parts and a collet.

There is a reason I put a 1/2 in polycarbonate sheet in the door window, but I hope it is never needed .

Monty

You should be fine, most steel chucks of 6 in dia are rated about 4500RPM.
Hood

Sometimes I question my sanity.

This past Saturday I got up at 0500 made breakfast for the BOSS. Slammed my coffee, grabbed the chocolate covered espresso beans and departed north into the freezing mist. 7 hrs, many frozen salted icy miles, and one fill up later I arrived in East Alton IL; a thoroughly depressing place, at least this time of year . I then loaded up my prize and headed back South. About 1500 hrs I finally got a chance to drain the morning's coffee and get a bite to eat. Then back on the road. Hurtling along at 80+ mph listening to anything to keep me awake, I suffer through a Christian demonic possesion program , and some song about driving a tractor that hasn't left my head two days hence . Finally I get back into the mountains well after dark and the folk sampler is on....bluegrass....much better than the contemporary stuff AHHHHHH.

Somehow I survived.

This afternoon after my work was done for the day I decided to pull the original spindle motor. Then the scary thing happened. The new motor fit the machine, no adaptor plate, no bushing for the spindle pulley, Same length shaft the whole bit. Looks like it grew there. The new spindle motor is brand spanking new, still had the connector and crimp terminals for the encoder in a little plastic baggie in the terminal box. I am quite terrified, as nothing EVER goes this smooth. Something must be wrong. It did have a little shelf rash, and I had to dust it off. Other than that it worked out better than I could have hoped for.

The Spindle drive needs an add on card to do positioning, that will have to wait.

Next I have to modify the axis motor brackets and mount the new motors. Then rewire the control cabinet.

Right now freezing rain is coming down at a pretty good clip outside. The forcast calls for around 1 inch of ice. Somebody needs to phone Al Gore and tell him to turn up the thermostat!

I hope I have power in the morning. The oil lamps are filled up and there is a good pile of wood by the stove, so I'll survive as long as the cognac lasts....

I'd rather be lucky than good any day .

Monty

Paid for my luck with the spindle drive with 1.5 inches of ice and no power for 10 days. Stranded at home for 4 because the driveway was blocked with downed trees and power lines.

The dog is worried he is going to run out of food .

I tried to save this tree when we cleared some land. It was about 20 inches in diameter and straight as an arrow. Peeled like a banana.

What a mess. I'll be cleaning up for months.

Monty