Going To Buy A Lathe... Thoughts, Input Solicited By Inexperienced Dufus

Tony Wells said:
VFD basically is a variable speed electrical control with programmable accel/decel profiles, and reversing. IMO, with that machine you don't need the reverse. That motor will run (in its original configuration) in one direction, with reversing of the spindle coming from the gearbox. As far as the accel/decel that's a nicety, but hardly a necessity. A VFD can be set up with a brake, but their main claim to fame in the hobby world is the ability to run 3 phase equipment on single phase. HOWEVER, the size VFD for a 15 hp motor will be pretty healthy, and priced to match. You said you did not have native 3 phase, correct? Another issue you will need to address is the current draw for a motor that size. Even with 230/240 available, how much current? You're probably looking at ~40 amps continuous on that motor. It's on the plate if the plate is still there. That's another major factor in sizing a VFD. We have some here who are very well versed on VGD applications.

I personally am not a huge proponent of VFD's, but some people are. I have been around them and used them on a few things, up to 250 hp, so I do have some experience with them. On machine tools, I must have some bit of purist in my heart.....I like to see them as designed, for the most part.
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Tony,
My plan had been to buy a rotary phase converter large enough to handle this lathe, knowing anything else I'll have that's 3 phase will have a lower power requirement. The RPC I've been looking at should give me what I need, but requires a sixty amp breaker in my panel. I'll have to buy one. Plenty of room for it, both in terms of physical space and total amperage. You're right on the amperage, or close enough. The motor currently on the lathe is right at 39 amps, and the replacements I've looked at are all within 1amp of that either way. It's just what it takes to run a 15HP motor, so no surprises there. Looking around as I've had a spare moment or two, I notice there are other limitations on a VFD. I'm really thinking my best option will be the RPC sized for my needs. Wire up a circuit for it, let me power whichever machine I need at the time, and go on with it. Of course, I'm always open to other arguments.

Thanks again!

Mark
 
4gsr said:
Crap!
I didn't realized all of the electrics were removed from the machine. Will have to watch for a Hoffman enclosure about 24" square by at least 9" deep, 12" would be ideal, 6" might work, but of you came back later and wanted to install a VFD, wouldn't be enough room for it! I'm on the road today heading back to Victoria. Give me a holler in the morning. I may still be wiped out from my trip, just depends on how traffic is, going down IH35 today. Ken
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Ken,

Looks like I'll be heading to Victoria in the morning... Going to try to get out of here at 630 just so I've turned South before the sun comes up. I drive East to Cameron, and directly South down 77.

So yeah, I want to be South bound before that big yellow orb makes driving suck. I'll holler at you when I get to Gene's. Then I'll get loaded. That way if you're up to it, and aren't too done-in from today's drive, we can have brunch/lunch or something.

Thanks!

Mark
 
markamerica said:
Ken,

Looks like I'll be heading to Victoria in the morning... Going to try to get out of here at 630 just so I've turned South before the sun comes up. I drive East to Cameron, and directly South down 77.

So yeah, I want to be South bound before that big yellow orb makes driving suck. I'll holler at you when I get to Gene's. Then I'll get loaded. That way if you're up to it, and aren't too done-in from today's drive, we can have brunch/lunch or something.

Thanks!

Mark
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Yeah,
Watch out for the cop in Lexington, cost me $$$ back in May. Ouch!!!
Call me when you get here, if I can break loose, I'll come meet you at Gene's Machine.
I've have a full plate of stuff I got to get done in the next day or so.
Ken
 
Hi Mark
The lathe is reversed in the gear box. The motor runs one direction all the time. There should be 3 arms with handles along the length of the lathe for forward and reverse and braking. Sorry I have been busy, I forgot to get you the size. The electrical box is 26" wide x 14" high x 8-1/2" deep. My guess was way off. :drunk:
I run mine on a 10 hp rotary Phase converter and a 600 volt step up transformer. It should really be a 15 hp phase converter but I had this one and it is working just fine
Cheers
Martin
 
4gsr said:
Yeah,
Watch out for the cop in Lexington, cost me $$$ back in May. Ouch!!!
Call me when you get here, if I can break loose, I'll come meet you at Gene's Machine.
I've have a full plate of stuff I got to get done in the next day or so.
Ken
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Ken, I had to wrestle with a trailer light issue since my last post. Now I get to check all the tire pressures. Joy. Better now than down the road. I'll watch for the guy in Lexington. Hauling the trailer, I probably won't run afoul anyway. I'll holler at you when I get there.

Thanks!

Mark
 
Martin W said:
Hi Mark
The lathe is reversed in the gear box. The motor runs one direction all the time. There should be 3 arms with handles along the length of the lathe for forward and reverse and braking. Sorry I have been busy, I forgot to get you the size. The electrical box is 26" wide x 14" high x 8-1/2" deep. My guess was way off. :drunk:
I run mine on a 10 hp rotary Phase converter and a 600 volt step up transformer. It should really be a 15 hp phase converter but I had this one and it is working just fine
Cheers
Martin
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Martin, no harm no foul. It looks like impending bad weather has forced me into an earlier run to get the beast than I thought. I'll look for a box around those numbers, as I'm going to have to build from scratch. Ken's been kind enough to volunteer to help me get it built right. I'll be doing the rotary phase converter too, unless somebody can convince me of a better idea. All reports I read on them suggest better reliability.... But maybe that's hype too. I guess we'll see. I kind of like the nifty neat arrangement shown in that one updated box on page three of this thread. That's nifty.I think I'll shoot for something kinda sorta like that.

Thanks again!

Mark
 
Met with Mark for a few minutes this morning. He has a decent looking lathe there. Will need some work to get it running again. That old lathe is heavier than it looks! He has a load on his hands! Hopefully he has a safe trip back home! Ken
 
4gsr said:
Met with Mark for a few minutes this morning. He has a decent looking lathe there. Will need some work to get it running again. That old lathe is heavier than it looks! He has a load on his hands! Hopefully he has a safe trip back home! Ken
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Ken is an awesome guy! Lathe on trailer in barn. Home in 1 piece. New info revealed on lathe, more on all of that later. Right now, shower and grub.

Thanks!

Mark
 
12bolts said:
Mark, the gauge on top is most likely a tachometer

Cheers Phil
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Phil, that's what it is: Spindle RPM. I know the one I bought once had one based on the mount holes on the lid.

More about this and other stuff later.

Thanks!
 
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