It's alive, Franken Lathe is alive! (gloat:)

[Bill Lantry]

Bob,

I keep coming back to this one:

http://www.factorymation.com/s.nl/it.A/id.193/.f

But on a certain auction site, there are warning that say "do not use static converters with a lathe" I'm so ignorant of this stuff I can't even tell if that means me...

Thanks,

Bill

[Jim Becker]

Bill...rest easy...a VFD is not a "static converter".

[Bob Hallowell]

Bill,
it is that one in a 2hp version but like Jim said it is not a static convertor. Vfd's are what all the big boys like your powermatic, stubby, robust, and oneway's use.

Bob

[Bill Lantry]

so, OK, 2hp. And then a motor like this one? http://www.surpluscenter.com/item.as...tname=electric
Yes, no, maybe so?

I'd rather buy new, just because I have a better chance of actually getting it to work!

And this will get me speed control from, say, 0-1500 (I rarely go much faster than that) and enough torque in the low end to spin a large blank? The lathe itself has a 16" swing over the bed, but since the low end speed is so high (supposedly 600, but I suspect it's faster than that) that I've never even tried something that big. Right now, even a 12" unbalanced blank is pretty scary...

This is getting exciting!

Thanks,

Bill

[Bob Hallowell]

Bill,
Yes, no, no

Yes you need a 3phase, 1-2hp motor depending on ho much power you want. but that motor has several flaw.

1st- it should be an inverter duty motor- Mine is not It was cheap enough I am trying to get away with it.

2nd- it should probally be a tefc (totaly enclosed fan cooled) instead of an open drip proof

3rd- 3450 rpm's would be hard to slow down, I think you would want 1720 rpms instead. It would be easier to belt to a speed of say 800 rmp

4th- I don't think you would want a c-face motor they are harder to mount.

I think you want to be looking at something like this http://www.surpluscenter.com/item.as...tname=electric

Bob

[Bill Lantry]

Bob,

TEFC makes perfect sense to me. By "Inverter duty" do you mean reversible? If not, I don't understand

1800 would be *plenty* of RPMs for me... great suggestion.

on the c-face: you may be right, but don't forget this is what my headstock looks like now:
I really don't want to lose the functionality of being able to pivot the headstock so I can do outboard turning... I built a giant bench for the lathe *just* so I could do that. I don't see how I could get a base mount to do what I need?

Here's a better picture of the whole thing: shows how the motor's mounted:





I'd also like to keep the tachometer, but that's a minor point...

Thanks,

Bill

[Bob Hallowell]

Ahh!

Then Bill you do want a cface my bad.

Inerter Duty Motors are designed for optimized performance to run with variable frequency drive. The Inverter Duty Motors have independent cooling fan to cool down motor. It can operate for wide speed range without any heating problem.
A standard motor driven by the inverter generates slightly less power than it does. When it is driven with commercial power supply, also, the cooling effect deteriorates in low speed range, then the motor temperature rising increases.
Reduce load torque in the low speed range. Allowable load characteristics of the standard motors are shown in the figure. If 100% continuous torque is required in the low speed range, use an inverter duty motor is reliable.

I think that said it better than I could of. Like I said before though I did not use an inverter type motor but they are recomended..

If you are planing to keep your reeves drive on you might want to make sure the shaft is the right diameter.

Bob

[M Toupin]

Bill,
If it was me I'd opt to keep the reeves drive intact and use it to select a rough speed range then use the VFD to control your speed from there. You want to try and keep your motor turning in the top half of the speed range or so to keep the torque up and more importantly to keep enough air moving though it to keep it reasonably cool. Not that you can't run it real slow for a short time to say round out a rough blank, but I wouldn't do it for hours at a time. The 3450 motor would work, but I think you'll be happier with a 1800 (or so) rpm motor. Your torque is Dependant on the RPM so the slower you run it the less power you'll have, just a few things to think about.

Here's a old post by Don Baer that is an excellent primer on VFDs, 3phase motors, torque and horsepower which should help explain a lot.

http://www.sawmillcreek.org/showthread.php?t=39536

Mike

[Dick Strauss]

With a better inverter duty motor (like Baldor), you get constant torque over a 1000:1 ratio. That means you get constant torque down to 1.75 rpms on a 1750 rpm unit. In addition, a 1750rpm 1hp motor has twice the torque of a 3500rpm 1hp motor (HP = (T x RPM)/5250 ).

Inverter duty motors also use better insulation for the motor windings to prevent them from creating shorting discharges within the motor housing.

3 phase does mean the motor is designed to be reversed.

[Allen Neighbors]

Congratulations to Frankie for finally coming alive!! and to Bob, for making it happen!
Pics of turnings are now in order.

[Bill Lantry]

OK, for some reason I was thinking the reeves drive would be replaced. So then I thought 'well, maybe I could just keep the reeves drive intact, and put a new motor on it.' So I thought I should open it up and see what it actually looks like inside (check the spindle size, mounts, etc. to see what would work)

But looking at the parts diagram (http://images.grizzly.com/grizzlycom...s/g0462_pl.pdf) I'm wondering if I even need to do that? I mean, if they make a VFD with a single phase output, couldn't I just plug or splice the power cord into that? Wouldn't that get me what I needed? Or do such animals even exist?

Thanks,

Bill