Need help hacking my lathe!

Bill Lantry

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OK, Folks,

I'm back on it. I've gotten pretty far with figuring out this project, but I'm stymied at this point. I thought I had it all figured out last night, but the harsh light of day shattered everything.

Here's the lathe I'm hacking:

g0462.jpg




Nice, solidly built frame, halfway decent bearings in the spindle, reeves drive. We all know the problem: lowest speed is too fast. Only solution: VFD and a new, 3 phase motor. I'd like to stay at 2 HP, since most of the better lathes are 1.5 to 2 HP. Based on the VFDs I've found, that pretty much means I need to run 220 into the shop, which I guess I should do anyway. The 110 VFDs pretty much top out at 1 HP. So...

220 to the shop (it's really only a 20 foot run from the main panel in the basement, and I've already got a now unused 220 breaker on the main that used to power the oven). Subpanel in the shop, with both 110 and 220 coming out of it. Here's the VFD I'm thinking will do the job:

http://www.factorymation.com/s.nl/it.A/id.196/.f?category=32

single phase in, 3 phase out. I'm not real clear on how to hook it up, but I can probably figure it out. I figure I can route around the switch on the lathe. Not real clear on how to set speed controls on it, but again, I can probably figure that out. It's $145, so that's inside the budget.

OK, on to the motor. I want to keep the reeves drive... and doing that uncomplicates part of the project. That means I only need to worry about the motor spindle size, which I take it is not universal or standardized. But I can measure the shaft on the existing motor. The real problem:

As far as I can tell, I need a motor that is

3 phase
2 hp
tefc
inverter duty
c-face
about 1700 rpm

and probably a bunch of other variables that I have no idea about. I found this motor last night:

http://www.surpluscenter.com/item.asp?UID=2007092711250329&item=10-1810-A&catname=electric

for 70 bucks, and got very excited. That's a price within reach. it's not tefc. It's not inverter duty (whatever that actually means). And I don't know the spindle would match. So, I go searching for a motor that I think might match my percieved specs, and can't find anything for less than many hundreds of dollars. Am I barking up the wrong tree? How does one go about finding a motor like that for under a hundred bucks? This all started because people said I could pick up a 3 phase motor cheap. HELP! ;)

Thanks,

Bill
 
okay bill......givens are;
1)"c"face
2)reeves id..= shaft od

darn near any 3 phase motor can be frequency controlled but if loaded at 1/2 speed they can get hot......hence the recomendation for a motor rated for inverter use.....where it me and i found a motor of suitable mounting (see #`s1&2) i`d get it whether or not it was rated for inverter use, and try to keep it close to it`s rated rpm`s.......i don`t think that by putzing around an hour here and an hour there at lower rpm`s that you`ll severely shorten it`s usable life?
but know that i ain`t no `lectrition!

even if you`re able to toast a motor in a couple of years.....and that`s questionable...... it`s pretty likely that you`ll be ready or at least wanting to upgrade;).....
some thing to think about.... tod
 
Funny Stu, I was just reading this thinking I needed to reply. :)

I have done something very similar with and Old 3 phase lathe. The VFD with Reeves works well. No problems there.

As for you motor I would simply call the Surplus center and ask for more info. I believe there are standards on c face motor mounts. You just have to determine what you need vs. what they are selling to see if it will fit. If it will fit your half way home. Check the shaft dia. and length too!

Wiring a VFD is fairly straight forward. But the manuals are written for Electricians and even though I am very comfortable with this type of stuff, I had to read it a few times to understand it. If you wire one up backward it sounds like shotgun going off when you give it power. DAMHIK. :eek: BTW, if you shop you can probably find one cheap on EBay. Just takes some patience.

VFD's do not like two things (well three if you count backwards wiring). Vibration and dust! See where I am going yet? You really don't want to mount it on the late. I suggest you mount it on the wall, run power cord from it to the lathe. With most VFD's you can hook up remote control. Forward, reverse, speed and on and off switches. You just use very small cable, CAT5 should work. Mount some off the shelf toggle switches and a POT for speed control in a box and attach it to the lathe with a big magnet. Keeps the controls close and VFD out of the dust and vibration.

How do you turn your lathe on? Is it on the speed control switch? If so then you will need to tie that switch into the VFD. I did that one mine and it's slick!! Works like factory and I use the speed lever most of the time. When I need slower speed I set it on low and then adjust the VFD. Most times I leave it (VFD) on full speed.

That help or confuse?
 
This is just a guess, but I suspect the reason some 3 phase motors get hot at low speeds is that they're designed for a certain air flow, which is provided by the internal fan when operating at rated speed.

I'd just get a fan and blow it on the motor to help keep it cool. And I'd also take Tod's approach and start with a low cost motor, even if you toast it in a few years. You'll get the experience and will know more about what you want after using it for a while.

Mike
 
Hey, folks,

Thanks for your responses so far. I really like the idea of going with a cheap motor. After all, this is really just an incremental step... someday, a few years from now, I hope to have a *real* lathe... ;) If I burn out two motors over the next three years, the cost is not that much by comparison to a oneway... ;)

So are you saying I don't need to worry about the TEFC part, or the inverter status? In other words, is it worth a try to just go with the $70 motor I referenced above, even if it means that this time next year I'll have to pick up another? Seems like a decent trade off to me...

More later,

Thanks,

Bill
 
if ya` got an air hose and 20 min a year the odp motor will work for a few to several hundred hours....blow it out when you`re done and clean it well once a year. 3-phase motors don`t have centrifugal switches and mechanical stuff to clog up like single phase units do, windings-n-bearings......
 
Oh, one thing I have is an air hose! ;)

But did you mean

"odp motor will work for a few to several hundred hours"

A few hundred to several hundred hours?

Or

a few hours to several hundred hours?

If it's the first, I'm in business! ;)

Thanks,

Bill
 
Jeff,

I'm intrigued by this paragraph:

VFD's do not like two things (well three if you count backwards wiring). Vibration and dust! See where I am going yet? You really don't want to mount it on the late. I suggest you mount it on the wall, run power cord from it to the lathe. With most VFD's you can hook up remote control. Forward, reverse, speed and on and off switches. You just use very small cable, CAT5 should work. Mount some off the shelf toggle switches and a POT for speed control in a box and attach it to the lathe with a big magnet. Keeps the controls close and VFD out of the dust and vibration.

First, the mounting: Yes, I could mount it to the wall. But here's a picture of my existing lathe stand:

attachment.php


I was thinking of putting the VFD either under the benchtop, directly beneath where the lathe headstock is now, or off to the left side, attached to the front left of the lathe stand. I figured the wood would dampen the vibration, but maybe not enough.

On the other hand, if there's one thing I've got plenty of it's cat 5. But what would the interface device be, where would I get one, and how would I hook it up to the VFD? Got any pics? Or places where I can start researching?

Thanks,

Bill
 
Oh, one thing I have is an air hose! ;)

But did you mean

"odp motor will work for a few to several hundred hours"

A few hundred to several hundred hours?

Or

a few hours to several hundred hours?

If it's the first, I'm in business! ;)

Thanks,

Bill

i meant the first bill:eek:
 
I was thinking of putting the VFD either under the benchtop, directly beneath where the lathe headstock is now, or off to the left side, attached to the front left of the lathe stand. I figured the wood would dampen the vibration, but maybe not enough.


Well, it is up to you where you mount it. Are you willing to take a chance with $150? :dunno: But you still have to deal with the dust. Unless you put it inside the cabinet it's going to be exposed to a fair amount of dust. My thinking is you have to run a cord from an outlet anyway. So just mount the thing on the wall and run a cord from it to the tool.

I have seen several people mount them on metal bases on machines. I don't know if anyone had a failure or not. I just know the manufactures say to avoid the vibration and dust.

On the other hand, if there's one thing I've got plenty of it's cat 5. But what would the interface device be, where would I get one, and how would I hook it up to the VFD? Got any pics? Or places where I can start researching?

No photos handy but your just connecting from the VFD terminal strip to standard off the shelf toggle switches for ON-OFF, A two pole toggle for FORWARD-REVERSE. Then a potentiometer (pot) for the speed control. This one will be specified in the instructions. All standard off the shelf Radio Shack items.

Then you just mount them in what ever enclosure you like. Again Radio Shack stuff or electrical boxes.
 
I used the exact same VFD for a lathe I rebuilt and later sold. I think I have an extra multi-turn pot which you are welcome to. You don't want the one from Radio Shack as it is less than a full turn and is way too sensitive. The multi-turn is much less sensitive and easier to adjust.

For the controls, I bought a switch for Forward-Off-Reverse and a mushroom head pushbutton for and Emergency Stop, and the legend plates for both from FactoryMation. If you do that you need the actuators (the actual knob and button) and the contacts which are sold separately. I mounted all three controls in a small box I bought at Radio Shack and it turned out nice and professional looking.

My lathe was one of the old Delta's with a cabinet so I put the VFD in there. I'd recommend putting it inside some kind of enclosure because the terminals are exposed. There are finger-safe, meaning you can't accidentally come in contact with just a finger, but still. Also, the top is open for ventilation and I'd want something to keep the worst of the chips out. In an industrial setting these are typically mounted inside a panel.

Wiring and programming was pretty straight forward.
 
Bill,
It's a very doable project, just jump in and go for it, you'll be happy you did when it's done. I repowered my 1950 Delta model 1460 lathe with a 2hp 3ph and VFD and my 1951 Walker Turner 900 DP with a 3/4 hp 3ph, the only regret I have is I didn't do it sooner! Don't get too wrapped around the axles about the inverter duty and TEFC or ODP designations. Keep in mind these are industrial rated motors. They're designed to run for months and years on end. The average hobbyist will never work them anything like that. If you're like me then the lathe might run for 4 or 5 hours at a time max. Yes you need to worry about over heating them, but they take a lot more punishment than you'd imagine.

More hp is better, HP is a rating based on the RPM of the motor. For simplicity sake think of it like this; if your motor produces 2 hp at 3600rpm then it will only produce 1 hp at 1800rpm and only 1/2 hp at 900rpm. with that in mind you want to try and keep the rpms up with pulley ratio or in your case the reeves drive. Use the VFD to fine tune your speed. You want to keep the rpms up also to keep enough air moving through the motor to keep it cool. With that said, my motor is a 1971 Marathon 2ph 3ph 1800rpm ODP motor which I paid $20 for NOS! I've run mine at 400-500rpm (motor speed) for several hours straight and it only got warm. I blow it out after each heavy turning session and have no problems. Would a inverter duty, TEFC motor be ideal? Sure, but don't sweat it if it's not...

All my tools have to be mobile so I had to mount the VFD on the lathe. Not perfect, but it works fine. I build a box with a fan, filtration and vibration isolation which you can see mounted under the lathe. It's probably overkill but I made me feel better. You could do something like that with yours under the bench and run your controls up through. I've talked to several knowledgeable folks since I did the lathe. While VFDs are sensitive to vibrations, they will tolerate some. The warnings are about massive vibrations you might find in a industrial setting, not what you and I would subject them to with normal hobby use and care. (I'm sure I'll endure the wrath of all the self proclaimed experts for that little comment:D)

The wiring is not that difficult, pretty simple actually. for the 220v models you attach L1 & L2 to the posts labeled, get this, L1 & L2! Who'd a thunk it;). Next you attach the 3 wires for your 3 ph motor, T1, T2 & T3. You can't screw this up, it doesn't matter which wires you attach to which post... the only issue you will run into is it might run backward. You can fix it by switching any 2 wires or use the VFD settings to switch the direction. Your motor will run at this point, put power to the VFD and hit the run button! You'll probably want to wire a remote start/stop station though. You have several options at this point. You can buy a off the shelf solution (expensive) or build your own. I used a 6"X6"X4" box for my lathe and mounted it on a stalk. I just did my Walker Turner 900 DP also and used a box I found at HD which I modified a bit. Use your imagination.

The VFD needs to have it's own power switch to provide power to it. You'll use either the keypad or your remote buttons to turn the motor on/off. I'd imagine you'll want a remote as sticking your head under the cabinet to turn it on and off will get old quick:D The remote control switches are low voltage so you can get away with using cheap toggle switches from Radio Shack. I prefer to used industrial quality switches though, their fairly cheap ($5-$8 each average) and look a LOT more professional IMO. As you can see I've got a switch to power up the VFD. The idiot light is also wired to the main power switch so I don't forget to shut it off. The motor is controled with the Forward/OFF/Reverse switch. On the DP the VFD is powered up with the main power switch and the motor is started with the original "on/off" switch on the DP.

Mike

Here's a few pix of my setups:
lathe1.jpglathe2.jpglathe3.jpglathe4.jpgdp.jpg
 
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One thing I forgot is that you probably want a 2 pole switch on L1 and L2 to kill power to the VFD completely. I just put a disconnect swith on the wall before the outlet I had mine plugged into. I read somewhere that the inexpensive ones are more sensitive to surges--killing the power prevents them from getting through when you aren't using it.
 
OK, folks,

So I spent a fair amount of time taking the lathe apart last night, and grabbed some pictures as well. Like I said, I never know how something actually works until I take it apart... ;) This first one shows the mechanism that determines how the headstock swivels on the base, so it's not immediately relevant to the task, but still interesting:
.


lathe 001 (Medium).jpg
.
In this one, I've got the motor off the housing. Giant hassle, but done...
.




lathe 003 (Medium).jpg

Here's the housing. You'll notice the sleeve makes a three quarter circle, which is why it's such a hassle to take the thing apart. Geez...



lathe 004 (Medium).jpg

Here's a closeup of the motor with the reeves drive still on. I now know exactly how a reeves drive works, when two months ago I didn't even know what one was... ;)

.
Housing has 4 bolt holes, spaced at 3 1/4. I'm hoping that's standard????



lathe 005 (Medium).jpg

.


lathe 006 (Medium).jpg

.

I'm hoping this isn't a project killer. The shaft comes out 4 1/4" from the motor, and the reeves drive needs every inch of that. Dang!


lathe 007 (Medium).jpg

lathe 008 (Medium).jpg
.
These next two are really bad pictures. If you could read the tape, you'd see that the shaft is 5/8" in diameter..

lathe 009 (Medium).jpg

lathe 010 (Medium).jpg
 

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The reeves drive is held on with a clip. I clearly need one of this specialized pliers-looking-things-with-little-posts for installing and disinstalling metal clips. No idea where to get one, or what they're called, so you can see how hopeless I am.

lathe 011 (Medium).jpg
.


lathe 012 (Medium).jpg

Anyway, to make a long story short:

I did get the thing apart last night. I don't know if the motor housing is standard. The biggest worry is the size of the motor shaft. Assuming I can fit another motor into the housing, the shaft will need to be 5/8" in diameter, and extend at least 4 1/4" from the motor.

I need help on this one. Are shafts interchangeable? I've never heard of people worrying about this, so maybe it's not a major issue? I have no idea. It seems odd that the motor specs I've found seldom list the numbers for the shafts? Can I use this shaft in another motor? Am I biting off way more than I can chew?

HELP!!! ;)

Thanks,

Bill
 
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One thing I forgot is that you probably want a 2 pole switch on L1 and L2 to kill power to the VFD completely. .........

Good point, I didn't think of that. I simply put a short pigtail on my VFD and a plug. That way I can just unplug it from the outlet. That way if there is a lightning induced surge it won't just arc around the switch.
 
go to a power transmission web site and see what style reeves drive sheaves they have available? if you`re lucky you`ll find one that`ll fit the shaft of an off the shelf motor...only problem then is mounting it on a bracket that`ll bring it inline with the other sheave.....if you`re unable to find a direct bolt in it`s probably not worth the trouble reengineering the lathe...
 
Just keep looking, the one thing I have learned (or had to learn) is to be patient. What ever it is I am looking for comes along sooner or latter. Your lathe will still be there. ;)

And keep check the surplus sites as they get stuff in all the time. EBay is another good place for cheap 3 phase motors.
 
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