# Variable Speed on Lathe



## Rich Aldrich (Apr 26, 2008)

I am considering a lathe and of course going through the whole gamet of research. I started thinking....

One of the issues with the Griz and ShopFox lathes is that the low end speed is not low enough. Even on the Nova 1624-44, variable speed would be nice. 

At the paper mill where I work, we are installing a lot of ABB variable speed drives on equipment. These are 3 phase, 460V. I asked one of our electrical engineers if ABB makes a single phase variable speed 110V. He checked into it. ABB makes single phase, 220V in 1 HP, 2 HP and 3 HP. The price for a 2 HP is about $170 and a reostat for about $12. If you had a tach on the lathe, you could get a digital controller instead of a reostat. I think, no guarrantees, one of these drives would work on a lathe as long as the motor can be rewired for 220V.

This could also be installed on a Jet 1442, I believe.

Ideally, the motor should be rated for variable speed, but we have not had much trouble with motors with variable speed drives. Most of ours are not rated for variable speed drives.

The drive has the capability of spinning backwards and can run the motor a bit overspeed.

Any thoughts?


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## woodnthings (Jan 24, 2009)

*Rich I remember when Sears tried VS*

They seemed to have a problem overheating at continuous slow speeds since the fan wasn't drawing enough air overthe windings.
An auxiliary fan might do it.....or water cooled!:no: Just a thought from the past! :blink: bill


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## Rich Aldrich (Apr 26, 2008)

On these lathes, you still have the belt drive so you can keep the motor speed up by shifting the belt to a lower speed.

We have a lot of old motors in the mill that we do not have a problem with overheating. The rating of the motor may be an issue here because not being continuous duty or TEFC (totally enclosed fan cooled).

The auxilary fan may be a good way to take care of overheating. We have a couple of applications where there is an auxilary fan to keep the motor cool.

I would be suprised if it is a problem. In most cases, I dont think you will run the motor slow for that long for it to become an issue. This is from an inexperienced turner.


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## Kudzu (Dec 23, 2008)

VFD's (variable freqency drives) are becoming more and more affordable and common in the home shop. Your can find them powered by 220v up to I think 2.5 hp? I have one set up on my lathe and it's the ultimate set up for speed control. But the motor has to be a 3 phase motor, not a single phase 110v. Unless there is something new out there is practical way to vary the speed on a single phase motor. That is why I searched out a old-iron 3 phase lathe.

Overheating can be a problem. But on my old iron lathe it has a variable speed reeves drive to start with. So I run the reeves drive all the way down and then use the VFD to lower my speed further. That keeps the motor speeds up as high as possible. 

If your roughing a big blank at low speeds you putting a pretty good load on the motor. More so (at least I think) than at high speeds when you trimming. I have never stalled mine at high speeds except with a catch. I have stalled it a lot roughing blanks.


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## Rich Aldrich (Apr 26, 2008)

Kudzu,

I was reading the specs on the drive and you are right that the motor has to be three phase, so you would have to replace the motor. The frame would probably different and cause other issues that would probably not make it worth the hassle.

Back to researching and deciding which "standard" lathe to buy.


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## Barry Ward (Mar 22, 2008)

*Variable Speed on a lathe*

Hi I have the Nova 1624-44 and wouldn't want to run it any slower than the 216 (I think) RPMs as it does bog down the motor.I have used the VS an they are nice.A lot of folks think you should run lathes real slow when you have a big blank on em,but I have found that the biggest mistake is not making the blank as round as possable before turning it.I start 16" blanks at around 400 rpms on the Nova with no problem,then as soon as they are true I go up to the next speed.


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## hughie (Mar 22, 2008)

I had a Chinese MC1100 that had a reeves type vari speed, fairly hopeless and real tough on belts due to poor casting of the pulley set up. etc
I fitted a three phase motor to it. Input single phase out put three phase. To this, I also fitted a small 10x pot or rheostat as you say, and to get around the low airfolw problem I fitted a three step pulley system as well. This also keep my torque ratings where I want them as well. Its not a difficult process but most defintely worth while.

If you dont want to fit a pulley system then remove the rear cowl and fan replace it with a single phase cabinet fan ie like a large PC cooling fan. Wire it up via your control switch this will give a steady flow of air no matter the speed of the motor. It will work very well and I have done this several times on other applications.


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## john lucas (Sep 18, 2007)

I replaced the motor on my Nova 3000 with a 3 phase motor and Variable Frequency Drive. It was the best thing I did. You can buy these at www.dealerselectric.com Most of the new lathes have these drives. They come in 110 and 220 single phase in versions. You do need to make sure the VFD and motor match.


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## Barry Ward (Mar 22, 2008)

*Variable speed on lathe*

John ,I have considered putting VS on my Nova 1624.I went to that site,but don't quite understand the cost.Do you have to buy the motor,switch,converter all seperate.I was just thinking about upgrading to a 3hp 220.I love the 1624 as is,but was just wondering on the cost.


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## john lucas (Sep 18, 2007)

You'll have to a call them to get price quotes. It's been about 5 years since I did that. I believe they have package deals. On mine, I put a master on off that sends power to the unit. This was a seperate switch. Then I made a remote switch that had a speed control and on/off and reversing. The VFD has outputs for these controls, at least mine did.


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## Barry Ward (Mar 22, 2008)

*Variable speed on a lathe*

Thanks John,I apreciate that


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## Rich Aldrich (Apr 26, 2008)

*VFD with Single Phase Output*

I found a VFD that will output single phase. I am not too sure about it though, there are issues with single phase output.

http://www.invertek.co.uk/product_optidrive_e21.aspx

DC is another output option that I havent considered.


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## john lucas (Sep 18, 2007)

DC is much easier to hook up but it has very low torque at low speeds. The VFD is more difficult to wire up but has a lot more power at the slow speeds. It also has electronic braking which is really nice if you turn larger work.


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## Bob Willing (Jul 4, 2008)

*Woodcraft*

Check out Woodcraft they have a Jet on sale! http://www.woodcraft.com/product.aspx?ProductID=147823&FamilyID=20138


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