Converting lathe to 3 phase

C

cdement405

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I did a search and didn't come up with much. I was wondering if anybody has converted there single phase lathe to 3 phase? Do I just have to change the motor to a 3 phase motor and connect it to a VFD? I have just about made up my mind on a 4003G grizzly lathe but would like to slow it down below what the lathe will currently run. Will converting it to 3 phase solve this problem? Any help or advise with this would be greatly appreciated.

Thanks
 
Converting to three phase..

I converted my Grizzly Precision Tool Room lathe.

My lathe came with a 3 hp single phase motor.

The three phase motor with the same footprint and shaft size had 5 1/2 hp.

Grizzly lathes are metric and you can buy a metric motor, that way you can use your same sheeves.

I used a Westinghouse FM 215 VFD.

It uses single phase 220 input and converts to true three phase.

Don't be freeked out when you find out the three phase motor has 16 wires they are paire in banks of 4. Just read the instructions to get the colors right.

Nat Lambeth
 
Butch,
I clicked on the link you provided but it took me to a page that didn't have any information on the page. Thanks for the help though.
 
That is strange. I did a search on phase converters and that page came up with several threads. I think you need to try the search again.
Butch
 
Thanks Butch

I appreciate the help I got the search working for me and found several helpful threads.

Thanks Again
 
A cousin bought a phase converter from Graingers about five years ago and did his. Their 3 hp is $223, 4 - 8 hp is $324.

OOOPs, I see your wanting to go from single to three, he went from three to single.
 
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I bought a Jet heavy 13x40 single phase lathe late in 2005, and started having motor problems a little under a year later. After a couple of months fiddling with new starter contact points & etc., I scrapped the chicom POS and replaced it with a US Motors 3hp 3-phase, powered by a Westinghouse/TECO FM 215 VFD, which as Nat stated, converts single phase into true 3-phase, and is rated at a full 3hp, so the motor can develop its full rated power. The results were very pleasing, so when I purchased another lathe, I got the 3-phase version, and bought another VFD (went with a Hitachi SJ200, as the FM215s are no longer available).

Not only do the 3-phase motors run smoother, but I have both VFDs programmed for a 'soft start', which ramps motor speed up smoothly over a 2sec. time frame instead of just snapping into full RPM more or less instantly - this has got to be easier on the gearboxes. I've also programmed them both to coast to a stop, as I didn't order the optional braking resistors needed to keep the standard resistor from overheating when the unit is programmed to brake the lathe to a stop.

After my experiences with these two VFDs, I believe I'd use VFDs to control the machines even if I had 3-phase into my shop.
 
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There is another option besides 3 phase.
While 3 phase will run at reduced speeds much better than single phase motors will, you lose power at those reduced speeds.
I picked up a couple of DC gearmotors that have the speed controls built in - plugs into a 120VAC outlet and does the rectification and speed controlling internally, though I suppose I could hook up a remote potentiometer.
DC motor can give full torque at creep speeds if required.
 
With the new VFDs torque is not a problem.

With the VFD I am using and the motor that is wound for use with a VFD I have had not torque issues even down to 10 cycles. My lathe is geared to run 107 RPM in back gear. I have slowed my lathe down to 12RPMs and run it briefly up to 4000rpms. I trty not to run my VFD at more than 150% and less than 50% of the rated 60 cycles.

Nat Labeth
 
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