3 phase lathe

captainjko

Kirk
Silver Member
Anyone using a 3 phase lathe with a phase converter? I found a decent deal on a 13x40 lathe but it is 3 phase. I’ve never messed with a converter. Is it a simple install? Thanks in advance.
 

HQueen

AzB Silver Member
Silver Member
I tried one 20 years ago on my first lathe. Did not run right. Ended up swapping the motor out for a single phase 220.
 

CroweCues

AzB Silver Member
Silver Member
............

Running a Sheldon Exl 56-B on a phase-o-matic static converter. cheap route converter wise. Rotary converters work great but can get pricey. When done right, can be a huge advantage when buying/pricing machines. Also, look and make sure how its wound, If you can. should be on the motor. 240 3 phase, or dual wound if what youre looking for. most are (older ones) dual wound, so no issues normally.
 
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Mike81

AzB Silver Member
Silver Member
Anyone using a 3 phase lathe with a phase converter? I found a decent deal on a 13x40 lathe but it is 3 phase. I’ve never messed with a converter. Is it a simple install? Thanks in advance.

Static converters are junk. Don’t waste your money. If and when then they do work you’ll only get 60 percent of the rated horsepower of your machines motor. You also cannot take advantage of the three phase motors instant reversing capabilities. A rotary phase converter is the way to go, especially if you plan on buying machinery in the future that is three phase. They can be pricey but if you shop around you will find a deal. They are easy to install also and will use less electricity when running than than 220 single phase motor or a static converter. You’ll also have the capability of running multiple machines at the same time assuming of course you select the correct size. Then again switching to a 220 single phase motor may be a simpler approach
 

whammo57

Kim Walker
Silver Member
I bet you can change the 3 phase motor to a single phase motor for about the same price as a converter.

Kim
 

63Kcode

AKA Larry Vigus
Silver Member
I am running a few lathes one a rotary converter. Wiring is easy with basic wiring skills. Two things to look out for is voltage. My first lathe was set for 440V. It was an easy swap at the power supply to change to 220V. Second thing is having the lathe controls wired to a shop power leg and not to the rotary power leg. Operation will be jerky if you wire the controls to the rotary. Swapping wires will solve to problem..

Larry
 

iusedtoberich

AzB Silver Member
Silver Member
Wouldn’t a VFD be in the running? You’d get the phase conversion, plus variable speed. I believe their prices have come down significantly over the past decade.

*I have never installed one but use them on some machines at day job.
 

captainjko

Kirk
Silver Member
Wouldn’t a VFD be in the running? You’d get the phase conversion, plus variable speed. I believe their prices have come down significantly over the past decade.

*I have never installed one but use them on some machines at day job.

Can you share with me a link to what a VFD is?
 

Ssonerai

AzB Silver Member
Silver Member
Most of my machines are 3ph. It just allows you to buy so much more industrial quality machines.

From a lathe perspective, not that a cue-maker would notice :grin: 3ph gives smoother power delivery, which in metal work sometimes matters. IOW, sometimes cheap single phase power gives a "phonograph point" effect on material, where 3ph would not. From a machinist perspective, 3ph is also plug reversible, which can be useful on production tapping and such. (don't use screw on chucks, lol) This probably has no application for cues. There's no capacitors to blow in a 3ph motor, and wiring one is simpler than single ph in terms of reversing rotation for the app.

If you are electrically congnizant, the cheapest way to use 3ph is to home-brew a rotary. All you need is a surplus 3ph motor of about the same size or larger (HP) than the one you want to drive. If you can get the 3ph idler motor turning, it will generate the 3rd leg and power your other 3ph machines almost seamlessly. In the metal shop, my idler is pull start, just like an old lawnmower. I wrap a few turns of a pull rope around a flywheel on the end of a motor on the floor in a corner, give a steady pull ending with a wrist snap as i straighten up, and turn on the disconnect above my head. If i had enough speed, the idler starts, and is wired into all the other machines in the metal shop.

In the wood shop, i use a capacitor bank (like a commercial rotary) so when they are activated (when a switch is thrown), the motor starts, then the capacitors are removed from the line (capacitor bank pushbutton pushed to de-activate the starting caps). In the wood shop, the 7.5HP idler is then wired into a regular 3ph load center ("panel box"), and distributed by normal wiring to all the 3ph machines.

There are some things to finess if you have access to free 3ph motors, so the above is just a hint for further research.

All that said, I put a VFD on the lathe cobbled together from parts for my cue lathe. Seamless variable speed, easy install, programmable for some other functions, such as how fast it starts or stops.

Also have a VFD on the planer i use with centers, for my profile machine for cue shafts. In low cone on the belt drive, with the VFD it can get down to where the table just creeps along under a router in the toolslide at inches/minute if desired. When using the planer as designed, in high cone the table can be over-driven to something over 60sfm, say for planing steel.

VFD's are great for anything that needs variable speed.
 
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Mike81

AzB Silver Member
Silver Member
Remember this if you plan on using a vfd, a vfd changes the hertz of the motors to regulate speed. So this is hard on the windings or I should say the wire used to make the coils. Most newer motors are wound with inverter duty wire which can handle the frequency changes but be careful if the motor is an older unit, it may not last long hooked to a vfd.
 

Mike81

AzB Silver Member
Silver Member

Yes but shop around. I paid 1200 for a 220 rotary phase converter that was a 15 horsepower motor. It was capable of running motors that were 7 1/2 hp and less. It was a few years ago but shouldn’t be much more today. Check with a local electric motor repair shop to see if they could help you. They are fairly easy to make
 

captainjko

Kirk
Silver Member
Yes but shop around. I paid 1200 for a 220 rotary phase converter that was a 15 horsepower motor. It was capable of running motors that were 7 1/2 hp and less. It was a few years ago but shouldn’t be much more today. Check with a local electric motor repair shop to see if they could help you. They are fairly easy to make

So is the unit listed on eBay all that I will need.? Or is there something else that goes with this unit?
 

Mcues

AzB Silver Member
Silver Member
Anyone using a 3 phase lathe with a phase converter? I found a decent deal on a 13x40 lathe but it is 3 phase. I’ve never messed with a converter. Is it a simple install? Thanks in advance.

All I can tell you, is that I've been running a Static Phase converter for about 15 years on one of my lathes. You'll be running at about 66% power but on a large metal lathe is more than ample for all cuemaking duties. I think the price was $125. at the time. The lathe is an old 11x37 Delta Rockwell.

If I was running more than one 3 phase machine then I would go for a Rotary converter.

Mario
 

Ssonerai

AzB Silver Member
Silver Member
Remember this if you plan on using a vfd, a vfd changes the hertz of the motors to regulate speed. So this is hard on the windings or I should say the wire used to make the coils. Most newer motors are wound with inverter duty wire which can handle the frequency changes but be careful if the motor is an older unit, it may not last long hooked to a vfd.

This is a reasonable caution. But usually not a factor. The 3HP 3ph planetary gearmotor on my planer/shaft profiler was built in the 19-teens and runs fine from about 9Hz through 99 Hz.

A VFD maintains essentially constant torque throughout the frequency (speed) range, but hence by definition loses HP as the speed diminishes. So for very wide speed range, it is useful to have a gear box as well. Sort of like a set of ranges, within each of which the speed is infinitely variable. However, trying to decrease the speed on the hi-range gearset loses more power, than running the low range gearset at a faster motor speed. Obviously a gearbox is part of the package with a modern-ish metal lathe. Point being, if the VFD seems to lose power when running slow in a high gear, use a lower gear and run the motor a little faster. Still fully variable speed within the range.

If overspeed is a consideration, VFD's can be set (programmed) to not exceed a certain value. They also have built-in motor protection. (Overload protection).

On the idler motor Q - You still need good heaters (overloads) across all the contacts in a switch set. But an idler of about the same size as the driven motor will start and run equivalent and even larger motors without a problem, so long as they are unloaded when starting. IOW, if you want to run a compressor, the idler needs to be about 2x or 2.5x the size of the driven motor since it might occasionally start under full load. If you want to run a tablesaw or lathe that do not have a load when starting, the idler can be about the same size.

Don't take my word, though, do some research to make sure any package meets your needs.

smt
 

Mike81

AzB Silver Member
Silver Member
So is the unit listed on eBay all that I will need.? Or is there something else that goes with this unit?

I think this would be all you would need but can’t say for certain because I never used one of these before. I may just be as cheap to just find a 220 single phase motor to run the lathe with. If you plan on buying more machines in the future that are 3 phase then the rotory converter would be the way to go in my opinion
 

captainjko

Kirk
Silver Member
I think this would be all you would need but can’t say for certain because I never used one of these before. I may just be as cheap to just find a 220 single phase motor to run the lathe with. If you plan on buying more machines in the future that are 3 phase then the rotory converter would be the way to go in my opinion

Thanks... I do not plan on getting any more machines as this is just a hobby.. I have been using a Porper B but I am wanting a larger, more accurate machine and found this 13x40 for $1500
 

Mcues

AzB Silver Member
Silver Member
Thanks... I do not plan on getting any more machines as this is just a hobby.. I have been using a Porper B but I am wanting a larger, more accurate machine and found this 13x40 for $1500

Is the lathe variable speed?

Mario
 

captainjko

Kirk
Silver Member
Is the lathe variable speed?

Mario
This is a picture of it. It has different speeds.
09232038-4505-49A7-B6D1-8BEFB97BF9EB.jpg
 
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