Mini Lathe AC Motor Upgrade

This is not a tutorial on how I upgraded my mini lathe's motor, but rather an explanation on the why. I have been asked many times about the motor upgrade, and I thought it best to make a video about it. The way I went about it may be a little unorthodox but it suits my needs.
The motor is a 390w (1/2HP) AC induction motor that runs off single phase electricity. I originally implemented this as a temporary upgrade when my DC power board that came with the lathe blew and I required a quick fix. However I liked the upgrade so much that it has become my permanent method for powering the mini lathe.
Cheers

[@artisanmakes]

G'day everyone. Thankyou all so much for the feedback. I might have said it but motors and electricity are not a big strong area for me. I apologize if I got a few things incorrect in this video, and thankyou to those who corrected me. Cheers.

[@Dodi-nz3fd]

Please provide the address for this mini lathe dealer/distributor, in *Indonesia* .

[@Lucas_sGarage]

Hey, what's up? Here i will give you some extra points if you are interested, 1 you can purchase a single phase VFD for that motor 2 another option is to use a big brushless DC motor and a large power supply and esc 3 the most obvious one it's to change that motor for a 3 phase motor and use a single phase to 3 phase VFD (which are very common and for that, quite affordable)

[@johndobbie528]

Do you need to remove the internal gears on the headstock, or just lock the lever into the unengaged position, just using the auxiliary motor when heavy cuts are required?

[@TheCommo81]

I'm about to do the same thing with my 7x14 mini. I'm adding a 1HP AC 1 phase motor with variable speed. I don't need reverse. I have a motor laying around that's 1750RPM (compressor motor) so I figured I'd use that. This gives me a better idea, though I'm not going to need the belt pulley you are using to control speed. An AC motor speed controller can be found on amazon for around 20 bucks and they work pretty well. I'm turning my own pulleys and will be replacing the stock bearings with tapered roller bearings and making an oil seal for the shaft so I can just use heavy weight oil for lubricant rather than occasionally adding grease.

[@fredflintstone8048]

You don't need 3 phase power in your shop to run a 3 phase motor on a VFD. The VFD can be fed with a single phase power circuit. The reason this works is that the first thing that the VFD does is rectify the AC power feeding it to DC, and then reconstructs the 3 phase signal from scratch internally at varying frequencies called for according to the speed you want to run the motor. Many VFDs will also allow you to reverse the motor direction on the fly.

[@WmSrite-pi8ck]

ya, i was just about to type this exact thing. i got a nice import vfd for $45 delivered. took about 20 minutes to wire it.

[@fredflintstone8048]

@@WmSrite-pi8ck Nice, that's a good price. What I've seen more of on youtube is lathe owners going to a 1hp 3 phase motor which seems to cost anywhere between 100 - 150, and then a vfd that will handle the wattage for about 100 - 150.. Better to go a little bit higher on the wattage as a buffer, and you might get more and better features as well. The VFDs I was looking at are about 125 and allow all the controls to be set up remotely which is nice.

[@WmSrite-pi8ck]

@@fredflintstone8048 mine is for a drill press so i dont know if that'll work for this application

[@geirkleven3936]

Also, the "one" phase motor is a 3 phase, it just makes the 3. phase from the other phase wit a condensator, It would be stronger also getting 3 phases from a VF single to 3 phase drive

[@fredflintstone8048]

@@geirkleven3936 I've worked a career in the industrial community. Most motors are 3 phase, and the first VFDs were for the industrial market and they were expensive. It seems that the VFD market has continued to produce mostly 3 phase VFDs (inverters). I suppose it would be simpler even with the small inexpensive ones to make them all 3 phase because you could also use them on single phase motors by only connecting 2 legs instead of 3, perhaps they also have an internal setting for that as well to balance out two of the waves. Yes, there are motors that use a 'run capacitor' which is another set of windings that are fed out of phase from the main feed by virtue of a capacitor which will shift the frequency. VFDs are great for getting 3 phase from a single phase source and it works because the supply is rectified to DC first, and then fed to inverters that recreate the 3 phase relationship. The quality of the supplied wave will vary though and some of the cheap ones are a bit hard on some motors because they don't actually produce a true sine wave.

[@cavemaneca]

Great informational video! It's surprising how many people who buy tabletop lathes don't know the options they have for motor replacements.

[@ThantiK]

I happen to have a treadmill motor I've been sitting on for a couple of years, nice to know it now will have a purpose!

[@bobweiram6321]

Have you considered using one of the sub $200 USD sewing machine motors, often sold as "Sewing Machine Servo Motor BLDC." They are incredibly torquey at low and high speeds and beats any AC induction motor VFD or no VFD at the same Wattage. They all come with their own controller.

[@generalawareness101]

I just saw a video about them where they compared and he was burning his hands when he gripped the pulley on it, but the brushed motor easily stalled. Serious torque for sewing leather at low RPM, AND for a lathe.

[@bobweiram6321]

@@generalawareness101 I've been eyeing them for years now and they keep getting cheaper and cheaper. I might bite the bullet and buy one. It would make an awesome CNC spindle motor configuration.

[@davesandersthegreat1]

oh man you are just the BEST! thank you so much! i've been looking for something exactly like that!

[@WireWeHere]

A 1HP ≈ 750W Brushless Sewing Machine Servo Kit 110V Pure Copper Core Motor 500-4500rpm is slightly larger diameter and a little shorter than the stock lathe motor. With a custom bracket it can be fit in the same location. Controller has braking, direction, ramped acceleration, and reversing control. These motors are extremely quiet too.

[@bobweiram6321]

@@WireWeHere Interestingly, the wattage can go even higher.

[@jbsnarayana4938]

well it's a lathe kzbin.infoUgkxN9zrzkkhnjUF5PQbuA_B1gYdsfCu9k6z but it wasn't what i would have anticipated. Headstock, tailstock, carriage apron are manufactured from aluminum now not cast iron. The spindle diameter for the bearings is too small allowing for a few play in the spindle so I am using some blue Loctite to take out the play.

[@mzb8134]

For anyone looking at this upgrade, consider a gates polyflex belt. With the appropriate pulleys you can get 8 ratios in a small package. My lathe gives 8 speeds between 360 and 2820rpm off an AC motor.

[@peterjackson6706]

nice and compact

[@garymucher4082]

I understand your reasons for your motor selection. However, everyone has different needs and wants for their motor for their lathe. A quality variable speed motor with a equally quality speed controller circuit can and does work flawlessly for years. It is all in what you want for your needs. Thumbs Up!

[@shinymud7]

Treadmill motors have speed control built in.

[@ronbianca1975]

Howdy! If you don't already you may consider putting the rear mounting of the motor on a hinged platform. It makes changing speeds easy. Keep up the good videos!

[@artisanmakes]

A really good suggestion with the hinge idea, I'll have to steal this if I get a spare hour or two. Thankyou

[@DanielAbdelsamed]

Correct me if I'm wrong, but isn't one of the functions of a VFD to convert single phase power into 3 phase? For my CNC router I have a single phase input to the 110V VFD, and out comes the three phases for the motor.

[@MarkATrombley]

I believe there are several types of VFD, but one type takes single phase in and puts 3 phase out.

[@UncleKennysPlace]

The primary purpose of a VFD it to vary the frequency. I've built a 110v single phase VFD that controlled a straight 110v single phase motor. Not efficient, power wise, but it works. Edit: this was before cheap single-to-three-phase VFDs became available!

[@fredflintstone8048]

All VFDs will run on a single phase supply or a three phase supply. The important thing is to get the supply voltage within spec, and that the circuit be able to handle the current load. The reason you can feed VFDs with single or three phase power is that the first thing in the VFD circuit is a full wave bridge which converts incoming AC power to DC. The full wave bridge is made up of 6 diodes, one for each phase. Feeding it with single phase leaves one of the input legs and pair of diodes unused, and this poses no problem at all. I've done this many times with many different kinds of VFDs for several decades.. It will cost more, but the best lathe upgrade is a VFD and a 3 phase motor.

[@aleksandererga2319]

Hi, there exists vfds that take single phase, and creates a 3 phase current.

[@gregwmanning]

As stated below single input to 3 phase output is normal for VFD plus vfd will give the reversing function. One day I am gunna put a single phase motor on the output of a vfd and see what happens... It is possible to reverse a single phase induction motor ONLY IF the four (or six including the centrifugal switch wires) winding wires come out to the connection box. Most industrial type ac induction motors (like yours I think) are capacitor start motors with two windings. A main winding and a start winding with the capacitor and centrifugal switch in series. You need to reverse the connection if the start winding to reverse the motors direction. Having said all that, most single phase ac induction motors only have 3 wires coming out to the connection box and cannot easily be reversed. The main and start windings are joined internally with the junction wire plus the other end of each winding coming out. You never know unless you havalook in your connection box.

[@cavemaneca]

FYI, generally VFDs are designed to function with some sort of feedback on all 3 phases and can be damaged if you don't hook up all 3 wires. I've tried it at work with old VFDs nobody would miss though, and it did as expected though the motor had a lot less torque than just a direct connection.

[@gregwmanning]

@@cavemaneca Thanks for that. Did you a vfd 3 time the rating of the motor? If not, maybe the VFD could not supply the motors required current thru a single phase, particularly start current?

[@GlennNowOnYouTube]

A lot of good info in this video, Thanks for sharing.

[@Pushyhog]

So your motor is so heavy it just sits there? Not bolted to table? Thanks great if so. This is the best and most helpful yt you will ever make.

[@Flying0Dismount]

I've hooked up a single phase VFD outputting 3 phase to a single phase 2 HP induction motor for my belt grinder. No, not in the way you might think (using one output phase out of 3- this doesn't work with all VFDs, many will trip a protection circuit if the phases aren't in reasonable balance).. In my case, I had a capacitor start motor where both the run and start winding were identical (same gauge wire, same # of turns), so as an experiment, I took out the cap as well as the centrifugal switch and wired the motor windings in an L config and hooked up the VFD as if the motor was a delta with an open winding and calculated the appropriate voltages and programmed the VFD, and the stupid thing actually runs.. It lugs a bit slow speed, but I can get it down to 8 rpm and it still has full torque and I can't stall the belt and even though there's 1/3rd of the motor effectively missing, the phases are below the imbalance trip threshold so the VFD is still happy and I doubled the high speed limit from 1800 rpm up to 3600 rpm for hogging metal... So there are many ways to get motor speed control to work, even some unconventional means...

[@JustinTopp]

You could use a three phase motor still. There are plenty of vfds out there that able to convert single phase input to three phase output

[@guitarchitectural]

If you cut a lot of acrylic, have you ever tried a tangential tool.holder? That would help your cut quality a lot!!

[@markhubanks3715]

I really like your idea but my question is, since you pulled the motor and pulley attached to it from your drill press, couldn't you just use the pulleys off the drill shaft and re-work them on your lathe spindle? This would give you multiple speed settings over a broad spectrum from very high rpm to a low rpm. Thanks!

[@Pushyhog]

i did this and now doing steve jordan channel mandrel in spindle with 6” & 5 inch pulley. So now l have both mods when needed.

[@brassaap]

If you use a common condenser start motor you can easily reverse switch it. Just watch the pulley doesn't unscrew in reverse

[@loginavoidence12]

"Insulation class" is what you're looking for on ac motor. it's longevity directly related to the avg temp it operates under. it should be a letter on your nameplate, A - H

[@a3d888]

Can I ask you something please, my country and all countries in the world use the AC electric power how does the lathe DC motor will work on my power switch do I have to buy some kind of AC to DC adapter? Or the DC motor got build in inverter from AC

[@odingarberggule9693]

Its buildt in, just need to plug in the cord from the lathe into the wall

[@johnnodge4327]

The built in control board converts AC to DC, in the same way a USB adapter turns mains AC to 5 Volts DC. ;)

[@pettere8429]

How do you get 1800 rpm on a 50Hz induction motor? The synchronous speeds for 50Hz are 3000rpm and then 1500rpm, and then the slip will slow down an induction machine a few percent at rated torque.

[@janguitar8499]

Do you think a 250W lathe is able to cut steel?

[@fredflintstone8048]

I would say in general yes, but it's going to depend on a number of factors, the tool, the speed of the chuck and how the motor creates that speed, the amount that the tool is attempting to cut at once, and the attempted cutting depth.. You will have to take your time.

[@jimsvideos7201]

They will, take your time, keep your fingers away from the chips.

[@artisanmakes]

As others have said, maybe mild steel, but it would take a bit of time and you would need to stick to hss tools. Cheers

[@donmittlestaedt1117]

Thank you for the video.

[@Lucas_sGarage]

Question... Why u didn't use a 3 phase induction motor and a VFD?

[@Juan-nm4gp]

It was what I was looking for, I have a similar lathe and I'm about to mount it with a single-phase motor with a 6-pole switch for reverse, you would have to try it. Greetings. I use a translator, my English is terrible

[@ryanr3618]

What pulley did you use on your lathe spindle for the belt? Dimensions? How many teeth? What size belt, how many teeth? What's the groove rating? Links?

[@artisanmakes]

It's a standard k30 v belt, no teeth. The friction of the pulleys is enough to drive the spindle and in the event that I crash the tool into the machine the v belt will slip and prevent it from potentially snapping. And it's much easier for me to machine custom v belts in-house than having to index and machine teeth.

[@ryanr3618]

@@artisanmakes Please make some more Mini Lathe videos, they're great

[@ryanr3618]

@@artisanmakes Do you remember the inner bore diameter of the pulley you put on the spindle?

[@And3rs88]

I'm surprised no one has tried closed loop speed control of these dc motors, whether brushed or brushless. I have no trouble doing wide groove cuts on my 350w brushed mini lathe but my hand is on the "speed" dial cranking up the power to maintain a steady 100rpm or so while also feeding the cross slide. That's the problem with dc motors however, to maintain rpm under load power needs to increase but it can't do this on its own. AC induction motors on the other hand naturally pull more current as load is applied to maintain a fixed rpm, coupled with the fact in thus set up the motor is running at peak torque constantly with gearing to adjust spindle rpm.

[@ThanasisThomas]

Where did you buy the spindle pulley?? did you buy it or did you make it urself?

[@artisanmakes]

The pulley I made from a piece of 50mm diameter aluminium. The belt is a common k30 v belt

[@ThanasisThomas]

​ @Glenn Howe

[@GlennHoweTeam]

@@artisanmakes Is the pulley threaded on or is the ID just large enough to slide over threads? Thanks

[@Lucas_sGarage]

And also, there are some VFDs that can operate single phase motors, check ATO VFDs

[@MyMartinL]

Hi, your motor is 3 phase. The bulb casing houses a capacitor to convert it to’single phase.

[@artisanmakes]

Thankyou for the feedback. The more you know eh. Thankyou for correcting me.

[@samkaplitz9036]

Single phase motor shown.

[@kennethcolbert2921]

Where did you get the pulley for your mini lathe? I can"t find one to fit my mini lathe here.

[@mans4104]

There are VFD 1Fase to 3Fase output. eBay 2HP 1.5KW VFD SINGLE 3 PHASE SPEED VARIABLE FREQUENCY DRIVE INVERTER INDUSTRY 8A .

[@ThanasisThomas]

Did you make the spindle pulley yourself?

[@GlennHoweTeam]

I too would like more information on the spindle pulley. Aluminum?

[@noviceartisan]

Just realised, you know you could use a triac as a speed controller right. E.g. a light dimmer switch ;)

[@reneemakesthings]

They are less than ideal at low speeds.

[@noviceartisan]

@@reneemakesthings Fair, but you'd not need as much torque at low speeds when cutting threads?

[@reneemakesthings]

@@noviceartisan Nah - the exact opposite. You need ALL the torque to cut threads at slow speed. The force on the tool tip is very high when cutting slowly (Have a look through ABOM and Joe P's videos for more detail), and that force needs to be balanced with the energy input. The triac method works by reducing the amount of power going into the system, but in a very loosely controller manner. The energy pulses are always spaced at 100Hz, so at slow speed, there will be a significant dead-space between those pulses. It's in those dead-space where the motor can stall, or be over loaded. This is why small lathes use either a brushless DC motor (with a controller running at 50-150kHz) or a VFD induction motor - they have much smaller dead spaces in the power delivery cycle.

[@calholli]

You should really put a big sheet metal shield of that motor.. give it a little space so that air can still get into the motor easy, but the shield can block all of the debris that is flying off of the lathe. Letting all those chips and dust go right into your motor is a good way to kill it fast.

[@artisanmakes]

Not a huge issue for induction motors, had it this way for over a year and a ha and I've never had issues

[@calholli]

@@artisanmakes I get that...but you're throwing metal chips into open holes where there are coils of wire. If you keep letting it get caked with dust, eventually it would overheat when you actually run it hard. Even if it takes years, there's just no point in taking that risk when a simple piece of sheet metal or even plastic could be mounted over it.. Super simple.... We could drive our cars without air filters and it would work fine-- but it doesn't make it a smart thing to do..... I mean hell---- Just lean a cardboard pizza box over it. done

[@RepLicanT00100]

Drum switch could reverse the direction I thought .

[@rf9418]

the ac motor, what rpm have ? 2800/1400 ?

[@artisanmakes]

Mine is 1400

[@noviceartisan]

Sweet

[@Pushyhog]

guess your still using it?

[@Pushyhog]

please tell me correct motor, went to buy one, he said how fast does it turn, go find that and come back, Can u list whats on side of motor?? l want what u have. DATA PLATE please. Artisan gave me a tip: get 1 hp A/C motor.

[@yveslegrand9826]

The minilathe is really lacking torque at low speed. Both the motor and the drive belt are a bit too small for my taste and the low cost (no gearbox at all) version is thus limited in size and speed (low end). My first move was to make a DC driver with a good speed stability (using some type of speed sensor for a feedback loop). But an other type of transmission is a must and then going for a bigger motor is probably making more sense.

[@Dodi-nz3fd]

Please provide the address for this mini lathe dealer/distributor, in *Indonesia* .

[@Pushyhog]

so, having no reverse does not matter? Thats what l want: on off switch. No mother boards & controller.

[@artisanmakes]

Not for me, at least at the time when I did this upgrade. No control board, and when I stall the motor, once I pull the cutter back it springs back into life. No resetting anything. Cheers

[@Pushyhog]

l have about completed your install of plain ac motor with 4 banger pulley. Gotta make alum pulley on motor.

[@intotheblue50]

Great video but I find it hard to focus on your words with that music in the background.

[@artisanmakes]

Thanks for the feedback, it is always a difficult balance to find

[@generalawareness101]

Every mini lathe I found on eBay, that were sub 1200 and actually said, were all brushed. UGH!

[@keatoncampbell820]

Wow so I shouldn't put a hydraulic motor directly geared into the headstock. I figured itd have great low end torque, and it would be adjustable... But I guess I could shred all the gears lol

[@artisanmakes]

I'm sure you could find a way to do it, since the motor directly drives the spindle it won't put load on the headstock gears, only the leadscrew.

[@ryebis]

If you don't want to spend $250-300 on a VFD + 3Ph motor solution, sewing machine motors are a reasonable compromise. www.ebay.com.au/itm/333430509304. I have a 10x20 and I replaced the stock 1Ph 750w motor with a 600w 3Ph + VFD with vector control. I overdrive the motor with 2:1 pulley reduction to improve the torque, has been fine so far.

[@tcratius1748]

That's weird, I thought VFDs emulate three phase power kzbin.info/www/bejne/l6G0fJqplKljeq8 And what kind of lathe did you buy?

[@artisanmakes]

G'day, my understanding is that vfds don't work with 2 phase AC induction motors, but I was not aware that vfds could emulate 3 phase power. The late that I bought is a 7x14 Sieg c3 mini lathe. Cheers

[@tcratius1748]

@@artisanmakes I also like watching this lady as she is excellent at breaking down and explaining tasks on the lathe and mill. She has a whole series on beginning stuff, which is where I'm at and has projects that you can get the plans. kzbin.info/www/bejne/j6CxkICJqtate5I

[@AdaptingCamera]

Where did you get this from...? kzbin.info/www/bejne/f2i4hpKDpMacm6s I mean that "single phase AC don't work well with VFDs" statement is pure nonsense. Single phase AC works very well with VFDs if you buy a VFD made for single phase use. In fact, it is very common, and a good reason to buy a VFD in many places, where three phase is not available. There is no reason to confuse your viewers with such statements, especially for hobby use, it is an excellent way of generating three phases to enable use of 3-phase motors. I dare say that your solution is MUCH worse than using a VFD and a 3-phase motor, but considerably cheaper.

[@qadoqados4354]

Руки намотает на ремень.

[@clutch5sp989]

If you need all the options & speeds etc etc....buy the right machine for the job instead of constantly jerry rigg'n the poor lil lathe. Seriously...a motor driving a shaft with a chuck on it to turn simple parts doesn't need all that many bells & whistles.

[@Frank0games]

first