VFD and pulleys

Re: VFD and pulleys

Joel Hunnicutt

>What is the frame size of the motor. I put a 56c on my woodfast and I had enough shaft lenght. Mine has 4 step pulleys, not 5. I have AC var, not DC var, but I would be concerned about full torque in the lower half of the range where you will be doing most of your turning. Maybe 2 step pulleys with a speed range of say 0 - 1200 and 0 - 3000 would be the answer. FWIW I leave my pulley on the 1200 setting almost all the time.

Re: VFD and pulleys

John Lucas

>Gary

I did roughly that on an older lathe. I only had room for a 2 step pulley on the VFD motor but it has so much more torque at low speeds that I hardly ever changed the belt.

Re: VFD and pulleys

Mark Kauder, Phenix City, AL

>Gary,

IMHO you would do better setting it up for 1 to 1 or 2 to 1. A DC motor produces higher torque and higher RPMs. If you are going to use this lathe only for bowls, you will not need over 1750rpm. You could set it up with a two step on the motor and a single on the headstock so that you would have a 0-875 and a 0-1750.

Just my opinion. My experience with my Vega that goes up to 2200rpm, I never get any where near that high.

Mark

Re: VFD and pulleys

Steve Mushinski

>Read up on your VFD manual. I would set the lathe up for 1:1 or less as you can have the drive do the work for higher speeds.

Running the drive at 60 hertz will produce 1725 rpm at 1:1.

Running the drive at 120 hertz will produce 3450 rpm at 1:1.

I have mine geared down to give me more torqe and a top speed of around 2500 on a 1800rpm motor.

It also depends on what you are doing with the lathe. Large out of round bowls you want low speed. Small spindle work you want high speed.

It also depends on the motor. My motor has a 10:1 torque ratio. Meaning the motor must be runnning 180 rpm to produce full torque. But I find I need to run the motor at around 250rpm to get good performance out of it.

Steve

Imagine my surprise!

Gary Evans, Tallassee, TN

>Thanks everyone for your input.

If you've ever put the saw chain on backwards (which I did just the other day,) then you'll know how I'm feeling right now. Close inspection of the pulley diagrams on the lathe so that I could start calculating drive ratios showed that I was trying to mount the step pulley on the motor in the wrong direction! 8^{

I guess I could plead a senior moment, but some of you wouldn't buy off on that. Boy, I'd hate to be in my shoes right now!

Anyway, now we can proceed with the motor and drive installation. Hopefully I'll have some finished work to show on here before too long.

Thanks again~~~with a red face,

Gary

Re: Imagine my surprise!

Mark Kauder, Phenix City, AL

>Know how you feel, Gary. A couple of weeks ago, I put a different blade on my TS, and was starting a cut, and it was smoking like hell. Since it was just some rough cut anyway, all I though was - "Damn, I have to get this one sharpened". When I went to put a different "Sharp Blade" on the TS, I discovered that I had put the TS blade on backwards.

DUH

Mark

Re: Imagine my surprise!

Gary Evans, Tallassee, TN

>I've done that one, too, Mark. This just seems to be my time for that type of dyslexia. Anyway, I hope to have the Woodfast running by the end of the weekend.

By the way, did your piece work in that customer's room?

Gary

Re: Imagine my surprise!

Mark Kauder. Phenix City, AL

>She just called me a couple of hours ago, and said no and is sending it back to me. Though she did not commission me specifically for one, I will be emailing her pics of ones that I finish in the near future.

I have hopes that she will pick one.

Mark