New motor for Powermatic 45

Re: New motor for Powermatic 45

Roger D. Coates

>Brian,

I just installed a Baldor 1 HP, AC motor with variable frequency drive (VFD) unit on a Vicmarc VL100. Total cost was around $625 for the motor and VFD. If you go this route, be sure the motor you buy is inverter ready. The motor I bought was a Super E model, 220 V, 3PH, with constant torque at a 20:1 variable speed ratio, meaning the motor can be operated safely from 1725 RPM down to about 100 RPM without over heating. The VFD, also made by Baldor, is a 15P series. Input voltage is normal 110 V, 1 PH house current with output of 220 V, 3 PH to drive the motor. My advice is to go to your local electrical industrial supply dealer and ask to talk to someone with some technical knowledge about your needs. The wiring can be a little tricky if you're inexperienced in working with electrical components. By the way, these are basically the same electrical components Delta used on their new 1642 series of lathes, just a larger HP motor.

Respectfully,

Roger

Re: New motor for Powermatic 45

Joel Hunnicutt

>I put the 1 hp on my Nova and wished I had gone with the 2. I don't stall it very often, but if I'm out at 14 inches or so, I ahve to take a light cut.

Thanks Roger and Joel! (LONG)

Brian Roberts

>I appreciate your help!

I assume the ratios mentioned are reduction ratio (at full torque and with no motor overheating) - i.e. a 10:1, 1800 rpm motor could be run as low as 180 rpm with no problems.

The packages (that interest me) that D.I.E. offers are:

1hp, 10:1 for $290

2hp, 10:1 for $385

1hp, 1000:1 for $372

They also have a 2hp, 1000:1 for in the $600 range but this one is a different frame size.

The following all assumes a motor speed of 1800rpm, like my original, but the ones they sell may be 1725rpm - don't recall.

The 1000:1 will (supposedly) get down to about 1.8rpm with no loss of torque and no overheating! Can't imagine needing to spin that slow - am I wrong?

So... I'm thinking.... I can get the 2hp, 10:1 for about the same price as the 1hp, 1000:1. I like the idea of having the 2hp and with the 10:1 motor I should get 10% of my existing speeds, or a slowest speed of about 60rpm.

If my thinking is correct the new setup should give me:

1st step 60 - 600 rpm

2nd step 111 - 1110 rpm

3rd step 180 - 1800 rpm

4th step 300 - 3000 rpm

The lowest rpm I can get now, with the step pulleys is 600, which is screaming with an out of round, large diameter log on the lathe! The potential to get down to 60 rpm seems like a dream to me! Is there a need to go slower??

Many thanks!

Brian

Re: New motor for Powermatic 45

Rick R, So Cal

>Brian,

Keep in mind that with your current mechanical speed change, you're getting nearly 3/4HP (minus pulley drive losses) regardless of speed range. With electronic variable speed, you get proportionately less HP as you turn down the speed, at least with DC systems. VFDs on the other hand will typically have constant torque/constant HP regions depending on the RPM. Simply put, there is a point on the speed control knob (about half way) which will give you full HP. Below that point, you're in the constant torque/variable HP region, where you would get less than the motor HP rating.

So if I were you, I would either get a 1.5HP DC if you can get it really cheap, or go with a 1HP minimum VFD system, keeping in mind that you will get less than 1HP at the lower speeds.

Rick

Re: New motor for Powermatic 45

Brian Roberts

>Thanks Rick! I love this place - each reply gives me a little more of what I need!

So my thoughts in my second post, as far as getting the 2hp, 10:1 setup (these are packaged motor and VFD controller for the prices I listed) might be the better choice, assuming 60rpm is slow enough, to ensure sufficient available hp? I guess picking the right pulley step would be important too - the faster the motor turns, at the speed I want, the more hp?

They do have a 3hp, 10:1 for $438 - worth the extra $$$ for the extra hp???

Thanks for indulging my variable speed ignorance!

Re: New motor for Powermatic 45

Rick R, So Cal

>Brian,

I have the PM3520, with 2HP VFD. With only 2 speed ranges, 0-1200 and 0-3000, I have never had a need for more power, and I have turned stuff that was too heavy for me to lift. I think the drive belt on your PM 45 will be the limiting factor; it's going to slip before you can develop 2HP, so going to 3HP would be a waste. I suggested 1 HP since you didn't feel the lathe was underpowered with its current 3/4HP motor.

The VFD that you are referring to goes down to .1Hz, just like the one on my lathe, so you should be able to get spindle speeds down close to zero. Two speed ranges should be all you need, low for big bowls and high for spindles.

Once you go to variable speed, you will never go back, and you will want it for your drill press, grinder, flex drive, vacuum pump... that's what happened to me!

Rick

Re: New motor for Powermatic 45

Brian Roberts

>Thanks Rick - I guess I can add variable speed lust to my other afflictions - wood lust, tool lust, shop time lust, etc., etc..

I hope you folks don't mind me using your names when explaining this new problem to SWMBO.

Brian