Lathe VFD upgrade - Motor HP?

[Eric Arnsdorff]

I have an older Nova 1624 (I’ll check that but I believe that’s it - 16” and 24” inboard/outboard).
It has a good 1 hp Leeson motor. I’ve never turned large diameter items on it but I’d like to keep the larger capacity as I do intend to try some bowls and such in the future.

I’m going to replace the motor with a 3 phase and a VFD.
I’m interested in if anyone has experience with this type upgrade and if they thought increasing the hp is needed due to decreased torque at lower speeds?

I plan to keep the same pulleys so I can adjust for improved torque if needed.

Is there any reason to go to something like a 2 hp motor to account for the reduced torque at lower speeds?

[Ed Aumiller]

I changed my PM from 3/4hp to a 1 1/2hp with vfd...
Simply because I already had the 1 1/2hp available..

Do not notice any real loss of torque when run it slow...
I often use it to mix gallon cans of paint and run it about 3rpm...
(it is real handy for that!!)

Kept the stepped pulleys on both motor and spindle, but never found need to change via pulleys as vfd does it all...
Use a 1 to 1 on pulleys...

You will be really happy after you change it as it is so easy to adjust speed.. Also you can reverse it easily...

[Eric Arnsdorff]

Correction: It's a Nova 3000
Note: It has the original Leeson 56 frame motor with a 5/8" shaft. It appears Nova upgraded it to a 145T frame with a 7/8" shaft. I think I will go ahead and do this upgrade and use the 145T frame with the 7/8" shaft.

Thanks Ed!
I don't want it underpowered but I'm also a fan of not putting more power there that could do more harm than good. I'm leaning toward the 2 hp drive and the 1.5 hp 145T motor for the upgrade (and my drive pulley bored out to 7/8").

[Ron Borowicz]

I have a Nova 3000 that I upgraded to 2 HP and a VFD about 4 or 5 years ago. I purchased both motor and VFD from https://dealerselectric.com/. Got the whole thing done for under $300.00. I am happy with the 2HP but especially happy with variable speed and forward and reverse. Am I able to stall the 2HP? Yes, but that is during coring or having an especially out of balance bowl blank. I view these stall times as my issues and not necessary equipment issues. (I think it is Reed Gray on this forum that says he can stall his 3 HP Robust if he wants to). I added a extension cord to the VFD allowing me to move the controls to the tailstock end of the lathe. At the time, I received help in this endeavor from a couple forum members including John Lucas.

[Ed Aumiller]

Unless you have a way to bore the drive pulley perfectly, would recommend you buy a new pulley.
If it is the least off centered or at an angle you will have vibration, etc..
Not worth the trouble.. Get a new pulley with 7/8" bore...
You probably do not need a step pulley.. Use a single pulley with same diameter as your center pulley on the lathe spindle.

[Eric Arnsdorff]

Ron that's a great price for a 2 hp setup. I can come close to $300 if I order from Amazon but I don't trust the drive or motor. They may be fine but I'm going to go with what I know works. It's only ~$80 more from AutmoationDirect. I'm very familiar with their products and they have great support.

Ed yes that does become a pain. I can get the pulley bored out (boring bar on a lathe) for free but I'd still need the keyway broached. Also, as I looked further I see that the mounting plate would need modification. It's all doable but I'm not interested in turning this into a bigger project. After almost getting the 145T frame I did change my mind and order the 56 frame. I've not had an issue with the 1 hp Leeson 56 frame motor so I'm hoping that will remain true with the new motor. I considered the option you stated, to replace the pulleys, but once again I'm trying not to let that project creep thing happen into a bigger project than it has to be.