Cheap DC retrofit?

Seems nearly ideal for a 9"....
Enduro Elite Servo Motor SM15-2 Controller w/ Gear Reducer & External Motor | eBay

seems to be 1400 watts...
Enduro Elite SM1-2

hopefully those more knowledgable than me will comment on the pros and cons.

Yabut... How hard is it to find the rest of the Industrial Sewing Machine it runs?

IF.. I had a SB lathe to power - say 9" or 10"?

- Wherein a 3/4 HP 3-Phase single speed is the sweet-spot so long as all belted and geared ratios remain

- AND for variable-speed one can simply DOUBLE rated HP to cover drop-off at low RPM for VFD'ed AC or at high RPM for DC on DC Drive,

- AND VFD have already been "done to death" and not my rice bowl anyway, even if I DID eat rice..

- THEN, for smooth, sweet, "mini-10EE" running, I would use a KB-Penta 240D 4Q regenerative DC Drive in the neat and handy NEMA 4X housing:

KBRC-240DBLACK - KB Electronics - DC Drives | Galco Industrial Electronics

and

- a motor such as the 1.5 HP Reliance RPM III Stabilized Shunt 180 VDC model of this sort:

RELIANCE 1.5 HP RPM III DC MOTOR, 1750 RPM, FR-XC1811ATY, 180 VOLT | eBay

Take note that the Reliance motor is 280 lbs Avoir on pallet, the sewing machine motor 15 lbs.-minus in cardboard box.

All muscle, that greater mass. Torque. Not fat. Just look at the shaft diameter.

Sewing machine motor might not be such a bad idea after all, given the chronic Iron Deficiency Anaemia South Bend's have in their Levi's.
Genes, that is.

Might want to find a "relieving attachment", too. Sewing machines are notorious for their incessant "self fornicating" motion.



Kidding aside?

You'd want only a 1/2 HP RPM III 180 VDC shunt motor for an SB.

I'm not sure enough were made in that low a HP to be able to find one, though.

You may want to look at this thread.
https://www.practicalmachinist.com/vb/south-bend-lathes/eliminated-all-gear-train-noise-191190/

Vlad

I guess I'd have to ask "What difficulty are you trying to solve?" At first glance it looks as if these are candidates for drive motor replacements but a gear motor suggests elimination of the jack shaft, belts, and pulleys. I've been down the DC motor and the VFD paths and I'd say without hesitation that the VFD solution results in a smoother and quieter drive than the DC motor UNLESS the DC motor also uses a sophisticated PWD drive with the ability to adjust things like acceleration/deceleration rate and an accurate speed control. That, of course, equates to an expensive drive system. But without knowing what your goals might be, it's hard to say.

The motor claims to operate up to 3.7 foot pounds, and at 5000 rpm that would be 3.7 hp.

1400 watts is 2 hp, so its possible their claims are correct and the drive is power limited (but not current limited, due to the nature of a pwm drive) (120v 15 amp outlet?).. or they may not be.

Similar performance would require a 3 hp 3600 rpm motor and 3hp vfd. Torque will drop off above 3600 rpm but that probably doesn't matter, such a package would be hard to find for less than $208.


Anyhow for a southbend 9, those lathes shipped with 1/3rd hp motors for a couple reasons but one of them is: that's the limit for the strength of the back gear teeth, allowing for a 2:1 overload when stalling the motor without breaking the teeth.

If you want to avoid using the back gear completely, I believe it is reasonable to cut V grooves in the cone pulley and use a 4:1 or 5:1 belt drive using a micro V belt and directly drive the spindle from a 2 hp 1750rpm motor. This should deliver enough torque (especially if overloading the motor via a 3 hp vfd) but you will still need to change the belt unless you run the motor out to 6000rpm for a 4:1 ratio. at 6000 rpm the motor should still deliver 1/2 hp.

I would not dream of trying to eliminate back gears...or a countershaft for that matter.

But *maybe* one could design and fab a new countershaft around one of these little servo motors.

a modern compact version of the "self contained" unit if you will.

Don't think I will be doing too much from this chair but it's good to keep the mind active anyway.

iwananew10K said:

I would not dream of trying to eliminate back gears...or a countershaft for that matter.

But *maybe* one could design and fab a new countershaft around one of these little servo motors.

a modern version of the "self contained" unit if you will.

Click to expand...

"Self contained" isn't always a good thing. I'm still trying to get the massive smoke cloud Johansen just tried to blow up my ass to dissipate.

Somehow he's gotten a tiny sewing machine motor into a whole 'nuther universe of 3 HP iindustrial motors off the back of his numbers games.

Good luck making chips with the one, or not tearing the machine to flinders with the other.