Brought my SB9 into the this century

Well I just brought my South Bend 9 into the new age. It just got outfitted with a 3/4 hp 3 phase motor and TECO variable frequency drive unit. Thanks to a friend on another forum, the setup went very fast. I actually was surprised how easy the transformation was. The first picture is the old 1/2 hp motor and drum switch system. The rest show the new VFD and motor. The unit will take the lathe from 30 rpm to full speed at a smooth gradual operation. It has reverse also.

very nice but cover that thing up - guaranteed chips and/or dirt is going to make it`s way to the vfd= toasted!

disregard if pics are just to show detail.

I don't understand why you tossed the old familiar drum switch an changed if for a small double throw switch mounted on that stalk. The drum switch can be used just as well as the "new" switch since it doesn't really care if it's switching full motor current in the "old" set-up or low voltage signal level stuff for the new set-up. I've used my old drum switches in all of my VFD conversions which leaves the switch in its old familiar location. The location of the speed pot is less important because you don't tend to change it nearly as often as you start-stop the motor.

very nice. Can you provide a detailed description on the parts and how it was done (since it was a simple mod)?

SE18 said:

very nice. Can you provide a detailed description on the parts and how it was done (since it was a simple mod)?

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1st start here: Dealer Industral Equipment You can also chose from other HP sizes.
They ship very fast. But should at $40+ for shipping!
The only real hard part was sorting the wires on the 3 phase motor. The wire numbers are kind of hard to read, but doable. You have to wire nut together 4 bundles to make the motor a 3 phase, 220 volt motor.
Also I picked up from Radio Shack 271-1715 10 ohm pot, and 275-0654 SPDT (single pole double throw) switch. Your old drum switch could be used for the switch, but I didn’t want to fool with putting little bitty wires on great big lugs and I wanted to keep the old drive whole, in case I want to swap back. Also got a "hobby box" from Radio Shack for the controls, but a standard switch box will work.
The VFD comes programmed for basic operation and seemed ready to run. I just hotted it up before installing the remote controls and using the on board controls sped the motor up to 60 hz (1710 rpm) from the preset 5 hz (100 rpm). After that it's a matter of just selecting through the codes and adjusting a few settings. Kind of like setting a watch. These VFD's can do alot and be controlled by a lot of things, but most of that stuff we wouldn't use since we are the ones controlling it. It is cool how it slowly spins up and back down to a stop, both of which are programable. I was able to cut 8 TPI threads with my lathe at about 30 rpm. Made the job easier to control. Also the chuck won't spin off in reverse since the VFD controls the stopping and restart in reverse. If you need more, I have lots of details about the programming. It really isn't hard to program or hook up. Just don't get heavy wires, the VFD has small lugs on the 1 HP down size.

would this be a viable thing to do to my 10k variable speed sb?

urquidezj said:

would this be a viable thing to do to my 10k variable speed sb?

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Sorry for my ignorance, but how is the 10k variable speed?? If it's just belts and pulleys like mine, then yes, it's can be done easily. Basicly any where you have a NEMA 56 Frame mount area available, the VFD can go there.

1967-68 sb made the 10k with variable speed, has only one wide flat belt going to the motor and speed controller at the bottom of the machine. i dont know if i would need it if it already has a much "older" version of it. looks mighty interesting though

My research has indicated that equipment which already has built in speed control generally is not well served by a VFD. That equipment tends to prefer the pure sinusoidal 60hz.

thanks, Josh