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Looking for 2 Speed Motor for 13" SB

mathamattox

mathamattox

Aluminum
Joined
Nov 1, 2009
Location
Charlotte, NC
Guys,

I have been on the lookout for a 2 speed 2hp or 3hp motor for my 13" Southbend lathe. If anybody has one they'd like to sell let me know. The one in the lathe now is a frame 145T, not sure if the next larger frame will fit (182T ?).

Thanks,

Jonathan
 
A transformer and VFD is an inexpensive method to achieve what you want.
After years of searching for a dual speed 220v 2hp motor single or 3 phase I gave up and used the original 440v motor. Here is the post

There are 2 speed 220v 3 phase motors to be found. But they are not cheap.
 
If you've got a 240V, 3 phase motor already, a VFD, a bulletin 800t potentiometer, a Hoffman pushbutton box and some Sealtite would be all that you'd need to convert the machine. The existing forward/reverse controls could then be re-wired to provide control signals to the drive.

Note that multispeed motors have the disadvantages of increased size & weight (pain in the ass to install in a UMD) and drastically reduced power output when running at their lower speed(s). This means that the lower speed is only useful for comparatively light cuts.

Example: 1.5HP in high speed, 3/8 horsepower in low speed.

53776d1339718265-3-phase-2-speed-motor-wiring-need-help-photo.jpg
 
Yeah I get that VFD is probably easier, but I would like to keep the lathe more original. My goal was to increase the top speed to 1600 RPM and keep the lowest speed roughly the same as it is now (40 RPM) or slightly lower. I realize that in the low ranges I will only have 1 or 1.5 hp to work with, but I think that would be sufficient. The comment about installing it in the base is spot on, its a PITA even with a relatively small motor.
 
Careful overspeeding the bearings. Plain bearings don't take kindly to heat. The hotter they get, the more things expand. The more things expand, the hotter they get...

It's a positive feedback loop.
 
According to the catalogue a speed range up to 1600 RPM could be special ordered for the 13", I assume it was just a change in motor pulley size.
 
My 16" SB has 3 hp dual winding 2 speed and that is a beast of a motor in that machine. Maybe a 2 hp might be found small enough to fit. As I recall, my original 13" had a much smaller base cabinet underneath
 
A single speed motor operated with a VFD exactly imitates a two speed consequent pole motor. At half speed you get the same torque and half the hp, in both cases. A 240 volt drive with your existing motor will do what you want, I believe.
 
Nameplate seems weird. I would have expected the hp to halve with the rpm. i've been down the rabbit hole of trying to keep a three speed motor original and finally caved in and went the VFD route. If it were my decision, i'd look for a vector duty TENV 2 hp motor at 1200 rpm. Constant torque and smooth to 0 hz and torque and hp will hold up to about 90hz to cover any increased rpm you want to have. You can do the same with a standard inverter duty motor but the range is less.

I watch for Marathon Black or blue Max, Baldor IDNM, or Allen Bradley CM motors and sometimes you can find real deals. Dave
 
My 16" 2H came with a 2hp 2 speed motor and controls. Something of an indicator and safety bar on headstock belt cover. Not yet fully installed in this pic:

16.jpg

A rod fitting into that runs down the back of lathe to two drum switches. I dont have great pics of it, but the main rod controls a mechanism that switches both drum switches, for whichever position:


41.jpg 20.jpg

You could still make it happen without that mechanism, but you would need two drum switches all the same.

I use the low speed fairly often, including parting off. The last 16" I built, I looked for a 2-3 hp 2 speed for several months, all those I found were quite pricey compared to real nice regular 3 phase motors.

Plus one for not liking 1500rpm spindle speed on a South Bend. Most SB's natural top speed is around 900-1000rpm, and even then you're not in the top speed position all the time. Besides spindle speed, the whole gear train from left end through qcgb and apron are proportionally locked to that speed and sound un-natural and not good at spindle speeds over a 1000rpm. Even at a 1000rpm, I'm wide awake when all that gearing is engaged, and feeling a little itchy :D.
 
Don't lose those drum switches. The one is a standard fwd/off/rev one, but the other is highly specialized and operates to route the power to the correct windings for high/low operation of that motor. Most hardinge lathes, and the horizontal milling machines as well use that setup. The high/low switch has three sets of contacts for the high configuration, three sets for the low configuration, and two sets to short three wires for operation at one speed speed range.
 
jim rozen said:
Don't lose those drum switches. The one is a standard fwd/off/rev one, but the other is highly specialized and operates to route the power to the correct windings for high/low operation of that motor. Most hardinge lathes, and the horizontal milling machines as well use that setup. The high/low switch has three sets of contacts for the high configuration, three sets for the low configuration, and two sets to short three wires for operation at one speed speed range.
Click to expand...

Bugger if I can recall exactly, as its been several years since I've done the wiring. But I did make a drawing and/or wrote up the connections and shoved in a zip lock bag, which I put either in the motor's connection box, or one of the drum switch boxes.

However I don't think either of the drum switches is special. Possible exception being maybe one drum switch didn't have the soldiered wires cris-crossing for a rev.

Off a fuzzy memory, I want to say I have 6 hot wires going to motor for L1, L2, and L3. Three going to the normal higher rated speed for fwd and rev. The other 3 for the low speed, fwd only.

One drum switch operating as a normal drum switch is wired for 3 phase fwd and rev. The other drum switch only utilizing one output side, with the other side nothing connected.

The lever mechanism pretty clever, pinned levers that work together. Only one drum can turn "on" at a time, based on the timing of those levers, with the one drum switch able to cycle both fwd and rev.
 
I may have what you need Baldor motor 2 speed 213 frame. 2 hp. with drum switch. Came off of a Rockwell 14X40 metal lathe. But shipping would be a killer, you are pretty far away from me.
 
jim rozen said:
Don't lose those drum switches. The one is a standard fwd/off/rev one, but the other is highly specialized and operates to route the power to the correct windings for high/low operation of that motor.
Click to expand...
South Bend also used a Furnas JED4 drum switch for the dual winding 3PH. motors.
I've been trying to find one, but they're hard to find.

Doug
 

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