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9 inch Southbend Motor upgrade
- Thread starter sasanifab
- Start date
- Replies 24
- Views 3,965
thermite
Diamond
- Joined
- Sep 21, 2011
Why f**k around?
1,000 HP per inch of swing, and a QCTP, everybody knows it will make yer dick get fatter and longer!
9000 HP, 900 RPM, GE, FRAME 8913, SBWPI, 2300/4160/6600V | East Coast Electrical Motor Inventory
3/4 HP is all the drivetrain can stand at full load, BTW. 1 to 1.5 HP ONLY if you are going to VFD it and need the reserve at very low RPM.
Any greater, best to not try to make full USE of it! Compound comes off the topslide of the cross too readily.
It's a South Bend. 1/2 HP was plenty. SB knew their lathes.
Not a Craven:
biggest lathes craven brothers manchester - YouTube
thermite
Diamond
- Joined
- Sep 21, 2011
Hell no! Something is amiss. You don't need a larger motor. You just need a healthier 1/2 HP.
The OEM 3/4 HP, late 1950's - early 1960's on the SB ten would smartly "chirp" the belts at start or instantaneous reverse.
If your motor turns freely by hand, unpowered, you may have lost a phase.
If it does not, it may be packed up with degraded grease or have a bad bearing.
What is your source for three-phase power?
Static converter with one or more capacitors gone bad, mayhap?
the lathe came with a box for phase conversion, it looks old. The motor is hard wired into the box. Im starting to wonder if this is my problem. If I have the belt on the fastest setting it wont start moving until I spin the chuck. The motor spins freely. This lathe was taken care of very well.
Yes sir , its a "phaseamatic"
thermite
Diamond
- Joined
- Sep 21, 2011
I'm not sure those are legally acceptable in the landfill. Might need HAZMAT or ROHS disposal?
But you need something "real", even for 1/2 HP and those 'static" converters that do not actually convert are snake oil, even brand-new.
Weg (Brazil) and several others have small VFD that can output 230 VAC 3-Phase off 120 VAC single-phase WHEN run at 1 HP or lesser loads.
Same units are good for two HP if run off 240 VAC single-phase.
An RPC only make sense if you will have at least one other 3-Phase load, preferably two or more others.
OTOH, you only need a(ny) half-decent 1 to 3 HP 3-Phase motor, your 240 VAC feed, and not a great deal else to DIY an RPC.
SB has enough monkey-motion in the drivetrain it isn't all that pickey and will run OK off a single-phase motor, so long as you don't need rapid reversing - better-yet, don't need reversing at all!
4GSR
Diamond
- Joined
- Jan 25, 2005
- Location
- Victoria, Texas, USA
The old 1/4 HP 1-phase motor that was on my 9" SBL was like that for over thirty years. One day, I pulled the motor and replaced it with a 1/2 HP DC PM Motor. Talking about nice! Lots of turning power at most RPM's.
Ken
johansen
Stainless
- Joined
- Aug 16, 2014
- Location
- silverdale wa
1/3rd hp is the limit for the cast iron bull gear at slowest speed of 40 rpm.
Other than that you could use a larger motor, but my guess is your starting system has failed or the motor is wired for 440vac
Other than that you could use a larger motor, but my guess is your starting system has failed or the motor is wired for 440vac
thermite
Diamond
- Joined
- Sep 21, 2011
3/4 HP was on the "toolroom" ten. Per SB guru's (I am not one), it could trash your SB 9.
You will be HAPPY once you get a "true" 1/2 HP!
A Phase-a-matic would have been running it at about 1/6 HP even before it failed.
Dee Cee? Yah. Can do. Any shunt-wound 90 VDC (for 120 VAC outlet) or 180 VDC (for 240 VAC outlet) motor, even PM. KB-Penta or similar DC drive from Minarik, Dart, Danfoss-Graham, etc.
Have a care. DC motors are torque animals right down to "locked rotor". Back gears can die.
Weg 7518OS1BD56 3/4HP AC Motor (SSM) | eBay If I wanted to fit something like this ....would it work
thermite
Diamond
- Joined
- Sep 21, 2011
You do not yet know if you NEED another MOTOR.
It has been starving on the fake-teat of a POS Phase-a-Matic!!!
Motor you have could be just fine if given a decent source of power.
It has been starving on the fake-teat of a POS Phase-a-Matic!!!
Motor you have could be just fine if given a decent source of power.
I’m confident the motor is ok, the more I read into phase converting the more I realize that without a really good vfd I’m not getting the full potential of the 3 phase motor. So my options are an expensive vfd or replace the motor with a single phase 240volt motor. Which will probably end up being cheaper? Either way it def feels like I’m.only getting a 1/3 maybe less of the motors potential with the fakeomatic
thermite
Diamond
- Joined
- Sep 21, 2011
Theoretical figure is 31%.. IF.. I recall correctly. RPC is 91% IIRC. Phase-Perfect or mains 3-P is 100%.
VFD can be OVER 100%.
Single-phase is ALWAYS a pain to reverse, NEVER quite as smooth as 3-P, but, but, but... it's not easy to notice after going through two or more stages of belt drive.
What you WILL notice is having a full half-horse instead of only a third of it.
thermite
Diamond
- Joined
- Sep 21, 2011
They make good ones.
But try this search first:
rotary phase converter
Then lowest cost first.
Even with a control kit, you will still need to find a motor for an idler.
Note also that PM has stickies in the Phase Converter and VFD Forum to build all types.
Realistically, anywhere from $50 with a free/salvaged motor to about $250 for your modest needs.
