Interesting day in the City:
- Thread starter Pete Wass
- Start date
Jim Wooten
Just Me
Pete,
Not having 3 phase was the primary reason that I went with the VFD. Since my Heavy 10 already had a 3 phase motor, and there was no easy way to get 3 phase power to the shop, I had to use a VFD or a rotary phase converter to supply the required power. The infinitely variable speed control with the VFD was icing on the cake.
I was told that 3 phase delivered "smoother" performance from the motor than a single phase motor as an additional benefit, but not being a machinist, I can't really comment on how much this affects the real life results. I was also told that 220 was preferable to 115 (more power. and easier to get a good surface finish with), but again, I am not an authority. Maybe Dave can jump in here and give us a more professional perspective (or any of the other experienced posters).
If I were buying a new motor, I think I would go with a single speed 3 phase of 1 to 1 1/2 hp, plus a VFD, but hey, what do I know
. If you do go this route, remember that you will need a VFD that is matched with the hp of your motor. I used a Hitachi SJ200 VFD, and it offers many options for programming the motor's performance, as well as a digital readout so that you can monitor a number of variables. Hopefully this is all irrelevant, and your motor is still all right.
Have you tried a serpentine belt to replace the standard belt yet? That really made a difference for my lathe. Less belt slippage on a heavy cut, and nice surface finishes with lighter cuts as well.
I also replaced the V belt that goes to the motor pulley with a Power Twist link-type V belt with good results. Seems that these old South Bends lend themselves to lots of tweaking and experimenting
.Jim
JerrySharrett
Senile Member
Mystery solved
Aha, now we know the cause of Pete's problem. He has been buying WalMart Communist Chinese made "creamery butter". Never, never, no, never put Wal Mart butter on the belts of a belt drive lathe. In a pinch you can use Land-O-Lakes butter with the heavy salt. Even Land-O-Lakes lightly salted will cause some slippage. I guess its the grit of the salt crystals??
Aha, now we know the cause of Pete's problem. He has been buying WalMart Communist Chinese made "creamery butter". Never, never, no, never put Wal Mart butter on the belts of a belt drive lathe. In a pinch you can use Land-O-Lakes butter with the heavy salt. Even Land-O-Lakes lightly salted will cause some slippage. I guess its the grit of the salt crystals??
S
ShadowChaser
Guest
Yes, for one thing, start up torque is much better in a 220/230 volt single phase motor as compared to a 115V single phase. the 220/230 motor is more efficient, less heating under heavy loads...
However the advise you are getting about putting a 3 phase motor on it is the best solution. Even though you do not have 3 phase where the lathe is located, 220 single phase to 3 phase conversion is very easy and you have the best of both worlds... VFD is one way or just using any old 3 phase motor as a rotary converter is simple enough and generates very good 3 phase power.
Happy shooting,
Mitch & Shadow...
Pete Wass
Well-known member
Appreciate all the help
Especially the tip on the Land o lakes. I must look for it nex time I go to a real Supermarket, which may be today. Probably would have thought to do this after having such a bad experirnce @ Wally World. Interesting to note that the Store Brand butter at the Hannaford store I usually use looks and tastes the same as the Land O Lakes, I sometimes buy when I'm feeling "Flush".
I was afraid there wouldn't be a simple solution to my lathe. The most simple may be to sell the dern thing and not be troubled with it. I could buy a Smithy and be done with all of this stress and wory, couldn't I?
I sure would like to be in the position to be able to set my barrels back on a regular basis and to do new crowns at about the same interval. Having the nice sized hole and relatively short length of the spindle on the ole SB seems like it's worth hanging on to that feature alone.
How much are we looking at for one of these 3 phase converters?
Especially the tip on the Land o lakes. I must look for it nex time I go to a real Supermarket, which may be today. Probably would have thought to do this after having such a bad experirnce @ Wally World
. Interesting to note that the Store Brand butter at the Hannaford store I usually use looks and tastes the same as the Land O Lakes, I sometimes buy when I'm feeling "Flush". I was afraid there wouldn't be a simple solution to my lathe. The most simple may be to sell the dern thing and not be troubled with it. I could buy a Smithy and be done with all of this stress and wory, couldn't I?
I sure would like to be in the position to be able to set my barrels back on a regular basis and to do new crowns at about the same interval. Having the nice sized hole and relatively short length of the spindle on the ole SB seems like it's worth hanging on to that feature alone.
How much are we looking at for one of these 3 phase converters?
JerrySharrett
Senile Member
Pete, if you are starting from scratch, buying a motor, VFD, etc, don't, just get a 220v single phase motor. Be aware the South Bend has a special bolt pattern but Granger did have them. You also need to make sure you have the correct shaft size.
Unless you really want to have variable speed going 3-ph and a VFD is more expensive and really useless for barrel work. I've done dozens of barrels and I only use 2 speeds, one for turning and the low gear (back gear) for chambering and threading. (470 rpm and 85 rpm)
Unless you really want to have variable speed going 3-ph and a VFD is more expensive and really useless for barrel work. I've done dozens of barrels and I only use 2 speeds, one for turning and the low gear (back gear) for chambering and threading. (470 rpm and 85 rpm)
S
ShadowChaser
Guest
Pete,
I have three 3 phase 220v machines in my shop. A 16" Southbend, a 13" Southbend, and a Series 1 Bridgeport with the variable speed drive head. Its been set up for so long, I'm not sure what size the motors are, I do know the Bridgeport is a 1 1/2" hp and is the smallest of the three.
I use an old 1940-1950's vintage cast iron framed 5hp 3 phase motor as a rotary phase converter. Why the 5hp motor? I had it available and no use for it with any of the machinery I presently operate due to its size and weight.
One thing it helps to realize about using a 3 phase motor as a converter is that 3 phase motors will run at normal operating speed (at reduced hp) on single phase power, the only issue is getting the 3 phase motor to start. When you add the second motor, the one on your machine tool, the two act together to generate the third leg. The second motor will operate normally both starting and reversing as it would on 3 phase power off the street.
Originally, when I first acquired a machine with a 3 phase motor on it, a 1 1/2 hp if my memory serves me correctly, I had a junk open frame real early 1/2hp 3 phase motor I used for a rotary converter initially and even though limited in size, it would run the larger motor fine in spite of being a bit light at supplying the start up current the larger motor required. The effect of this was that the large 3 phase motor took about 50% longer to get up to speed. Once it was at speed, it ran fine and seemed to develop full power.
I've since learned that the motor being used as the rotary converter should be equal in hp to the 3 phase motor in order to have heavy enough windings to supply the start up current required.
When I started adding machines to my shop, the old 1/2hp 3 phase acting as the converter was replaced with the 5hp I presently use and have been using for about 25 years now very satisfactorily.
Another benefit to using an old 3 phase motor as a converter, it only needs to be big enough to supply starting current for the largest motor in your shop. If you have multiple 3 phase motors running, each 3 phase motor enhances the operation of the rotary converter and contributes to the quality and capability of the 3 phase power being used. The more you run, the more you can run... Its a win-win situation.
The only drawback to using a 3 phase motor as a rotary converter is getting the converter motor to start on single phase power. Again, this can be as simple as you want it to be. My first rotary converter, I simply wrapped a cord around the shaft, gave it a pull to get the motor turning and threw the switch to put power to it and it would take right off spinning normally...
My present rotary converter, the 5 hp 3 phase motor, I have a small 3/4 hp 115 split phase motor on the same mount lined up with the shaft of the big motor. I use a pin clutch between the two and a lever to engage the clutch by sliding the small motor up to the big one. The lever has a momentary contact switch that turns on the power to the small motor when the clutch is engaged and this starts the big motor turning. Once the big motor starts to turn, I throw the 220V power switch and the big motor starts and at that point I pull back on the lever separating the motors as the small motor is no longer needed. The neat thing about this setup, the big motor only needs to be turning slowly, probably about 100 rpm and at that point it will start on its own when power is applied.
There have been times when I didn't use the "starter" motor such as having too much running on the 115v circuit its on and blew the 115v fuse, and at such times I have kicked the clutch of the 5hp motor with my foot to start the big motor turning slowly, then threw the 220v power switch and it takes off running just fine...
One caveat to this method, the direction of rotation of the converter motor determines the direction of rotation of the other 3 phase motors attached to it. You always want to start the converter motor turning in the same direction so that the other motors always run in the direction expected.
If you only have one other 3 phase motor wired into the circuit and its running backwards of what you need, simply restart the converter motor running in the opposite direction to get the right rotation of the tool motor. When you add other 3 phase motors in the shop, (and you will once you have one) then the direction of rotation of the converter motor always wants to be the same...
Reversing while tapping under power in a Bridgeport, piece of cake!!!
Happy shooting,
Mitch & Shadow...
Pete, an afterthought, is "Earl's Barter Barn" still in operation? As I recall, he's somewhere up near you, that might be a good place to find 3 phase motors...
I have three 3 phase 220v machines in my shop. A 16" Southbend, a 13" Southbend, and a Series 1 Bridgeport with the variable speed drive head. Its been set up for so long, I'm not sure what size the motors are, I do know the Bridgeport is a 1 1/2" hp and is the smallest of the three.
I use an old 1940-1950's vintage cast iron framed 5hp 3 phase motor as a rotary phase converter. Why the 5hp motor? I had it available and no use for it with any of the machinery I presently operate due to its size and weight.
One thing it helps to realize about using a 3 phase motor as a converter is that 3 phase motors will run at normal operating speed (at reduced hp) on single phase power, the only issue is getting the 3 phase motor to start. When you add the second motor, the one on your machine tool, the two act together to generate the third leg. The second motor will operate normally both starting and reversing as it would on 3 phase power off the street.
Originally, when I first acquired a machine with a 3 phase motor on it, a 1 1/2 hp if my memory serves me correctly, I had a junk open frame real early 1/2hp 3 phase motor I used for a rotary converter initially and even though limited in size, it would run the larger motor fine in spite of being a bit light at supplying the start up current the larger motor required. The effect of this was that the large 3 phase motor took about 50% longer to get up to speed. Once it was at speed, it ran fine and seemed to develop full power.
I've since learned that the motor being used as the rotary converter should be equal in hp to the 3 phase motor in order to have heavy enough windings to supply the start up current required.
When I started adding machines to my shop, the old 1/2hp 3 phase acting as the converter was replaced with the 5hp I presently use and have been using for about 25 years now very satisfactorily.
Another benefit to using an old 3 phase motor as a converter, it only needs to be big enough to supply starting current for the largest motor in your shop. If you have multiple 3 phase motors running, each 3 phase motor enhances the operation of the rotary converter and contributes to the quality and capability of the 3 phase power being used. The more you run, the more you can run... Its a win-win situation.
The only drawback to using a 3 phase motor as a rotary converter is getting the converter motor to start on single phase power. Again, this can be as simple as you want it to be. My first rotary converter, I simply wrapped a cord around the shaft, gave it a pull to get the motor turning and threw the switch to put power to it and it would take right off spinning normally...
My present rotary converter, the 5 hp 3 phase motor, I have a small 3/4 hp 115 split phase motor on the same mount lined up with the shaft of the big motor. I use a pin clutch between the two and a lever to engage the clutch by sliding the small motor up to the big one. The lever has a momentary contact switch that turns on the power to the small motor when the clutch is engaged and this starts the big motor turning. Once the big motor starts to turn, I throw the 220V power switch and the big motor starts and at that point I pull back on the lever separating the motors as the small motor is no longer needed. The neat thing about this setup, the big motor only needs to be turning slowly, probably about 100 rpm and at that point it will start on its own when power is applied.
There have been times when I didn't use the "starter" motor such as having too much running on the 115v circuit its on and blew the 115v fuse, and at such times I have kicked the clutch of the 5hp motor with my foot to start the big motor turning slowly, then threw the 220v power switch and it takes off running just fine...
One caveat to this method, the direction of rotation of the converter motor determines the direction of rotation of the other 3 phase motors attached to it. You always want to start the converter motor turning in the same direction so that the other motors always run in the direction expected.
If you only have one other 3 phase motor wired into the circuit and its running backwards of what you need, simply restart the converter motor running in the opposite direction to get the right rotation of the tool motor. When you add other 3 phase motors in the shop, (and you will once you have one) then the direction of rotation of the converter motor always wants to be the same...
Reversing while tapping under power in a Bridgeport, piece of cake!!!
Happy shooting,
Mitch & Shadow...
Pete, an afterthought, is "Earl's Barter Barn" still in operation? As I recall, he's somewhere up near you, that might be a good place to find 3 phase motors...
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