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RussZHC
02-12-2013, 07:23 AM
Leeson Gear Motor, 90VDC, 30:1 ratio, runs @ 60rpm, 56 lb-in torque.

I think the above has home made welding positioner written on it.

From what I gather, it is not the highest amount of torque (there seem to be lots with about double that) but there is at least one commercial model available that has exactly that.
From reading the rpm needs to be dropped quite a bit further, I was thinking of a belt drive (chain?) with a very large pulley having a large center hole so as to allow for tubing to be dropped through enabling flanges to be welded to pipe.

Knowing next to nothing about electrics, the first questions would be is the above motor appropriate? How complicated is it so as to eventually run off 115v and have control over varying the speed?
Aiming to have about 3rpm and lower final drive. Have to do a bit more reading but that 3rpm may end up being a bit high [bookmarked a lot of builds yesterday, have not had time to read fully and recall there was one with a speed chart on it (diameter v. rpm needed)]

Thoughts? Suggestions?

ShawnR
02-12-2013, 08:05 AM
Leeson Gear Motor, 90VDC, 30:1 ratio, runs @ 60rpm, 56 lb-in torque.

I think the above has home made welding positioner written on it.

From what I gather, it is not the highest amount of torque (there seem to be lots with about double that) but there is at least one commercial model available that has exactly that.
From reading the rpm needs to be dropped quite a bit further, I was thinking of a belt drive (chain?) with a very large pulley having a large center hole so as to allow for tubing to be dropped through enabling flanges to be welded to pipe.

Knowing next to nothing about electrics, the first questions would be is the above motor appropriate? How complicated is it so as to eventually run off 115v and have control over varying the speed?
Aiming to have about 3rpm and lower final drive. Have to do a bit more reading but that 3rpm may end up being a bit high [bookmarked a lot of builds yesterday, have not had time to read fully and recall there was one with a speed chart on it (diameter v. rpm needed)]

Thoughts? Suggestions?
If you are going to buy new, I would think you could find one with the RPM you want, or closer. You don't give any site references. Where are you buying it from? As for the DC aspect, you will need to come up with a power supply that can handle the current. Not a big deal, but one more thing you need to do. Then a motor controller if you want to vary speed. Don't use a rheostat, it should be what is called "Pulse Width Modulation" which essentially turns the power to the motor on and off rapidly, "pulses" The more frequently the pulses, the quicker the motor spins. If you visit a CNC site, there should be discussions on motor speed control. Getting the motor speed control in place, then you are just left with youe mechanics but you could burn up your nice new motor by not getting the right power supply/controller in place. I am not a motor control expert, just have a general electronics background. Perhaps someone with some CNC experience could chime in here. Having said that, I think my lathe has a DC motor on it, iirc.

Good luck

MaxHeadRoom
02-12-2013, 12:05 PM
Look on ebay for the KB or Baldor SCR 90VDC drives, You can even apply a foot pedal type that has a pot in it to vary the rpm on the pedal if you wish.
These connect directly to 120vac.
Max.

HAP
02-12-2013, 12:29 PM
Your best option would be an old or cheap pipe threader. You get massive torque and low rpm. Add a router speed controller and you are set. I'm sure you can find a suitalbe way to drive with it.

Pherdie
02-12-2013, 12:55 PM
Perhaps adapting this: http://www.harborfreight.com/portable-electric-pipe-threader-95955.html ???

MaxHeadRoom
02-12-2013, 12:58 PM
Leeson Gear Motor, 90VDC, 30:1 ratio, runs @ 60rpm, 56 lb-in torque.

I think the above has home made welding positioner written on it.

From what I gather, it is not the highest amount of torque (there seem to be lots with about double that) but there is at least one commercial model available that has exactly that Thoughts? Suggestions?

You don't need all that much to drive a welding table, you need to couple the G.B. output to the table somehow so just incorporate some reduction there and you should be OK.
Max.

nc5a
02-12-2013, 02:06 PM
Russ,

I made a welding turn table 35 years ago to buildup cross fire tubes for GE gas turbines. I used a small (1/10 HP) 120VAC right angle worm drive motor with a speed controller and a tig foot control for on/off. It had friction drive to turn a steel wheel 3/8"" thick and 12" in diameter. The 8" 3 jaw chuck that held the work piece was fixed to the 12" wheel and the motor and drive shaft were insulated from the wheel. Carbon brushes and holders from an exciter rode on the back side of the 12" wheel to allow current to flow through a rotating piece. The welder used the foot control to start and stop the rotation and the speed control to control rotational speed. The turn table is still in use.

Also, some windshield wiper motors and their controls make excellent fixture motors.

Ron

John Stevenson
02-12-2013, 03:27 PM
60 rpm is far too fast.
Read this thread.

http://bbs.homeshopmachinist.net/threads/33496

RussZHC
02-12-2013, 04:09 PM
Shawn: "scrounging" local Kijiji (think Canadian version of Craigs but with, IMO, usually a lot better photos), that particular Leeson has been languishing there for a few months now...the more direct route would be to find something on EBay, and I have, but the shipping for that sort of weight kills any sort of "deal" on the original cost. Said motor seems to be the most likely candidate so far. The hope would be to locate the heavy stuff locally and then get controllers and other small bits on EBay or elsewhere online.

HAP: had not thought of that...hmmm, reasonable shot too locally, perhaps better than finding a really low speed gear motor...am also considering nearly every other gear motor from wheelchair, to tread mill lifting motors (adjustable incline type tread mill), to garage door openers, to power seat motors, to slide out (trailers) motors, and on and on...one of the issues, and I could be very wrong here, that I see is some of those types of motors are not meant for "continuous" duty...just saying all but the wheelchair have relatively short working periods.

John: that happens to be one of the threads I did read...previous thought had been to "gear" down the 60rpm through a couple of pulleys, reducing as I go but I can see that getting complicated quickly (I do have some other gears that could make up some sort of more proper gear train though...) BUT there is also, locally, what I think could be an appropriate right angle gear box that has a 30:1 ratio, this would get it down to 2 rpm but from some of the numbers I recall, that is still not quite slow enough.

More reading and re-reading ahead.

Max: found several of the two makers you mention. Sort of assume the Baldor BC 138, BC 140 and BC 154 are not hugely different but sort of updated versions (higher numbers)? Found a couple of candidates from KB, their Camco "Vari-pak" and "Penta Drive". Those are/were complete boxes so to speak. There were a few that were more "just the boards" but there does not appear to be much gained once you start adding in given resistors, speed pots etc. Or that is the way I am viewing the offerings. Be gentle, I am definitely one of those plug it in and use it guys...I can do the work but definitely need help with understanding the dos and don'ts.

Thanks, all, Russ

RussZHC
02-12-2013, 04:17 PM
nc5a: not that the positioner you mention was but it amazes me sometimes of the longevity of a build that is "only temporary". Sort of also confirms what some reading has hinted at, that being which does what in terms of speed and on/off (which is foot and which is hand so to speak). The TIG foot control was something I knew about but had not thought of it in this context...another route to go.
Maybe I am not going at this quite right, perhaps I should just be looking at off the shelf parts for the guts and just build the box/frame...

Edit: any recall/thought as to how much the wheel plus 3 jaw weighed? Do you think there is any concern regarding weight or for that matter balance? From what I can recall there were some pretty amazing photos, guys "testing" by sitting on one and spinning around but also some quite long and heavy "arms" attached and then lifted (I mean to lift the end of maybe a 10 foot bar off the ground when the other end is bolted to the faceplate/wheel takes some "guts")

MaxHeadRoom
02-12-2013, 04:27 PM
Max: found several of the two makers you mention. Sort of assume the Baldor BC 138, BC 140 and BC 154 are not hugely different but sort of updated versions (higher numbers)? Found a couple of candidates from KB, their Camco "Vari-pak" and "Penta Drive". Those are/were complete boxes so to speak. There were a few that were more "just the boards" but there does not appear to be much gained once you start adding in given resistors, speed pots etc. Or that is the way I am viewing the offerings. Be gentle, I am definitely one of those plug it in and use it guys...I can do the work but definitely need help with understanding the dos and don'ts.

Thanks, all, Russ

The enclosure version gives you a reversing switch and pot, but generally if you use these externally you may as well buy the chassis version.
What part of Winnipeg are you in?
Dels Electric also sell them, also the plug in current resistor you need.
Max.

2ManyHobbies
02-12-2013, 04:29 PM
Find an old flywheel and a gear from a matching starter motor. I'm not absolutely certain, but that should be close to 20:1 and have a large center (which you could make really large if you needed).

RussZHC
02-12-2013, 04:49 PM
Max: as it happens, tomorrow is "day off", and there are way worse things to do than go to Dels...the local end of it was not something really delved into yet, who knows they may have all the bits and pieces around (also expect to try B+B Dynamo and Kings Electric), or maybe even an unclaimed gear motor with way lower rpm (I could not believe finding some that list fractions of a turn per minute) plus there are a few "scrap" places but those may have to wait until a bit less snow...

2ManyHobbies: glad you freshened the memory, with all the other thoughts...I was trying to think of a whole bunch of combinations of things that would have a ring and a gear to match without too much hassle...I had momentary visions of a ring gear of some sort under the table top...even an internal gear...thinking large diesel truck yards/parts...

nc5a
02-12-2013, 07:28 PM
Russ,

I'm not sure I clearly understood your reply to my post but if I led you down the garden path to a more complicated project than you were thinking of building I assure you it was not intentional. I presented my first hand experience at building a turn table to give you ideas not to suggest you build one like I did. The table I built was designed mainly to make it easier and faster to build up wear on 100's or maybe 1000"s of crossfire tubes during it's useful life. The crossfire tubes were about 2 1/2" in dia and 12" to 14" long and were made of stainless so weight was not a problem.

The welder used the foot control to start and stop the turn table when needed and the speed knob to set the speed of rotation. The 3 jaw chuck was an old cheap POS so no loss there. The whole thing was on a small roll a round cart.

Ron

CCWKen
02-12-2013, 10:33 PM
60rpm is damn fast welding! :)

RussZHC
02-13-2013, 12:36 AM
nc5a:
from time to time I am not sure of what I say or write either :rolleyes:..

Your build, clearly, was very functional as proved by the volume of work. I had not considered a worm drive but can see how it may have advantages.

Spent quite a bit more time over the past hours reading and watching a few videos. Designs similar to yours (chuck on a larger "plate") account for a goodly percentage of builds so its not a bad one to copy.



Three sort of groups.
A relative plain build with more or less specific repetitive tasks in mind in horizontal or vertical mode only. A more complex group that, in my mind, is more of a true "positioner" where one can adjust angles. Most of the time via a handwheel turning a gear cut in half though some are powered (some having a separate motor to drive a tilting mechanism like a jackscrew).
The other group is not really a group but there is a choice to be made between a solid center mounting a table or a chuck or a hollow tube center. I had started out thinking the hollow for passing longer pipe down it but have since found out the other advantage is you can purge the back of the weld area that way if needed.
As well a much smaller mixed group who use either hand or foot power for rotation or don't really use rotation at all but a series of arms that allow a given project to be done nearly entirely in horizontal position. In this group are those who use balls, hitch and bowling commonly, as sort of an elbow joint.

The other connecting point between many builds is discussion of the method of grounding and how using a hollow spindle can complicate the grounding a bit (seems to be largely "solved").

ShawnR
02-13-2013, 08:22 AM
Hey Russ

Here it is a little cheaper (lot cheaper) than what the seller states so maybe you can pick it up for a lot less than his asking price.....;-)

http://www.electricmotorwholesale.com/LEESON-M1125003/

and further on their site, you could put this controller on it and not have to worry about slowing it down at all. You would have a nice range of speed and maybe be able to use it for other options ie wood router, grinder, etc. by making the carriage kind of universal......Nice. :-)

http://www.electricmotorwholesale.com/9449-KBMM-125/

RussZHC
02-13-2013, 09:56 AM
Shawn:

thanks for the links...an earlier found link to Leeson did not work very well (left me sort of in a loop) so the info really helpful PLUS gives me a much better idea on prices and it looks like for a few bucks more I can purchase there (as example) rather than a bit of a hope and praying an EBay buy works as stated BONUS they ship internationally [about to go out door to visit a few local places, so now I can ask questions like I sort of know what I want ;)]

bborr01
02-13-2013, 10:15 AM
I have only skimmed through the responses here but have been thinking for a while about buiding a welding positioner. It seems like if you don't need to position huge out of balance items you could use a sewing machine motor and foot pedal. I am thinking that would give almost any speed one could want and form what I have read used ones are usually available fairly cheap at sewing machine repair places.

If the pulleys were situated at 90 degrees to one another, the belt could be quickly removed and re-installed to reverse the positioner. Just a thought.

Brian

RussZHC
02-13-2013, 08:52 PM
So today's little trip was useful.
Local shop opinion seemed to be the range of the controller is not a realistic 0% to 100% regardless of what the pot scale shows, more about 80% of the entire range (from actual motor rpm down). Controllers they have stock of many Baldor types but any of the gear motors are an ordering item. Got some prices on one with a bit more oomph (3x to 4x greater in lb) and lower rpm to start (somewhere around the 7 to 9 rpm range). Generally a bit more understanding of how things work...about what I expected in terms of price so not cheap.

The real bonus I guess was the local machinery supply is just down the block and they stock some Mitsubishi inserts of the size, style and coating I have been considering AND they will sell singles...meaning I don't have to buy quantity on EBay until I find one that works well for the situation (and even then the local prices are good enough that it may not be worth the hassle)

Rob Garner
02-13-2013, 11:17 PM
This is a direct replacement motor for the atlas brand positioner that I use at work.

http://www.grainger.com/Grainger/DAYTON-ACDC-Gearmotor-1LRA5?cm_sp=EN-_-L2-_-TopSellers&cm_vc=FFTS

Here is my home made positioner.

http://s159.photobucket.com/albums/t150/robg_010/welding%20positioner/

http://i159.photobucket.com/albums/t150/robg_010/welding%20positioner/S6303762Medium.jpg

http://i159.photobucket.com/albums/t150/robg_010/welding%20positioner/S6303744Medium.jpg

http://i159.photobucket.com/albums/t150/robg_010/welding%20positioner/S6303752Medium.jpg

RussZHC
02-14-2013, 12:19 AM
Rob: good photos, I am not quite back to the re-read of your build posted on another site. The link for the motor...same motor, more or less, here, is more than double the price the link gives which puts it in the ballpark between the two Baldor prices I was given this AM.

ShawnR
02-14-2013, 07:16 AM
Very nice job Rob! The detail even goes so far as to include the grounding of the chassis. Would probably easily pass CSA or ULC Standards. :-)

Willy
02-14-2013, 09:36 AM
Rob, I'm impressed!
Very professional, and thanks for the link to the rest of the build photos.

Funny, just before you posted your positioner build, I was looking for an rpm guide for welding positioners (I know simple math, but I'm lazy) when I ran into this one (http://www.fastenal.com/web/products/detail.ex?sku=0830467&ucst=t). Actually I think yours is probably better built.
What did you use for a grounding brush and holder?