aux motor for SS

JPG · Post by **JPG** » Sun Oct 03, 2010 11:17 pm

prmindartmouth wrote:Well, I set up that aux. motor drive]10544[/ATTACH]
I used a McMillan Electric Model 2716 dc treadmill motor, 120v, 6 amp, fed by a rectifier hooked to a router speed control. The router speed control is good for up to 2hp routers so handles this load ok. I run it at near slowest setting and am not hearing any strange noises from the SS (yet?). The treadmill motor runs very smoothly. SS is left on slow and unplugged. Here is a closeup of the motor and rectifier:
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The motor base plate has a slot where the two thumb knobs are, to allow belt tensioning. There seems to be plenty of power with these pulleys. I am using a 3" and 10" pulley but want to get one smaller than the 3"when I can (or maybe bigger than the 10") to get even lower speed. I had to bore the 3" out on my metal lathe to suit the odd shaft diameter on the treadmill motor. At slowest speed it seems to be turning the SS at under 200rpm, a guess since I have not measured it yet.
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The big pulley had to go on the upper shaft. I used the base I made for the 7" grinder and drill sharpener and can easily reuse it for those again (see this post https://forum.shopsmith.com/viewtopic.php?t=5672 )
Here it is running.
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I want to use it first to polish the tubes off that old greenie I am slowly refurbing. Safety would suggest I should make some guards next.

I be curious why you have the speed control set to slow??? The ss motor loading would be much less if the ss was set to fast, and all the sheaves etc. would be rotating slower.

peterm · Post by **peterm** » Sun Oct 03, 2010 11:57 pm

Good question jpg and thank you for it. Reasons in favor of fast were well covered above, but I am mildly concerned about robinson's point about the centrifigal start switch if not rotated fast enough, plus I know I won't overspeed the SS motor since I intend to run at or below 200 rpm, which causes the SS motor to turn at 2/7 of normal, well within it's capability.
I did try running the speed control up to fast and back to slow while running the aux. motor and could not hear much difference in the noise made by the headstock.
In use as opposed to the test runs done so far, I will however likely leave the speed set somewhere in the middle. I think in reality, it does not matter one way or the other so long as the big pulley stays below 700 rpm.

JPG · Post by **JPG** » Mon Oct 04, 2010 2:05 pm

prmindartmouth wrote:Good question jpg and thank you for it. Reasons in favor of fast were well covered above, but I am mildly concerned about robinson's point about the centrifigal start switch if not rotated fast enough, plus I know I won't overspeed the SS motor since I intend to run at or below 200 rpm, which causes the SS motor to turn at 2/7 of normal, well within it's capability.
I did try running the speed control up to fast and back to slow while running the aux. motor and could not hear much difference in the noise made by the headstock.
In use as opposed to the test runs done so far, I will however likely leave the speed set somewhere in the middle. I think in reality, it does not matter one way or the other so long as the big pulley stays below 700 rpm.

FWIW, the condition of the 'start switch' is irrelevant in this setup(I am assuming you do not intend to 'start' the 'normal' motor while using this external motor setup:D:eek:).

The mechanical load of the 'extra' innards will be less if set to high speed.

No sense in increasing the wear and tear more than necessary.

BTW a 8" pulley will fit on the aux shaft and that would be the equivalent of a 12+" pulley on the top shaft, and, would be much easier to enclose.

Your setup reminds me of the thread on the planer feed motor speed control!

Wunnerul idea!

Ya might try attaching a capacitor across the motor terminals(at least 150v rating). Might smooth it out a bit. Beware of increased energy hazard potential(pun intended, but hazard is real).

peterm · Post by **peterm** » Mon Oct 04, 2010 6:09 pm

jpg, thank you for the comment about the 8" pulley. I got one today and installed it on the idler shaft. I also put a 2" on the aux. dc motor. I had to insert a spacer block under the motor to get belt clearance, belt clears the top shaft hub by 1/4" and the way tube by half that. Makes that hub available too.
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This setup is much better. I am going to get a lighter belt, this one is a bit too stiff and I want to pretty up that wood spacer block. This setup runs very smoothly and the slow speed is now 160rpm, got by counting revs for 15sec. VERY nice. Will be easy to guard as you said.
Thanks again!

JPG · Post by **JPG** » Mon Oct 04, 2010 11:21 pm

prmindartmouth wrote: . . .
I am going to get a lighter belt, this one is a bit too stiff and I want to pretty up that wood spacer block. . . .

A 'segmented' belt would be less 'stiff'.

robinson46176 · Post by **robinson46176** » Tue Oct 05, 2010 7:35 am

JPG40504 wrote:FWIW, the condition of the 'start switch' is irrelevant in this setup(I am assuming you do not intend to 'start' the 'normal' motor while using this external motor setup:D:eek:).

I'm afraid that that statement is incorrect and that you missed my point...
My concern has nothing to do with current at all. Flip on any motor that uses a centrifugal start switch then flip it back off. Do you hear that switch drop back into contact as it slows down? Do you hear the centrifugal mechanism dragging until the motor comes to a complete stop. That switch activation mechanism is NOT designed to be dragging full time. If you run it that way it WILL wear out that mechanism quite quickly. It is only designed to be in that physical contact position for a few seconds at start up and at shut down (and while the motor is not turning). If his "normal" motor is spinning fast enough to kick the start switch he is OK. If it sits and spins too slowly to kick that switch regardless of power to that motor or not, that centrifugal mechanism will not hold up for long run times. It becomes a constant mechanical wear point.

dusty · Post by **dusty** » Tue Oct 05, 2010 7:58 am

robinson46176 wrote:I'm afraid that that statement is incorrect and that you missed my point...
My concern has nothing to do with current at all. Flip on any motor that uses a centrifugal start switch then flip it back off. Do you hear that switch drop back into contact as it slows down? Do you hear the centrifugal mechanism dragging until the motor comes to a complete stop. That switch activation mechanism is NOT designed to be dragging full time. If you run it that way it WILL wear out that mechanism quite quickly. It is only designed to be in that physical contact position for a few seconds at start up and at shut down (and while the motor is not turning). If his "normal" motor is spinning fast enough to kick the start switch he is OK. If it sits and spins too slowly to kick that switch regardless of power to that motor or not, that centrifugal mechanism will not hold up for long run times. It becomes a constant mechanical wear point.

You can determine the approximate speed at which the centrifugal switch activates/deactivates by spinning the shaft using a drill motor attached to the drive shaft. It is not as slow as you might think - which makes farmer's point.

What am I thinking. Peter does not have to use a drill motor. He already has an external drive source.

JPG · Post by **JPG** » Tue Oct 05, 2010 11:54 am

robinson46176 wrote:I'm afraid that that statement is incorrect and that you missed my point...
My concern has nothing to do with current at all. Flip on any motor that uses a centrifugal start switch then flip it back off. Do you hear that switch drop back into contact as it slows down? Do you hear the centrifugal mechanism dragging until the motor comes to a complete stop. That switch activation mechanism is NOT designed to be dragging full time. If you run it that way it WILL wear out that mechanism quite quickly. It is only designed to be in that physical contact position for a few seconds at start up and at shut down (and while the motor is not turning). If his "normal" motor is spinning fast enough to kick the start switch he is OK. If it sits and spins too slowly to kick that switch regardless of power to that motor or not, that centrifugal mechanism will not hold up for long run times. It becomes a constant mechanical wear point.

Point well taken!

Actual actuator design dependent.

Doubt that would be a significant wear problem with older emerson motors. Other motors - could be!

curtis george · Post by **curtis george** » Fri Oct 08, 2010 6:58 am

Hello
Why dont you just make your own speed reducer ? by hooking up pullieys and belts to the head stock.

I would think a block of wood mounted to the rails, with two bearings (or bushings) with four pullieys on it. large to small, and then small to large. I have not done the math, but something like a 4x1 ratio should do.
I hope this makes since. Im at work now (that is Im not on the books yet, but I am at work) so I cant pull up any info. but I would suggest to look at any old lathe book on reduceing speed. I would not think that it would be all that hard to make a speed reducer.

Good luck.

C.A.G.

billmayo · Post by **billmayo** » Fri Oct 08, 2010 8:19 am

curtisgeorge wrote:Hello
Why dont you just make your own speed reducer ? by hooking up pullieys and belts to the head stock.

I would think a block of wood mounted to the rails, with two bearings (or bushings) with four pullieys on it. large to small, and then small to large. I have not done the math, but something like a 4x1 ratio should do.
I hope this makes since. Im at work now (that is Im not on the books yet, but I am at work) so I cant pull up any info. but I would suggest to look at any old lathe book on reduceing speed. I would not think that it would be all that hard to make a speed reducer.

Good luck.

C.A.G.

See Post 5 at https://forum.shopsmith.com/viewtopic.php?t=6499 for my comments on the above topic. No aux. shaft with pulleys is needed as I was able to get around a 4:1 reduction or increase depending on location of the pulleys. I found the Gilmer headstock without a Gilmer belt works really well for this setup.