Low bucks motorized grain mill

[augiedoggy]

Spellman, sorry the setup isn't working right, I probably should have waiting to run a full batch of grain before posting. Did you start with a full hopper? My test run was only a pound of grain which only filled the hopper maybe a fourth of the way up; I guess I need to try a full hopper myself.

As far as the motor reversing by itself when it jams ( if I'm reading that correctly ) I believe that is probably normal; I read one post where a guy hooked one of these motors up with no start capacitor and it still ran but it would randomly choose which direction to start turning in, this leads me to believe that if you prevent it turning one direction it will go the other direction regardless of which side of the cap it's getting power from, I think this applies to all reversible gear motors not just this particular one.

If you want to try an experiment you could wire up 2 of the caps you received in parallel which would be the equivalent of a 10MFD cap. I've read that you can "hotrod" a AC gear motor this way to generate more torque ( it won't run any faster however ), the down side is the motor will run hot and it will shorten the life of the motor dramatically. However since the milling process time is relatively short it might be possible to get several runs out of it before the motor croaked. At $27 buck each you could go through 4 or 5 cheap motors and still come out cheaper than buying a $180 motor. It's just a thought and if you were to try that experiment I wouldn't wander too far away from the power switch when you start it up!:cross:

Here's a wiring diagram showing a 2.5MFD cap added for more torque wired in through a second switch for a total of 7.5MFD, the second switch could be used to cut in the extra capacitance when the motor starts bogging down.

Augiedoggy, yeah that's the great thing about Lovejoy couplings, pretty much impossible to jump gears.

I had service call on a UV flatbed printer about a month ago were one of those couplers failed and took out 6k in printheads.. .. I'm very familiar with them and in this type of application they should work very well but my issue is that my motor is also only 60 rpm and this was too slow to reliably grind without causing the gears to jump and bind.
I have since bought pulleys at tractor supply and as soon as I am home this weekend I will have everything together to test out.
Fyi it was plastic gears from the Xerox machine I was using on the motor and mill shaft...
Funny thing Is I have a whole box of those capacitors... I wanted to buy two for my old metal halide salt water reef tank lights a few years back and the seller ended up sending me a whole box of like 20 of them.... been finding all sorts of uses for them

 

[Spellman]

well funny story... in my haste to throw the electrical together last week I overlooked one crucial factor. The three caps that they sent me were not 440v 5 mfd as I had thought, they were 440v 1.5 mfd. Might explain a lot. I hooked them all up in a series and was able to run 3# 2-row and 3# of white wheat through with ease. I did start the motor first as I was a little gun-shy this time. I did go ahead and order the correct switch that I needed and a 5 mfd cap as I would rather hide one than the entire ghostbuster pack that I have now. Next time I'll try it out with a full hopper and report back, but my guess is it will work just fine! Thanks for all the help!

 

[J_Hanna]

Spellman, well I guess 3 x 1.5 is pretty close to 5
It would have been nice of them to have dropped a note in the box, oh well at least you got some kind of caps to go with your motor instead of the zero that came with mine.
You mentioned hooking them up in series, I'm not trying to be a know-it-all but the total capacitance of capacitors hooked up in series is not the sum of all 3 added together; in fact it will be less than just 1 by itself ( if I'm remembering correctly what they taught me at the tech school I attended about 40 years ago at Keesler Air Force Base in beautiful Biloxi Mississippi ). To get your 4.5 mfd I believe you need to hook them up in parallel. Cheers!

 

[Spellman]

You are correct, I misspoke and actually have them in parallel, can't sneak nothing past you!

 

[Spellman]

I was finally getting the motor screwed down to my still temporary board today and noticed something about the start of the motor. If it has drained caps it takes a second to "power up" when you start and stutters just a bit. But if the cap is charged it spins immediately. I think I may wire the switch when it gets here after the cap instead of before, that way it is juiced up before I start it, which may help if starting with a full hopper. Anyone see any problem with this? This won't be plugged in all the time so I don't anticipate there being any problem with it having a charged cap when not in use. Going to put 24 lbs through this little guy tomorrow.

 

[mattd2]

I was finally getting the motor screwed down to my still temporary board today and noticed something about the start of the motor. If it has drained caps it takes a second to "power up" when you start and stutters just a bit. But if the cap is charged it spins immediately. I think I may wire the switch when it gets here after the cap instead of before, that way it is juiced up before I start it, which may help if starting with a full hopper. Anyone see any problem with this? This won't be plugged in all the time so I don't anticipate there being any problem with it having a charged cap when not in use. Going to put 24 lbs through this little guy tomorrow.

This is awesome guys! It has been great watching and seeing what my previous understanding on minimum power requirements get destroyed.
Doing a quick bit of back of ciggy packet maths and some big assumptions it would seem that the critical figure is the ~10 lbf. in. of torque. I suppose running it faster (and therefore needing more power) will help it power through bits of hard grain, etc. due to the angular momentum of the rollers/motor but is not 100% necessary.
My quick maths based on the same overall efficiency (10% input power -> output power which seems low?????) a 1/3hp motor running at 200 RPM give... ~10 lbf. in. of torque!

 

[J_Hanna]

I was finally getting the motor screwed down to my still temporary board today and noticed something about the start of the motor. If it has drained caps it takes a second to "power up" when you start and stutters just a bit. But if the cap is charged it spins immediately. I think I may wire the switch when it gets here after the cap instead of before, that way it is juiced up before I start it, which may help if starting with a full hopper. Anyone see any problem with this? This won't be plugged in all the time so I don't anticipate there being any problem with it having a charged cap when not in use. Going to put 24 lbs through this little guy tomorrow.

Spellman,
Interesting! I'd think you'd need 2 switches to make it work, the original SPDT needed to switch between forward/off/reverse ( placed before the cap ) and a DPST ( after the cap ) to control the output from the cap to the motor. Cheers!

 

[Spellman]

Yeah the more I thought about it I was wondering the same thing. I did my smoked porter thursday and did 24 lbs of grain with no problems. Had it do a cold start with full hoppers twice, went right through it with ease. It did take a while to go through that much grain, I think it was 20-25 min of grinding. I'll try and keep a better time clock next time. Yeah that is a while, but takes much longer than that to get my water up to temp, so I don't really care that much. I would say for simplicity, compactness, and price, these things are hard to beat!

 

[J_Hanna]

Spellman, I am so happy that it worked this time!
It might be another month or so before I use mine as I am currently building a 3 tier gravity fed brewstand for my AG setup, I've got most of the steel I need, just need to cut all the pieces and start welding. I bought a new 220V stick welder for this project and had to wire in a new heavy duty circuit in the work shop to feed it; that slowed me down some but hopefully I'm back on track.
I'll take pictures as I go along on the brewstand, cheers!

 

[Spellman]

Sounds like a fun project! I built an eherms setup last fall with some of PJ's diagrams and I love having a big boy setup. If you haven't thought about going electric, you should! They can be pricey to get all the bells and whistles at first, but I have ultimate surgical precision when brewing now!

 

[J_Hanna]

Even though the AC gearmotor works great I started thinking about that DC gearmotor I found at American Science and Surplus and wondered if I could make it work for this application.

http://www.sciplus.com/p/CAR-SEAT-312VDC-GEAR-MOTOR_49248

MOTOR, 12VDC GEAR W/R.A. WORM DRIVE, 190RPM (BP) $14.75 plus 5.95 S&H ( $20.70 total )

I knew that it's original purpose was to move car seats back and forth so even though I didn't have a torque rating for it I knew that it must be pretty stout to move a car seat with your average adult american sitting in it. The 190 RPM speed would be a improvement as well.

The other pieces of hardware needed would be a DC motor controller board of some kind, mounting bracket, wires, spade connectors, another Lovejoy coupler and a 12V power supply.

Rooting around in my junk box I found a 3.3A 12V power supply, similar ones on Amazon sell for around $10. The motor is rated to stall at 25A so I was a liitle concerned that 3.3A would not be enough power but I can now report that this is plenty, more on this later.

If you don't have one laying around here's a 6A 12V power supply from Amazon...

http://www.amazon.com/dp/B003TUMDWG/?tag=skimlinks_replacement-20

6a Adapter Power Supply for LCD Monitor with Power Cord ($6.60 plus ? S&H )

Since this is a reversible motor I knew I needed a motor controller that could switch polarity, on Amazon I found this DC motor controller...

http://www.amazon.com/dp/B00EQ1UQXU/?tag=skimlinks_replacement-20

Generic Reversible 6V-30V 6A Pulse Width PWM DC Motor Speed Controller Governor $10.69 w/free shipping ( from China, took less than 9 days to get here. )

This controller is rated for 12V 10A max which seems to be plenty. It comes with a forward/off/reverse switch and a speed control pot, nifty!



Once I had all the parts in hand the first thing I did was make all the electrical connections and verify that everything worked. The power connector on the motor is/was some kind of unique plug design, the kind that you'll never find the correct corresponding wire harness to fit it. The work around on that was to carefully cut away the outer shell of the connector which exposed 2 standard sized spade connectors.



All wired up everything worked as advertised.

Next, as a safety precaution, I decided to put the motor controller board in an enclosure, anything bigger than the board itself would work fine. I found a clear plastic box that an Ipod had come in that was just about perfect, a little whittling and a couple of zip-ties later and it's good to go. Since the box is clear I get to see the LEDs light up and look at the components, cheap thrills.



For the purpose of setup I mounted the motor to a scrap board using a Stanley L-bracket I had laying around, I think it was about a 2.5" or maybe 3" bracket. I had to drill a new mounting hole in the bracket to raise the motor up a little, I then cut off the unused portion of the top part of the bracket just for looks.





Next I took an angle grinder and cut off all but about 1.5 inches of the shaft. I placed another scrap board under the shaft while cutting to keep unnecessary pressure off the shaft.





The closest size Lovejoy coupler was an L050 with a .438" bore, to make it fit I had to file down the shaft. To do this, with the motor still connected to the scrap board and clamped down on the workbench, I turned the motor on and used the motor itself as a lathe.



As I was milling away the excess shaft material it was necessary for me to bear down pretty hard with the file and I can report that at no point did the motor act like it was going to stall. The motor did get a little warm but only after I had spent like 10 minutes bearing down on the shaft; this tells me that I have more that enough torque and that 3.3A should be plenty of power.



Here's a photo of the DC motor next to the AC motor, at this point I don't plan on changing motors but I'm pretty confident that the DC motor setup would work fine if I did.



I put around $40 into this experiment and had at least twice that dollar amount of fun playing with it.

 

[mattd2]

You can't stop there! Please at least give it a test run. This has been an awesome thread, thanks!

 

[Stealthcruiser]

Yup, waitin' on a test run!
Anxious to see how that motor will "fare" with running a good bit longer than a seat adjust!

 

[Spellman]

Thanks for this, just when I was starting to feel content with my motor... I went ahead and ordered one of these. This appears to be everything I would want to change on my already well working mill, even more compact and a more appropriate speed. I'm going to initially try it without a switch for the polarity and see how well that works, as I already have everything else but that and the different coupler size. Do you think a 12mm bore would fit the shaft? If this works well I may have to finally build a proper station for the mill! This thread keeps getting better and better!

 

[J_Hanna]

Spellman, don't let yourself be dragged into my madness, get out while you still can!!!

Stealthcruiser and mattd2, I'm steadily working on getting my AG setup going but I'm still at least a month away from needing any grain crushed. I'm still working on welding up my 3 tier brewstand and I haven't even ordered my new brew pots yet ( although I do have some b*tching 3 piece ball valves with quick disconnects waiting on my desk ). I can't decide if I want 10 gallon or 15 gallon pots.
But honestly I think the DC gearmotor will work fine, I was seriously bearing down hard on the shaft with a file for at least 10 minutes and the motor never even slowed down. That being said I will go ahead and hook the DC motor up to the mill and use that motor for the first real grain crush, hopefully in a month or so. Cheers!

 

[Spellman]

Definitely go at least 15. Mine are 17 and I do a lot of 10g batches, with all of my calculations with loss, boil off, cooling shrinkage, and so on I need 13.5 initial boil volume to get me 11 in the fermentor, to get me 5 in each keg. With the 15 you will still be able to do a 5g batch just fine. And yeah, for $20 you bet your @ss i'm going to give it a go! With everything I have found on the net and in another thread:

"I was once told by a brewery designer that the magic number is 15 inches per second face roller speed. Figuring a 1.5 inch roller would be 4.5 inches circumference, that would be 3 rotations per second, being 180 rpm as ideal speed for the roller." -ImaBrewinfool

This seemed to make great sense and is pretty close to other information I have found. The cereal killer has 1.25" rollers which factors out to be about 230rpm, which this gets me right in the wheel house. If this works well, I'm pretty sure I would have no trouble selling the first one to a friend...unless they see the new one that could be had for $20. Damn. If that is the case my only option is to buy another mill for the spare motor and brew twice as often!

 

[mattd2]

Definitely go at least 15. Mine are 17 and I do a lot of 10g batches, with all of my calculations with loss, boil off, cooling shrinkage, and so on I need 13.5 initial boil volume to get me 11 in the fermentor, to get me 5 in each keg. With the 15 you will still be able to do a 5g batch just fine. And yeah, for $20 you bet your @ss i'm going to give it a go! With everything I have found on the net and in another thread:

"I was once told by a brewery designer that the magic number is 15 inches per second face roller speed. Figuring a 1.5 inch roller would be 4.5 inches circumference, that would be 3 rotations per second, being 180 rpm as ideal speed for the roller." -ImaBrewinfool

This seemed to make great sense and is pretty close to other information I have found. The cereal killer has 1.25" rollers which factors out to be about 230rpm, which this gets me right in the wheel house. If this works well, I'm pretty sure I would have no trouble selling the first one to a friend...unless they see the new one that could be had for $20. Damn. If that is the case my only option is to buy another mill for the spare motor and brew twice as often!

Agree with the pot size - what's the difference in cost between the 2?

1 month isn't long to wait - good luck on you build

 

[rekoob]

You guys are awesome. I am looking forward to hearing how that DC motor works out.

I'm a little tight on the brew funds right at the moment but I think this project or something very close just went to the top of my "things I want to do" list.

I currently have a Corrona mill that I turn with a large drill... I'm thinking it now need a dedicated motor drive...

I will keep a close eye on this thread so I don't miss a thing.

Thanks again for all the info.

 

[Spellman]

A couple things, I'm trying to get the dc motor up and running, and trying to compile how much torque we are getting on these motors.

1. With the dc motor hooked straight up it to a power supply doesn't want to turn. It kind of strobes and makes half turns. I tried hooking it up to a pwm I had in my stir plate and it doesn't want to turn much either until I spin the dial, then it seems to catch its breath and operate normally. I'm guessing this goes back to needing some sort of start capacitor? The pwm has some caps built in and I'm guessing when I spin the dial it allows them to charge up and operate correctly. I should note that I have the switch wired before adapter on that so that if I shut the switch off it powers down the adapter as well and isn't on all the time. Would it be possible to use some of my other caps in front of this motor? I don't exactly know how the voltage works on those, if I am only supplying it with 12v will it only put that out?

2. I believe the larger ac motor is mislabeled 10 lbs/in torque. If my calculations are correct it is more like 53 lbs/in. Everything I could find on adequate torque for a mill suggested that 30-40 is minimum. From what I read 10 probably would have little to no chance at working, which would support the fact it may be a higher number. I know it isn't exact science, but I saw a motor on ebay that looked almost exactly the same as these, but I think it was a different brand. It had almost the same specs for power consumption and rpm, and I think they said it was like 60 lbs/in torque or something. Sorry no link to that as I saw it on my phone and don't remember what I searched for, all I remember is it was used for a hospital bed.

I'll put up all the equations and calculations I have been using so that someone smarter than me can look them over in another long winded post when I get a chance. Work has been crazy busy!

 

[MerlinWerks]

Decided to give the DC motor setup a whirl
Got the motor and power supply waiting on the controller. Have a 1/2" lovejoy on hand but it is too big. Where did you get the lovejoy with the .438" bore?

 

[J_Hanna]

MerlinWerks, that was an Amazon purchase...

http://www.amazon.com/gp/product/B003HIWNZC/?tag=skimlinks_replacement-20

If there were a coupler between .438 and .5 it might be worth a try, didn't see one on Amazon. Oh well, the .438 works fine after milling the shaft a bit, cheers!

 

[J_Hanna]

Spellman, my memory on DC motors is a bit fuzzy but I think the deal is that the controller is needed to send pulses of current to the motor, something about a sawtooth wave form? All I know for sure is that cheapy controller I bought works great.
BTW, I decided on 15 gallon pots; they should be arriving early next week. I did have to adjust my brew stand design a little for the bigger pots but the pieces of steel I've cut already will still work I believe, hopefully I can start welding this weekend!

 

[chainlife]

Subscribed! Great thread and will post pics when i get into it this winter!!

 

[Spellman]

That's great news! I'm sure you will not regret the bigger pots! I had thought more about using some of those caps I had and I decided not to try them. I don't think they would damage the motor, but would also not have much effect on them. I think the "strobing" was because dc motors have a lot of inrush that they need to start the motor turning. I was looking up some tips on wiring power seat motors and it looks like they need about 5-7 amps when they move with a person in the seat, and spike up towards 15a when the seat reaches the end of the movement path (forcing it to max out and stall). I'm guessing the 5a supply I was testing with didn't have enough poop in the pants to get it going properly, as there is probably a high spike in amps initially to get it moving. The led of the power supply would blink with the motor pulses. I'm guessing the capacitors on these pwm's helps relieve this inrush and allows it to start moving. When used in a car they don't have one of these attached, but they also have access to 25a from the battery. Essentially the pwm is a cheap and easy work around for this. My pwm didn't have the switch (and I don't think it was a very high amperage one either), and I'm guessing that the caps would charge before activating the motor by the switch. Bottom line I have one on order!

On another note I think my 12mm coupler should be arriving today and I will report back how well it fits. This thread is super awesome as I haven't seen much information on using smaller motors such as these, and I love getting things documented for future use!

 

[fsr_racer]

Subscribed.

 

[MerlinWerks]

Hooked everything up last night and it was a no-go. I don't think 6A is enough. Had about 4 lbs. in the hopper and it wouldn't budge. I'm going to try an old PC ATX PSU to see if a little more oompf will help. Will also try starting without a loaded hopper to see if that makes a difference.

FWIW, I ended up boring out the coupler rather than milling down the shaft to get things to fit.

 

[Spellman]

Got my 12mm coupler yesterday which fits very well. The pwm also came in and i still have the same issues with it pulsing which cease after i slow the speed down and raise back up. I'd have to look back at my notes, but i think 10a should give more of the torque we need. I have an old computer supply as well that i may try using, but it won't be for a week or two that i can get that going. I'm still confident we can get this motor up and running for what we need.

 

[J_Hanna]

Hooked everything up last night and it was a no-go. I don't think 6A is enough. Had about 4 lbs. in the hopper and it wouldn't budge. I'm going to try an old PC ATX PSU to see if a little more oompf will help. Will also try starting without a loaded hopper to see if that makes a difference.

FWIW, I ended up boring out the coupler rather than milling down the shaft to get things to fit.

MerlinWerks, I'm bummed that you're having problems with this...
The motor and mill turns okay with no grain in the hopper? No binding at the coupler at all? My 3A power supply seems to be plenty, I don't understand it. Are you using the same controller board I have on mine? I wasn't getting much out of mine until I cranked up the speed control potentiometer over halfway. Let me know how it does with starting with an empty hopper.

I will mount my motor this weekend and make a couple of trial runs, I would have done that before now but I've been busy working on the brewstand, lately I've been working on modifying the 60 qt. Igloo cube cooler I'm going to use for my MLT.

 

[MerlinWerks]

It spins just fine with an empty hopper, no binding etc. I have the same controller you linked to ( set to max), I also have a more basic one with out the reverse switch for my stir plate, but it didn't work any different. The PC PSU wasn't any better, although it is a generic one and I would question whether it is really delivering 23A as stated.

I tried starting with an empty hopper and then adding some grain and it stalled pretty quickly. It is a mystery though, as I mentioned I bored out the coupler, if I would try to mill the shaft the way you did I'm reasonably certain I could stall it. I can slow it down to a crawl just by hand. Actually it seems to have more torque in one direction than the other, because in one direction I can stall it by hand.

I'll certainly be curious to see how you make out with it.

 

[Spellman]

I also noticed that when off you can spin in one direction with your hand, but not the other. I wonder if it needs more power to go in one direction or the other. MerlinWerks, does you motor turn if you switch it on with the dial full blast at start? I'm trying to figure out if there is something amiss with the one i have. As for the atx psu, I believe you need to tie all the rails together to get the full 23a output.