Hi All, Thanks for all your help with the vanes issue. I've decided to go with 4 vanes, 2.5cm high. I considered 6, but it seemed like the beans would tumble from vane to vane without contacting the drum at all. I have a drill now, so if I decide 6 is better, I can drill out the pop rivets. I spent much of the day working and scrounging for parts, hence the lack of emailing. Like I said, I bought a drill--the very best Black & Decker had to offer for 30 bucks. Anyway, I have a new question to ask everyone. I'd like to have it motorized...as you know, the last one was hand-cranked, which was fine, but since I'm completely rebuilding, why not motorize? Also, since I'm going to have this wonderful sample hole, it'd be a shame not to get to use it effectively. So...on to my question: I have access to about a million fans (room fans). They're free, and they all come with great motors, except that they turn far too fast. Can anyone think of a simple way of lowering the rpms? As for transformers, I can get cheap PC power supplies that supply 12 volts, but I'm not sure the motor would even turn at that voltage. Can anyone offer some suggestions? I know there're lots of engineers here, even some electrical ones, so here's your chance to shine! Cheers, --Derekhttp://uglyroaster.blogspot.com
I am going into this a little late, but I wanted to say good job. Same thing, you have decided on 4 vanes, but as food for thought, my drum technically has 6 1" vanes, except they are not full vanes. 2 are in the in the 12oclock position. Each is one third the length of the drum, one being at each end, the center open. There is a set just like that at the 6 o clock position, then there is one vane each at 3 and 9, right in the middle of the length of the drum. The effect, even at very slow rpms is constant cascading mixing in and out and back again. All I can say is the right tool for the right job is so helpful. I used a pop rivet gun for one roaster and it was ok, but on my current one I use it is nothing by sheet metal screws. Makes modifications and repairs very easy - no drilling out. As for your current question - I have a question back - do you have access to free or cheap bike parts? Instead of slowing the fan down with voltage, why not consider doing it with gears. With just 2-3 gears of different sizes you can slow it down almost to a stand still, but still have the full fan power to drive it. And that is assuming the fan motors can even drive it - all the ones I am used to stop with the slightest friction. At 06:25 8/27/2005, you wrote: <Snip> John Nanci AlChemist at large Zen Roasting , Blending & Espresso pulling by Gestalthttp://www.chocolatealchemy.com/
On Aug 27, 2005, at 8:25 AM, Derek Bradford wrote: <Snip> Put a large pulley on the drum shaft and a small one on the motor. Connect with a belt or chain, depending on the kind of pulley you use. This not only allows you to set the speed but moves the motor away from the heat. Jim Gundlach "The espresso machine is an accessory to the grinder, not the other way around."
On 8/27/05, Alchemist John wrote: <Snip> I'm using a combination of screws and pop rivets. I used the pop rivets for the drum, but for most of the housing I expect it will be screws; it has been so far. <Snip> Bike parts: I can get them. I think it would be a lot of work to align the gear assembly. I've done some robotics competitions (race ones with only a day to build), and my experience has been to avoid gears--too flimsy and not dependable in the long run. But this is leading into other stories... As for the motor stopping, I had completely overlooked that. I'm using a fan for cooling, and just figured, hey, there's a cheap motor source. I think you're right, though. There is always the option of using geared-down turning area of the motor at the back of the fan motor (you know, the one that turns the fan assembly itself?). It's got to be able to handle some resistance, since it turns the fan, which is as heavy or heavier than a drum. Any other thoughts? <Snip> tings <Snip> ribes) go tohttp://sweetmarias.com/maillistinfo.html#personalsettings<Snip> -- Check out my blog--catch up with me on YOUR schedule, not mine.http://novernae.blogspot.com
Weight is not resistance - The fan blades could be 10 lbs and once it was going, there is only air resistance to slow it down. Your drum is going to be bottom weighted (beans there) and have contact friction from the two support sides. The bottom weight is your most pressing force to overcome. In regards to robotic gears and this kind of gearing, having worked with both, it is day and night. This is gross macro gearing and I found it to be pretty easy in comparison. Micro gearing almost drove me crazy. At 07:09 8/27/2005, you wrote: <Snip> John Nanci AlChemist at large Zen Roasting , Blending & Espresso pulling by Gestalthttp://www.chocolatealchemy.com/
Could your new drill be the power source for your drum? On 8/27/05, Derek Bradford wrote: <Snip> -- "Not all things that are countable, count, and not all things that count,= are countable". Albert Einstein
I can never seem to find stainless sheet metal screws when I'm looking. Everything I see around here are zinc coated.
I am not sure what mine are, but I think they are SS - does not really matter in my case - they are all outside and not exposed to heat. At 08:45 8/27/2005, you wrote: <Snip> John Nanci AlChemist at large Zen Roasting , Blending & Espresso pulling by Gestalthttp://www.chocolatealchemy.com/
John ... weight is resistance when it comes to mass acceleration effects ... A small motor could swing it ...agreed ... but getting it there might be a problem ... of course it could take a long time to stop it as well ... Just wondering ??? <Snip>
Tom ... most ACE Hardware stores carry stainless screws and bolts ... I know the have stainless sheetmetal screws ... you might want to give them a try. My resource dried up after I retired .. so ACE is the Place !!!! <Snip>
I've thought about that. With the current trigger, it's not sensitive enough. It'll run at a low rpm, but not stably. I'd have to rewire it with a more sensitive dial switch to regulate the rpms. It would be a fun project, but to be honest I have no idea how to go about it. I suppose it would really just be a matter of rerouting the wiring through the new switch. That said, in my last robotics competition, we used dremel shafts on 12 volt circuits to power various things. I wonder if I could cheat a bit and just wire it up directly to 12 volts? That might also overcome the undersensitivity of the trigger. Thoughts? On 8/28/05, Michael Wascher wrote: <Snip> <Snip> -- Check out my blog--catch up with me on YOUR schedule, not mine.http://novernae.blogspot.com
Hi Derek, Fan motors are typically AC induction motors. They will not run on DC. = The speed of an induction motor can be controlled but they aren't the = first choice for speed control. To maintain torque at the various = speeds the controller should vary frequency as well as voltage. For use = driving a fan phase control (lamp dimmer) can be used with some success. = I have done it and I have a range hood which uses that approach. To get to the speed which you want to turn your drum and maintain = sufficient torque I would think you will need some sort of gear or = pulley arrangement at least for some of the speed reduction. With the = torque multiplication you will get with the pulley setup the phase = controlled fan motor may work. Phil
Hi Phil, Thanks for the reply. I decided to keep it simple, and I'm using the shaft that moves the fan from side to side. It turns at 20rpm, and is perfect for my drum size. It didn't require much modification, and I think it will work fine for quite a while. My shaft is a whole other matter, but I've made improvements to it as well. You can see pictures of the motor assembly on my blog http://uglyroaster.blogspot.com).Cheers, --Derek On 8/30/05, Philip Keleshian wrote: <Snip> he speed of an induction motor can be controlled but they aren't the first = choice for speed control. To maintain torque at the various speeds the con= troller should vary frequency as well as voltage. For use driving a fan pha= se control (lamp dimmer) can be used with some success. I have done it and= I have a range hood which uses that approach. <Snip> ent torque I would think you will need some sort of gear or pulley arrangem= ent at least for some of the speed reduction. With the torque multiplicati= on you will get with the pulley setup the phase controlled fan motor may wo= rk. <Snip> ribes) go tohttp://sweetmarias.com/maillistinfo.html#personalsettings<Snip> ribes) go tohttp://sweetmarias.com/maillistinfo.html#personalsettings<Snip> -- The Uglyroast Coffee Roaster. ...Now 40% less ugly!http://uglyroaster.blogspot.com
Hi Derek, That looks good. I wasn't thinking of the fans wit the gear box. When you said fan, I = was thinking one of those box fans. Phil
Derek ... you might want to look at this item on Ebay as an eg.http://cgi.ebay.com/Bodine-variable-speed-DC-gearhead-motor-w-control-N-R_W0QQitemZ7541449631QQcategoryZ71400QQssPageNameZWDVWQQrdZ1QQcmdZViewItemListed under variable speed bodine motor. Not sure the speed is to your liking, but this type of arangement works great and the motors are well known for there reliablity. Roaster looks great ...so does the coffee. Later, Bob <Snip>
Belts & pulleys. aka engine fan belt application Derek Bradford wrote: <Snip> -- Life in the fast lane ...... It is by will alone I set my mind in motion. It is by the juice of aribica that thoughts acquire speed, the lips acquire stains. The stains become a warning. It is by will alone I set my mind in motion.
You should look into rivnuts for the housing applicalation. The leave a much clearner look and allow for machince screws instead od sheet metal screws and tinnerman clips. Steve N "J.W.Bullfrog" wrote: Belts & pulleys. aka engine fan belt application Derek Bradford wrote: <Snip> -- Life in the fast lane ...... It is by will alone I set my mind in motion. It is by the juice of aribica that thoughts acquire speed, the lips acquire stains. The stains become a warning. It is by will alone I set my mind in motion.--------------------------------- Start your day with Yahoo! - make it your home page
How are you now detaching the shaft for dumping? The tryer looks sweet. At 11:19 8/29/2005, you wrote: <Snip> John Nanci AlChemist at large Zen Roasting , Blending & Espresso pulling by Gestalthttp://www.chocolatealchemy.com/
I just pull a pin from the shaft joint (where it meets the actual motor shaft). It's much more stable and secure. It will hold up much better than the old setup, though still not indefinately. I'll be visiting the welder soon enough for a proper shaft. However, even after that I'll likely keep a similar joining method; it's really quite simple and effective. It's more than strong enough. If you look at the picture of it on my blog (currently the first picture), you can see what I mean. Since the motor is mounted on the fan base, it bends backward just enough to separate it from the shaft before I tip. There's enough play overall that for now, it should suffice. On 8/30/05, Alchemist John wrote: <Snip> ttings <Snip> ttings <Snip> tings <Snip> ribes) go tohttp://sweetmarias.com/maillistinfo.html#personalsettings<Snip> -- The Uglyroast Coffee Roaster. ...Now 40% less ugly!http://uglyroaster.blogspot.com