| Post Info | TOPIC: Mechanical Questions |
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jackisback
Member
Posts: 7
Date: Feb 9, 2010
| RE: Mechanical Questions |
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| It sounds like you are looking for some type of locking collar with a keyway to go with a mounting bracket. Locking collars are available at http://www.usabearingsandbelts.com/ I am not sure if you can replace a bearing with the locking collar. This also assumes that you will use a keyed shaft which you can pick up from http://purvisindustries.com/pbs.html. |
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dereksoftstuff
Veteran Member
Posts: 35
Date: Feb 8, 2010
| RE: Mechanical Questions |
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lots of stuff here (UK)
http://simplybearings.co.uk/shop/index.php
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Hobby VAWT
Member
Posts: 22
Date: Feb 8, 2010
| RE: Mechanical Questions |
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I use the same bearing, except it is sized for a 1" shaft. Just make sure the oil fitting is tight. Ive actually received them where the fitting was laying in the packing material.
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Project
Veteran Member
Posts: 97
Date: Feb 8, 2010
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Zapmk
Veteran Member
Posts: 49
Date: Feb 7, 2010
| RE: Mechanical Questions |
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| Go Kart shops are a good place to source bearings rotors etc.  |
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sjh7132
Guru
Status: Online
Posts: 1231
Date: Feb 7, 2010
| Mechanical Questions |
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| electrondady1 wrote:
i think that would qualify as a mandrel
Not exactly what I was thinking of. I want something like this:  That clamps to the shaft, so this piece and the shaft move as a single unit. -- Edited by sjh7132 on Sunday 7th of February 2010 11:04:12 PM
Steve
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electrondady1
Senior Member
Posts: 428
Date: Feb 7, 2010
| RE: Mechanical Questions |
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i think that would qualify as a mandrel
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sjh7132
Guru
Status: Online
Posts: 1231
Date: Feb 7, 2010
| RE: Mechanical Questions |
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| wiboater wrote:
Someone gave a site called the bigbearingstore.com It has good prices on pillow blocks with bearings. Other places you could get them would depend on what state your in. In Wisconsin Mills Fleet farm stores carry bearings and pillow blocks in the farm section. Also Motion Industries has bearings. You can either use pillow blocks and let the shaft rotate. or you can use the flat bearing supports and have the shaft stationary with the wings rotating around it.
I was looking at the bigbearingstore.com and they have lots of bearings. But now I want something that will clamp to the shaft to hold the supports for my wings. What would that part be called? A shaft collar seems close by donsn't have anything to bolt to.
Steve
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wiboater
Senior Member
Posts: 242
Date: Feb 7, 2010
| RE: Mechanical Questions |
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| Someone gave a site called the bigbearingstore.com It has good prices on pillow blocks with bearings. Other places you could get them would depend on what state your in. In Wisconsin Mills Fleet farm stores carry bearings and pillow blocks in the farm section. Also Motion Industries has bearings. You can either use pillow blocks and let the shaft rotate. or you can use the flat bearing supports and have the shaft stationary with the wings rotating around it. |
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sjh7132
Guru
Status: Online
Posts: 1231
Date: Feb 7, 2010
| RE: Mechanical Questions |
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Okay lets say I came up with a design were the shaft could spin using a couple of pillow bearings. How do you guys attach things to the shaft? Is there such a thing as a shaft flange? Can anyone tell me where they are sold? I've done a quick search on the word without much luck.
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Steve
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Zapmk
Veteran Member
Posts: 49
Date: Jan 27, 2010
| Mechanical Questions |
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Steve you could be right, don't know.
ED made a reply to one of my postings on OP, http://www.fieldlines.com/comments/2006/6/20/14712/0791/16#16 at that time I was going to build an 8 X 16, Ed came up with 3600 ft pounds, so the 2700 ft pounds of the 8 X 12 seamed right in line.
Maybe ED will pop in and clarify.
-- Edited by Zapmk on Wednesday 27th of January 2010 04:29:49 AM
-- Edited by Zapmk on Wednesday 27th of January 2010 04:37:08 AM
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sjh7132
Guru
Status: Online
Posts: 1231
Date: Jan 27, 2010
| RE: Mechanical Questions |
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| Zapmk wrote:
Assuming I did this right, .00492 X wing area(sq ft) X windspeed (mph)^2 = force in lbs
My 8 X 12 will have an wing area of 38.4 sq ft (one wing)
So, in a 60 mph wind
.00492 X 38.4 X 3600 = 680.1 take that X arm length of 4 foot = 2720.5 pounds of force on the wing.
Actually I think that area is supposed to be the swept area of the turbine, not the area of the wing or wings. You'd only use the area of the wings if you brought your turbine to a stop in a high wind.
Steve
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Zapmk
Veteran Member
Posts: 49
Date: Jan 27, 2010
| RE: Mechanical Questions |
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Assuming I did this right, .00492 X wing area(sq ft) X windspeed (mph)^2 = force in lbs
My 8 X 12 will have an wing area of 38.4 sq ft (one wing)
So, in a 60 mph wind
.00492 X 38.4 X 3600 = 680.1 take that X arm length of 4 foot = 2720.5 pounds of force on the wing.
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keithturtle
Senior Member
Posts: 173
Date: Jan 27, 2010
| RE: Mechanical Questions |
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What are the units for area, sq in or sq ft?
What are the units for velocity, ft/sec,
Assuming those from the force in pounds
Turtle, learning
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Soli Deo Gloria |
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Zapmk
Veteran Member
Posts: 49
Date: Jan 26, 2010
| Mechanical Questions |
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| Ed lenz put a little fear in me one time about now much loading you could have on the wings. .00492 x wing area x windspeed^2 = force in lbs. Take the force x arm length for torque. Maybe overkill? 8 X 12 going to turn on a 2.5" solid shaft with a piece of 1/4 wall pipe over the shaft in between bearing assemblies,all in-cased in a 5" aluminum tube, no top support needed. still waiting on the waterjet guy for the arm rotors, arms and wing ribs.  -- Edited by Zapmk on Wednesday 27th of January 2010 12:06:28 AM-- Edited by Zapmk on Wednesday 27th of January 2010 12:14:24 AM |
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stonebrain
Veteran Member
Posts: 78
Date: Jan 26, 2010
| RE: Mechanical Questions |
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I agree,the spindle of a trailer hub is steel,not just iron,a lot stronger,that makes it a lot lighter for the same strength.
You can bolt a piece of tubing on it as axe for the vawt rotor.I guess it would be a good choice.
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electrondady1
Senior Member
Posts: 428
Date: Jan 26, 2010
| RE: Mechanical Questions |
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steve,
that trailer hub is very strong.
i don't think you will have any trouble building a wind turbine on it.
they mention a load of just over 1200 lbs.
what is that in comparison to the total side load on your mill ?
swept area x the pressure of the wind
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Caleb
Senior Member
Posts: 473
Date: Jan 26, 2010
| RE: Mechanical Questions |
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| wiboater wrote:
I figured that but just couldn't resist kidding a little. As far as the diameter of the turbines go I think a little narrower is probably better to keep up the RPM's. I'm no expert though.
Actually, the more I think about it, I am probably getting less power ... like 2.5 to 3 Watts long term average. So maybe it wasn't all that far off. Tall and narrow would be good (Windspire) but it gets harder to get a lot of area. We have zoned height restrictions in our area so that is another limit. I might try a chain or belt drive sometime for grins because magnets are expensive. Steve, would it be helpful to have a few back-of-the-envelope equations to calculate an appropriate shaft diameter?
- Bryan
Mechanical Engineer turned stay-at-home dad. |
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wiboater
Senior Member
Posts: 242
Date: Jan 26, 2010
| RE: Mechanical Questions |
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I figured that but just couldn't resist kidding a little. As far as the diameter of the turbines go I think a little narrower is probably better to keep up the RPM's. I'm no expert though.
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Caleb
Senior Member
Posts: 473
Date: Jan 26, 2010
| Mechanical Questions |
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| wiboater wrote:
20 ft tall and 30 ft diameter. I think they call that a merry go round. :)
That was a bit of an exaggeration. I've got a turbine with an area of 0.36 m^2 and I was hoping it would produce about 4.5 Watts on a long term average. But it probably does about 4 Watts tops. We use about 12 kWh of power a day; about 500 W continuous. So I figured if half of that was supplied by the wind (250 W) I would need 250/4=62.5 turbines or an area of 22.5 m^2 (242 ft^2); we don't have a lot of wind. So 20 ft high and 12 ft in diameter would be closer to the truth. Sorry to get off topic. -- Edited by Caleb on Tuesday 26th of January 2010 01:06:56 PM
- Bryan
Mechanical Engineer turned stay-at-home dad. |
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wiboater
Senior Member
Posts: 242
Date: Jan 26, 2010
| RE: Mechanical Questions |
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There's a few way's you can go , you can build a square tubing frame around it like I have. It gives you the advantage of being able to guy wire it if you need to and gives support on both ends for bearing mounting. You could go with just a 2 or 3 inch diameter rigid pipe and have the bearings rotating around that something like Cole J's drawing on the home page. You could have something like David Zeeeeee's got , more of a C type support. The pipe you would need a base that would tip up if it's really tall. If not you could bury a sonotube and just slip it into the hole. Rob's rotor hub style would probably work well for you for changing wing designs. The cost on mine with the square tubing wasn't that bad. If you buy from a steel supplier it's a lot cheaper than a hardware store . I'd say I have less than $100.00 in the whole frame, shaft and bearings. I welded mine but you could drill and bolt one together.
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wiboater
Senior Member
Posts: 242
Date: Jan 26, 2010
| RE: Mechanical Questions |
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| 20 ft tall and 30 ft diameter. I think they call that a merry go round. :) |
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sjh7132
Guru
Status: Online
Posts: 1231
Date: Jan 26, 2010
| RE: Mechanical Questions |
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| Caleb wrote:
What will your neighbors say? :-) I'm thinking that to do it right, I'd need a turbine about 20 feet tall and 30 feet in diameter. My wife might object, but ...
Well I was thinking that 4m^2 of 15MPH wind would be about 600 watts of power in the wind. If I can harness 40% of that, it will be 250 watts or so. It won't power my house, but at least its significant. If it works out, I'll put in a second one. I'm hoping to find a low solidity design that isn't very visible. When I was talking to the people on my HOA, they referenced my 7ft HAWT as 'your little turbine'. To me that's a sign I should go bigger. :-)
Steve
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Caleb
Senior Member
Posts: 473
Date: Jan 26, 2010
| Mechanical Questions |
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What will your neighbors say? :-) I'm thinking that to do it right, I'd need a turbine about 20 feet tall and 30 feet in diameter. My wife might object, but ...
-- Edited by Caleb on Tuesday 26th of January 2010 03:02:41 AM
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- Bryan
Mechanical Engineer turned stay-at-home dad. |
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sjh7132
Guru
Status: Online
Posts: 1231
Date: Jan 26, 2010
| RE: Mechanical Questions |
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| vawtman wrote:
You got a ways to go yet Steve.The best way to learn is to build and understand the principals involved and it will evolve for ya.The rotor arms must be tied has one also.
Forget the dag gum sims and JUST DO IT you will learn more i would say:)
I would like to get the main structure right the first time, since it's going to be significant money to build this. I was thinking of a generic pole, shaft, arms and alt that I could try different wings on.
Steve
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sjh7132
Guru
Status: Online
Posts: 1231
Date: Jan 26, 2010
| RE: Mechanical Questions |
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If you have a large diameter VAWT, isn't it hard to support the shaft from the top?
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Steve
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vawtman
Senior Member
Posts: 251
Date: Jan 26, 2010
| RE: Mechanical Questions |
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oops forgot and tower.
Bed time
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vawtman
Senior Member
Posts: 251
Date: Jan 26, 2010
| RE: Mechanical Questions |
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Flexing of the shaft is a none factor here has long has the shaft is supported properly by it's bearings.
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wiboater
Senior Member
Posts: 242
Date: Jan 26, 2010
| RE: Mechanical Questions |
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if your worried about shaft flex just go with steel tubing and use a diameter that's big enough so it won't flex. The tubing will be lighter and cheaper to buy. I just go to a local steel supplier to buy mine. you can get the tubing with different wall thickness depending on your needs. I have been using 1" tubing with about 1/8 inch thick wall for my lenz turbines. mine are supported at both ends in bearings though. The part that's going to fly apart would be the wings anyway. :)
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Caleb
Senior Member
Posts: 473
Date: Jan 26, 2010
| RE: Mechanical Questions |
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| sjh7132 wrote:
I'm used to my 1/2" threaded rod pretty much bending under it's own weight if it's longer than 36". My 2ft x 16" turbine really bends that rod in a 10 MPH wind.
How strong is real shaft material, say 1"? Would it take the side load of a 4M^2 turbine in 15 MPH winds if it was 36" long?
I have no gut feeling for how strong that stuff is. Could a person stand on one of those shafts if it were supported by both ends, or would it bend?
If the turbine is supported on both ends and the bearings are located near the supports, a 1" diameter rod should be more than adequate since the blade forces will be acting near the ends of the rod and not in the middle. And 3ft is not all that long. If you go to tractor supply, sometimes they have steel stock in a rack. You can pick up a few pieces and see if you can flex them. That would give you a good feel for their strength. When I was designing machines, a lot of times I just picked stock that looked about right. Once in a while I would go to the machine shop and pick up a few pieces to get a better idea of their strength. In cases when weight was critical or the chunk of steel was large, I would calculate the stresses, deflection and if necessary natural frequency.
- Bryan
Mechanical Engineer turned stay-at-home dad. |
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vawtman
Senior Member
Posts: 251
Date: Jan 26, 2010
| RE: Mechanical Questions |
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You got a ways to go yet Steve.The best way to learn is to build and understand the principals involved and it will evolve for ya.The rotor arms must be tied has one also.
Forget the dag gum sims and JUST DO IT you will learn more i would say:)
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sjh7132
Guru
Status: Online
Posts: 1231
Date: Jan 26, 2010
| RE: Mechanical Questions |
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| vawtman wrote:
So the theory of vawts thowin blades all over the world is bogus.The hawt is a much scarier animal.Never could convince the hawties of that in my time at op.
Mark
I agree with you there. So far I've had two HAWTs self destruct, 0 VAWTs.
Steve
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Caleb
Senior Member
Posts: 473
Date: Jan 26, 2010
| RE: Mechanical Questions |
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I like poking around Tractor Supply for various mechanical parts.
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- Bryan
Mechanical Engineer turned stay-at-home dad. |
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sjh7132
Guru
Status: Online
Posts: 1231
Date: Jan 26, 2010
| RE: Mechanical Questions |
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I'm used to my 1/2" threaded rod pretty much bending under it's own weight if it's longer than 36". My 2ft x 16" turbine really bends that rod in a 10 MPH wind.
How strong is real shaft material, say 1"? Would it take the side load of a 4M^2 turbine in 15 MPH winds if it was 36" long?
I have no gut feeling for how strong that stuff is. Could a person stand on one of those shafts if it were supported by both ends, or would it bend?
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Steve
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vawtman
Senior Member
Posts: 251
Date: Jan 26, 2010
| RE: Mechanical Questions |
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For that a 1.25 in shaft should suffice with bearing support like what i did.I found with a solidity around .3 the foil will stall.Like a plane goin too slow in little round circles :)
So the theory of vawts thowin blades all over the world is bogus.The hawt is a much scarier animal.Never could convince the hawties of that in my time at op.
Mark
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sjh7132
Guru
Status: Online
Posts: 1231
Date: Jan 26, 2010
| RE: Mechanical Questions |
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| vawtman wrote:
What size we talkin Steve?When you get into bigger turbines you need MEAT :) and not just a trailer hub at the base.Not only for the side loading but also the centrifical force involved in the beast.
Okay I guess I should define big, because I wasn't thinking 21 feet. :-) I was thinking maybe 1M radius (2M diameter) and maybe 1 to 2 meter long blades. I really want the size because I don't have high winds here very often. If a strong wind does come up I'd probably stall the blades to reduce drag.
Steve
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davidzeeeeee
Veteran Member
Posts: 26
Date: Jan 26, 2010
| RE: Mechanical Questions |
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My self, I went from a five foot turbine to a 21 foot turbine. For bearings, shaft collars, pulleys, sprockets....I use The Big Bearing Store.com... Best prices so far. For motors, timers, ...Surplus shops. I almost never pass up a barn/garage/yard sale or flea market, ask my wife.
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David Zeeeeeee |
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vawtman
Senior Member
Posts: 251
Date: Jan 26, 2010
| RE: Mechanical Questions |
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What size we talkin Steve?When you get into bigger turbines you need MEAT :) and not just a trailer hub at the base.Not only for the side loading but also the centrifical force involved in the beast.
It's a whole different animal than the toys.Mine could drag cement blocks on the ground back in the day in high winds.
It's fun
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sjh7132
Guru
Status: Online
Posts: 1231
Date: Jan 25, 2010
| Mechanical Questions |
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| I'm pretty good at electronics and computers, but when it comes to making mechanical things, especially out of heavy metal I have no experience. Up to now, all my turbines have been small and based on 1/2" threaded rod that I got from Home Depot. I'm now considering making something bigger and more heavy duty, so I'm asking for some advice here. To start with, I have to find a shaft and bearings. I was considering basing my mill on a trailer hub something like this. Link here Any comments? Is there a cheaper way to do it? For some reason all my turbines have had a stationary shaft with something spinning around that shaft. This kind of fits that pattern. Any input would be appreciated.
Steve
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