Author Topic: New Blades for Spirit of Zubbly (Read 31695 times)

MagnetJuice · « **Reply #132 on:** April 25, 2020, 03:01:14 PM »

WOW, 50 million revolutions! Let's see how far it would have traveled if it was a 10 Ft. wheel.

I have a little time on my hands because I have to stay in my house. COVID is lurking out there somewhere, waiting for me to go out to jump on me and destroy my lungs.

6 months is 182.5 days.

A 10 Ft. diameter wheel has a circumference of 31.416 Ft.

At 200 RPM that wheel would travel 6,283 Ft. in one minute.

That is 376,980 Ft. in 1 hour. That means that the wheel is traveling at 71.4 MPH. (114.9 Km/h)

That wheel travels 1,713 miles (2,757 Km) in one day.

In 6 months, 182.5 days, she has traveled 312,732 miles (503,293 Km)

The circumference of the earth is about 24,901 miles (40,074 Km)

That means that the 10 Ft. prop-wheel could have gone 12.6 times around the earth in 6 months.

Steve could look out the window and see that sucker zooming by every 14 hours and 32 minutes at 114.9 Km/h

My brain is smoking now. I have to cool it off with a Honey Brown.

SparWeb · « **Reply #133 on:** April 25, 2020, 07:08:02 PM »

HAHAHAHAHA

richhagen · « **Reply #134 on:** April 25, 2020, 11:50:32 PM »

I believe that distance you quote is farther than the moon is from earth on average. . . . . . . .

Mary B · « **Reply #135 on:** April 26, 2020, 03:41:42 PM »

Yup about 1 1/3 times the distance from the earth to the moon.

SparWeb · « **Reply #136 on:** April 26, 2020, 10:04:31 PM »

Since we're having fun with numbers, let's go a little further.
In 6 months it's done about 50 million revolutions, as I've said. Also, my weather station reports wind speed and a bunch of other numbers including "wind run". As the name implies, the wind run is the total distance traveled by a particle in the air for any given period of time. So in 10 minutes, a 60km/hr wind will "run" 10km. For the 6 months, my weather station reports that the total wind run has been about 20 million meters.
And the 10-foot blades have a radius of 1.5 meters.

So that means we can work out...

50*10^6 * 1.5m / 20*10^6m = 3.8 = Average Tip Speed Ratio

There. You always wanted to know...

SparWeb · « **Reply #137 on:** April 26, 2020, 10:30:58 PM »

Now I'm a bit puzzled. The old bearings are clean and smooth. Of course I intend to replace them with new ones anyway (they're old enough) they show very little degradation. The rear bearings spins with a very slight... "texture" for lack of a better word. Both have a slight play allowing the inner race to move axially but not radially. While they clearly don't look new, they also seem to be in good condition.

I was expecting more degradation than this because, 1, they are many years old and 2, a vibration noise has developed over the winter.

SparWeb · « **Reply #138 on:** April 26, 2020, 10:36:06 PM »

Some pics from the disassembly process:

SparWeb · « **Reply #139 on:** April 27, 2020, 01:23:17 AM »

Thinking a bit more about the axial play in those bearings...

The rear bearing gets almost all of the thrust load. There's a wave washer on the back bearing that I'm using, but I just looked at it more closely. 3 "waves", about 0.020" thick, and the uncompressed waves make it take up about 0.15" width.

Looks a lot like this:

The difference in casing length of the motor housing, and the spacing between the bearings when pressed onto the bearing shoulders on the rotor are 7.438 and 7.375 respectively. That makes a 1/16" gap to be filled by the wave washer. That seems to compress the wave washer by about 50% and that sounds normal.

I also notice some marks on the wave washer, as if it's been spun around... it's all still a mystery...

MagnetJuice · « **Reply #140 on:** April 28, 2020, 04:48:50 PM »

I made a mistake in my calculations before. I said Steve could be seeing the wheel zooming by every 14 plus hours. It should have been every 14.53 days.

Steve, on a more serious note; are you going to rewire the motor using the same size wire and the same number of turns? I am thinking that by changing the number of turns, you can fine-tune it to the new blades if necessary.

Ed

SparWeb · « **Reply #141 on:** April 28, 2020, 08:53:45 PM »

What's there to fine-tune? C_P=0.50

This is just an opportunity for maintenance and slight improvements. The largest improvement I'm hoping for will be a stiffer electric shorting brake once I have the wires in the tower sorted out. And eliminating the vibration noise...

If I wanted a re-wind project, it would be better if I started with a fresh motor... gee, maybe I should go looking for one...

SparWeb · « **Reply #142 on:** April 28, 2020, 08:58:26 PM »

I decided to tighten the compression on the wave-washer. One of the problems with starting this project over 10 years ago is that I have forgotten lots of little details, such as what stack of washers were present in the motor when I first took it apart.

Looking for a hint, I took apart another unused motor that is similar to this Baldor. Lo and behold, there are spacer washers in it, too. That gave me some options, and perfectly sized parts that would fit on the shaft end for the 6205 bearing.

What "unused motor" you may ask...
...let's stay on topic here...

ElSuperFantasma · « **Reply #143 on:** April 28, 2020, 09:02:03 PM »

Spar,

I think you should get a new motor and show us in detail how it is done so we can follow your expertise and get things done correctly.

Just a thought

Sorry, I tend to ask for too much always.

Blessings to all of you and stay safe and healthy my friends.

Fantasma

MagnetJuice · « **Reply #144 on:** April 28, 2020, 09:21:50 PM »

I think I misinterpreted from Reply #131 when you said:

"Re-wire generator for permanent parallel-star operation only"

wbuffetjr1 · « **Reply #145 on:** April 29, 2020, 08:45:28 AM »

Quote from: SparWeb on April 28, 2020, 08:58:26 PM

What "unused motor" you may ask...
...let's stay on topic here...

Not gonna lie..... This made me perk up!!

SparWeb · « **Reply #146 on:** April 30, 2020, 11:25:08 PM »

MJ,
Oh, yes I see now that was not clear and would easily mean a re-wind of the stator. What I really meant is that the original motor was wired for 2 voltages, 240V and 480V, therefore its many various coils can be connected in series and parallel Star. In addition while I was converting it, I was interested in trying Delta connections, so I split the internal star point, and carried out the additional 3 wires. That makes for a total of 12 wires in the connection box. See the rat's nest in the photo from last week.

So now it's clear that I don't need all that stuff, but the effort to undo the star-point break wouldn't do much good, and still leave me with 9 wires that require specific connections. So never mind on the "re-wire" step, and what I've done instead is make a shorting-bar to go across the terminal block and a whole bunch of wires will be joined up there as the "parallel-star center".

SparWeb · « **Reply #147 on:** April 30, 2020, 11:45:13 PM »

I also discovered the source of the noise the generator was making, but in a rather surprising way. It wasn't the bearings, and it wasn't a bundle of wires that had wiggled loose or anything like that. It turns out that the rotor itself was coming loose on the shaft. Come to think of it, I could have been very close to a complete disaster.

The way I made the rotor originally was to push all the "stuff" from the original induction motor off of the shaft and make a completely new rotor from a solid round of steel. Nice to have that kind of stuff lying around the shop - those were the days.

The internal bore that I cut needed to press-fit onto the shaft, and I do remember getting it "not very tight" but it seemed tight enough at the time.

Fast forward a decade and the vibration from the magnet poles has wiggled it around enough that I could see play of the rotor on the shaft of at least 0.020" (1/2 mm). With that much freedom the rotor could have come free. With the magnet rotor free from the shaft, no magnetic force in the world would stop the rotor blades from spinning to oblivion. I believe the error in the bore that I cut may have come from my tool on the lathe cutting a slight taper rather than a straight cut through the center of the rotor. It would explain how one end moves and the other doesn't.

So in the end, I had to completely re-assemble the motor once with new bearings to admit that the problem wasn't actually bearings, and start investigating again. And I had to completely take it all apart again to find the wiggly rotor. Actually had to push off the end fan, too, so I had to weld that back on after I was done fixing the rotor. How does one fix an undersized rotor?

I had to stake the rotor in place. Staking involves whacking the part with a steel punch and a hammer. Yeah, a bit risky doing that with 15 cubic inches of magnet just inches away. The punch forces a small amount of material against the rotor. Do that repeatedly on both ends and the combined pressure locks the rotor back in place. That's the theory...

SparWeb · « **Reply #148 on:** April 30, 2020, 11:50:23 PM »

In the meantime, to make up for the lack of wind power coming in, I hauled over my sun-sled and hooked it up to the DC terminals at the base of the turbine. Six, count 'em, 6 glorious amps.

I wonder if the diversion controller will kick on if it's sunny all day?

kitestrings · « **Reply #149 on:** May 01, 2020, 12:49:20 PM »

"How does one fix an undersized rotor?"

I assume welding or brazing would also be risky. Interesting approach. The only other thought...(if you're not satisfied with the results)... could you perhaps drill, and pin, or perhaps those tapered roll pins... I forgotten what they are called?

A "solar-sled". Hmmm, seems like something that should propel you around the yard. ;>]

We're also missing some good winds here, but the solar output has been very steady and has allowed us a different pace. Hopefully the same for you. ~ks

Mary B · « **Reply #150 on:** May 01, 2020, 01:29:35 PM »

JB weld then stake it in a couple spots. Friend cleaned a cracked riding lawn mower crankcase, did a JB Weld patch then used it for 5 more years and that is a high stress area and very thin... with the contact surface you have it would have lasted forever!

bigrockcandymountain · « **Reply #151 on:** May 01, 2020, 01:56:43 PM »

I'm sure you are done now, but green Loctite 609 is a good fix for bearing housings that have become oversize. I usually stake with a center punch and use that stuff and it works good.

ElSuperFantasma · « **Reply #152 on:** May 01, 2020, 10:54:08 PM »

I am afraid that the vibration will not go away since the rotor attached to the shaft may not be centered anymore... I am afraid that the bearings will fail soon. Some years ago I did exactly the same thing Steven did, and the bearings failed soon after due to the unbalance of the rotor. Steven, hopefully you'll get lucky and this will not be the case and things work out good for you.

TSF

SparWeb · « **Reply #153 on:** May 02, 2020, 01:14:40 AM »

Hmmm...
I considered a weld but couldn't get comfortable with the idea. The blades are really big and have a lot of inertia - so as the wind turbine yaws around in the wind that's a big bending moment on the shaft. I don't want to weaken the shaft if I can help it.

JB weld is too viscous to get into any gaps between rotor and shaft. Brushing some on the outside won't help much.
But something runny like superglue/cyanoacrylate would wick right in. Does anyone know if Loctite responds to capillary action?
I think I'll try that tomorrow. It won't hurt, that's for sure.

mmurray70 · « **Reply #154 on:** May 02, 2020, 12:53:46 PM »

lots of options. Could bore rotor and sleeve ends for proper fit, bore/ream rotor and just make new shaft, Knurl or center punch shaft to make it bigger, weld up the shaft and turn down again, tig weld ends, etc. I've also locked things together by drilling/tapping on the intersection of 2 parts and installing set screws with loctite.

Not a real big fan of fixing anything with JB weld but it might work just fine here assuming one end is still tight enough to transfer the torque. There are loctite products designed to wick into already installed fasteners, but I dont know specific numbers, and I doubt they are designed to work with that big of gap. Good luck with it

bigrockcandymountain · « **Reply #155 on:** May 02, 2020, 03:07:16 PM »

The green loctite is quite runny. Not sure about capillary action though.

SparWeb · « **Reply #156 on:** May 02, 2020, 08:55:56 PM »

The loctite wicked in nicely. Thanks again for the idea. After the staking was done, the loctite could get into the tiny crevices.

After reassembling the generator, I gave it a test spin and boy it was very smooth. It's back on the tower and the blades are back on ready to go back up tomorrow.

While the blades were off, I took the opportunity to put more protective tape across them. This tape doesn't seem to ever come off, so I'm going to have more of it over the blade surfaces to see if it can protect the varnish finish for longer. Thanks to everyone who suggested that - I really don't know why I needed any convincing at all.

SparWeb · « **Reply #157 on:** May 03, 2020, 05:10:14 PM »

Ahhhh. Much better. It is so nice when you can make something annoying go away.

My wife asked "is it working?"
"Yes"
"But I can't hear it..."

<very funny>

MattM · « **Reply #158 on:** May 05, 2020, 12:35:13 PM »

Quote from: SparWeb on May 02, 2020, 08:55:56 PM

While the blades were off, I took the opportunity to put more protective tape across them. This tape doesn't seem to ever come off, so I'm going to have more of it over the blade surfaces to see if it can protect the varnish finish for longer. Thanks to everyone who suggested that - I really don't know why I needed any convincing at all.

I've been refreshing to see the tape in a picture. An ounce of seeing is worth a pound of hearing. Yes, this was a gratuitous request for wind turbine pr0n!

SparWeb · « **Reply #159 on:** May 05, 2020, 07:27:55 PM »

Well, even though it's 10 years old, it acts like a 3 year old child: won't stay still long enough for a decent picture. Just got blurry ones.

SparWeb · « **Reply #160 on:** May 05, 2020, 10:07:51 PM »

Try this:
https://sparweb.myportfolio.com/wind-turbines

kitestrings · « **Reply #161 on:** May 06, 2020, 03:33:15 PM »

Nice!

So, where is the blade tape now? I gotta tell you, on first look it looked like there is a big @s$ bubble on the upper right blade nearest the hub. I'm sure it is not, but I did a double-take. ~ks

SparWeb · « **Reply #162 on:** May 07, 2020, 06:01:42 PM »

My roll is 2" wide tape.
I kept adding strips until I had almost run out.

SparWeb · « **Reply #163 on:** May 07, 2020, 06:14:54 PM »

Jeez. I just double-checked the pictures to see what you were talking about. That's a reflection, but I realized something else...
That tape is so translucent you absolutely can't see it in those photos either!

You have to really zoom in close to see it.

News:

Author Topic: New Blades for Spirit of Zubbly (Read 31695 times)