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PGW Steve
Pooh-Bah

Reged: 10/03/06

Re: Gold Mtn Observatory [Re: Christopher Erickson]
#4761662 - 08/22/11 01:53 AM

It would be fairly low cost to add 2 more pillow blocks, and make a jack shaft. You could put 1 large and 1 small pulley on the jack shaft and gain quite a bit of reduction over your current set up.

Just did some math.

The motor spins at 1100 rpm.
Guessing the drive pulley is 2" and the driven is 8"
Reduction is lost due to the cable drum diameter of ~4"

This gives a speed of 287 feet per minute, or 3.76 seconds to open your 18 foot roof. This isn't accounting for accelleration, or belt slippage. You can see that the numbers show some seriously fast speed, or a lot of belt slippage.

Edited by PGW Steve (08/22/11 02:06 AM)

 Post Extras:
rwiederrich
Goldfinger

Reged: 11/17/05

Loc: Always Dark skies of Belfair W...
Re: Gold Mtn Observatory [Re: PGW Steve]
#4761988 - 08/22/11 09:59 AM

Quote:

It would be fairly low cost to add 2 more pillow blocks, and make a jack shaft. You could put 1 large and 1 small pulley on the jack shaft and gain quite a bit of reduction over your current set up.

Just did some math.

The motor spins at 1100 rpm.
Guessing the drive pulley is 2" and the driven is 8"
Reduction is lost due to the cable drum diameter of ~4"

This gives a speed of 287 feet per minute, or 3.76 seconds to open your 18 foot roof. This isn't accounting for accelleration, or belt slippage. You can see that the numbers show some seriously fast speed, or a lot of belt slippage.

Yep...I'm counting on *slippage* That is what the design is built around. When the belt is at rest and the roller bearings are not engaged...the belt is clear of the drive pulley..freeing the motor to run free. Now when I engage the bearings with the control arm I reduce the slack in the belt and slowly engage the belt to the pullies. I have an idler arm pressing against the belt from the back to keep the belt from binding against the pullies and preventing *grab*.

I know there are pleanty of mods I can perform to increase reduction...but I have ZERO funds to do this....so any suggestion that causes me to expend any cash is not a good suggestion. That's just the way it is currently.

Rob(I long for better days)

 Post Extras:
rwiederrich
Goldfinger

Reged: 11/17/05

Loc: Always Dark skies of Belfair W...
Re: Gold Mtn Observatory [Re: rwiederrich]

Here is a closeup of the system so you can see the belt orientation.

 Post Extras:
Al8236
Pooh-Bah

Reged: 08/18/10

Loc: 48.9173N 122.1390W
Re: Gold Mtn Observatory [Re: rwiederrich]
#4762238 - 08/22/11 12:16 PM

A word of warning about that arrangement, You might want to put some belt guides at the motor pulleys to hold a loop around the drive pulley if not the belt can be pulled into the drive pulley and wont disengage! and the only way to stop it would be to kill power to the motor.
With the speeds that are possible with this setup it wouldn't give you much time to react.
Al

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mikey cee
Postmaster

Reged: 01/18/07

Loc: bellevue ne.
Re: Gold Mtn Observatory [Re: Al8236]
#4762410 - 08/22/11 01:44 PM

Rob....I like your choice of motor colors. Industrial "grimey green and white". Kind'a says all business and no pretty boy electronics around this place! Mike

 Post Extras:
PGW Steve
Pooh-Bah

Reged: 10/03/06

Re: Gold Mtn Observatory [Re: mikey cee]
#4762450 - 08/22/11 02:07 PM

Another thing is, you don't want to be pushing the bearing against the belt on the same side of both drives. You want to push on the slack side, not the tension side, or you might get that bar doing bad things to the bones in your hand/arm.

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David Pavlich
Transmographied

Reged: 05/18/05

Loc: Mandeville, LA USA
Re: Gold Mtn Observatory [Re: PGW Steve]
#4762583 - 08/22/11 03:24 PM

The concept is good, but when I was working in heavy industry, I used to do a lot of safety instruction including what OSHA would say in cases like yours. I know OSHA is a non-entity on private property, however, were your setup in, say, an heavy equipment shop, the fine for your setup would be substantial. The first thing I noticed is no belt guards. We all know that we aren't going to get our hands caught in the belts, but I've seen the results of not getting hands or loose clothing stuck in a belt.

You might consider a simple guard that can be easily removed for maintenance. Also, a suggestion was made for a better idler pulley. I would try to to work toward a pulley arrangement instead of the flat surfaced bearings. It would work better to keep the belts where they're supposed to be.

David

 Post Extras:
rwiederrich
Goldfinger

Reged: 11/17/05

Loc: Always Dark skies of Belfair W...
Re: Gold Mtn Observatory [Re: Al8236]
#4762625 - 08/22/11 03:54 PM

Quote:

A word of warning about that arrangement, You might want to put some belt guides at the motor pulleys to hold a loop around the drive pulley if not the belt can be pulled into the drive pulley and wont disengage! and the only way to stop it would be to kill power to the motor.
With the speeds that are possible with this setup it wouldn't give you much time to react.
Al

I thought of that...the initial load on the belts is enough that even if the belt *grabbed* when the bearing activation lever was disengaged.it would slip anyway. The reason for the idler shaft/bearing behind the belt. It created a situation in the belt that it springs past the drive pulley and just isn't close enough to engage the drive pulley.

I've run it in slow motion..and at full speed to see the effects...in both directions. It slips until the bearing lever is engaged adequately.

I will probably place guides for extra added safety.

Rob

 Post Extras:
rwiederrich
Goldfinger

Reged: 11/17/05

Loc: Always Dark skies of Belfair W...
Re: Gold Mtn Observatory [Re: mikey cee]
#4762645 - 08/22/11 04:04 PM

Have I EVER done anything to impress the guys who like pretty? I do what it takes..even it goes against the acceptable.

Rob(I do it my way)

 Post Extras:
rwiederrich
Goldfinger

Reged: 11/17/05

Loc: Always Dark skies of Belfair W...
Re: Gold Mtn Observatory [Re: PGW Steve]
#4762666 - 08/22/11 04:13 PM

Quote:

Another thing is, you don't want to be pushing the bearing against the belt on the same side of both drives. You want to push on the slack side, not the tension side, or you might get that bar doing bad things to the bones in your hand/arm.

I thought of that..if you look at the closeup you will see a bar on the backside of the belt..this bar is loaded on a doulbe bearing housing..so it easily rotates as the belts roll against it..second the action angle of the bearings that are on the control arm are at such an angle as to not induce back force from the drive side of the belts.

Here is the fun part...it works and works well.

Just more of my crazy(I did it my ways tuff that baffles most rational thinkers.

Rob

 Post Extras:
rwiederrich
Goldfinger

Reged: 11/17/05

Loc: Always Dark skies of Belfair W...
Re: Gold Mtn Observatory [Re: David Pavlich]
#4762691 - 08/22/11 04:27 PM

Quote:

The concept is good, but when I was working in heavy industry, I used to do a lot of safety instruction including what OSHA would say in cases like yours. I know OSHA is a non-entity on private property, however, were your setup in, say, an heavy equipment shop, the fine for your setup would be substantial. The first thing I noticed is no belt guards. We all know that we aren't going to get our hands caught in the belts, but I've seen the results of not getting hands or loose clothing stuck in a belt.

You might consider a simple guard that can be easily removed for maintenance. Also, a suggestion was made for a better idler pulley. I would try to to work toward a pulley arrangement instead of the flat surfaced bearings. It would work better to keep the belts where they're supposed to be.

David

I appreciate your input..but have you noticed the location of the motors? Up at learly 8ft from the floor. No hand or clothews will get up there to get cought.

Both of my idler bearings have guides along side of them to aid in guiding the belt evenly. I plan on fabricating a cover to help hide the motors at some time. I know OSHA would have a fit...but most of what I do would find issue with them. I'm just outta luck.

Rob

 Post Extras:
mikey cee
Postmaster

Reged: 01/18/07

Loc: bellevue ne.
Re: Gold Mtn Observatory [Re: rwiederrich]
#4762749 - 08/22/11 05:07 PM

Quote:

Quote:

The concept is good, but when I was working in heavy industry, I used to do a lot of safety instruction including what OSHA would say in cases like yours. I know OSHA is a non-entity on private property, however, were your setup in, say, an heavy equipment shop, the fine for your setup would be substantial. The first thing I noticed is no belt guards. We all know that we aren't going to get our hands caught in the belts, but I've seen the results of not getting hands or loose clothing stuck in a belt.

You might consider a simple guard that can be easily removed for maintenance. Also, a suggestion was made for a better idler pulley. I would try to to work toward a pulley arrangement instead of the flat surfaced bearings. It would work better to keep the belts where they're supposed to be.

David

I appreciate your input..but have you noticed the location of the motors? Up at learly 8ft from the floor. No hand or clothews will get up there to get cought.

Both of my idler bearings have guides along side of them to aid in guiding the belt evenly. I plan on fabricating a cover to help hide the motors at some time. I know OSHA would have a fit...but most of what I do would find issue with them. I'm just outta luck.

Rob

OSHA has probably caused more premature deaths and suicides than the lives it has "saved". It's bound to be that way when government get's it's paws in the mix. Mike

 Post Extras:
rwiederrich
Goldfinger

Reged: 11/17/05

Loc: Always Dark skies of Belfair W...
Re: Gold Mtn Observatory [Re: mikey cee]
#4762821 - 08/22/11 05:42 PM

Quote:

Quote:

Quote:

The concept is good, but when I was working in heavy industry, I used to do a lot of safety instruction including what OSHA would say in cases like yours. I know OSHA is a non-entity on private property, however, were your setup in, say, an heavy equipment shop, the fine for your setup would be substantial. The first thing I noticed is no belt guards. We all know that we aren't going to get our hands caught in the belts, but I've seen the results of not getting hands or loose clothing stuck in a belt.

You might consider a simple guard that can be easily removed for maintenance. Also, a suggestion was made for a better idler pulley. I would try to to work toward a pulley arrangement instead of the flat surfaced bearings. It would work better to keep the belts where they're supposed to be.

David

I appreciate your input..but have you noticed the location of the motors? Up at learly 8ft from the floor. No hand or clothews will get up there to get cought.

Both of my idler bearings have guides along side of them to aid in guiding the belt evenly. I plan on fabricating a cover to help hide the motors at some time. I know OSHA would have a fit...but most of what I do would find issue with them. I'm just outta luck.

Rob

OSHA has probably caused more premature deaths and suicides than the lives it has "saved". It's bound to be that way when government get's it's paws in the mix. Mike

Just another good reason why I'm running amuk......

I'm a free Runnamuker

Rob

 Post Extras:
rwiederrich
Goldfinger

Reged: 11/17/05

Loc: Always Dark skies of Belfair W...
Re: Gold Mtn Observatory [Re: rwiederrich]
#4764815 - 08/23/11 05:27 PM

It's clearing enough tonight I will connect the runout cables and run the roof out...then connect the runin cables and run it in. I will exercise the roof several times...then hopefuly do some viewing trying out my new scope drives.

Fun fun fun

Rob

 Post Extras:
rwiederrich
Goldfinger

Reged: 11/17/05

Loc: Always Dark skies of Belfair W...
Re: Gold Mtn Observatory [Re: rwiederrich]
#4772303 - 08/27/11 02:34 PM

Well...not to go deep into the reasons..I had to change out the the large 110vac motors. They just didn't have the torque needed...si I found a nice 110vac motor with a reduction gear head mounted. The motor runs at 1200rpm and is reduced to 6rpm. So I removed the pullies and added a chain system. I don't have any pics now..but soon.

That is part of the post....with the roof run out...I enjoyed the 10"f/15 all night. OH boy...the new drive motors I added work awesome. The clock one is easily adjusted and the RA drive is waaay better and faster then the old stepper motor...and so much more reliable.

I spent the entire night out. I viewed every major object I could find in each constillation. I ran the scope at full aperature...and I was stunned at the image scale and brightness of the objects....namely M13(example). With a 32mm EP M13 took up nearly the entire field of view...spot on tracking and the resolution was so impressive I spent 30 minutes alone on it.

My decision to add all the axii controls and the focus control to the hand controler...was ingenious.

I viewed doubles planitary nebulea........everything tyhat rose. An extra added bonus..was that even thought it was clear, the seeing was awesome...with little atmospheric issues. Splitting the double double was a no brainer with the 32mm....fantastic split.

I played..till Jupiter rose...and the most fancinating thing was one of its moons was acculting and its shadow was easily sean crossing the disc. I chose to stop the scope down to 8" at this time to control residual color issues.

It all went away without effecting the image. I watched this celestial vision for an hour or so..watching the moor cross the disc and the shadow....what a treat.

I then prepared for Pegesus and Andromeda. Good Lord!
I couldn't fit the entire gallaxy in the field of view...even with the 32mm. The secondary gallaxy was also easily visible. Man..I could never view with such magnitude and image scale with my 6"f/15. 10" is awesome for DSO's.

More play and I viewed the Pleadies and stayed strong till Orion was ready for my objective. It was like a kid cut loose in a candy store....I can't even describe it.

Well....I came in at dawn and am ready to go out and close up the roof. I have a bit more work to do on connecting the draw-in cables to the drums that will draw them in.

What an awesome night...best of the entire year by far.

I had soft music playing on the OB stareo and a nights treat was had. OH boy.

Rob(I am so freeking happy)

 Post Extras:
Ecurb
member

Reged: 05/16/08

Loc: Kirkwood, California
Re: Gold Mtn Observatory [Re: rwiederrich]
#4775118 - 08/29/11 05:55 AM

Hi Rob,

6 rpm sounds much, much, much better. With a chain drive, there will be no slipping, and your new motor will probably produce lots of torque. You really should have some way to add "limit switches" so that in case the operator is "asleep at the wheel", you have some way to protect against running the roof into the end of the track and breaking something. If you can't do limit switches, maybe add a "weak link" or springs where the cable attaches to the roof.

Good to hear about the great views!! Wish I lived close enough to check out your big 10 inch (the f/15). The photos are awesome.

Bruce

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BluewaterObserva
Postmaster

Reged: 05/18/04

Re: Gold Mtn Observatory [Re: Ecurb]
#4775473 - 08/29/11 10:41 AM

Man... Nice to hear you using your setup.. Enjoying it!!

I think we actually started our observatorys around the same time?

 Post Extras:
rwiederrich
Goldfinger

Reged: 11/17/05

Loc: Always Dark skies of Belfair W...
Re: Gold Mtn Observatory [Re: Ecurb]
#4776223 - 08/29/11 04:42 PM

Quote:

Hi Rob,

6 rpm sounds much, much, much better. With a chain drive, there will be no slipping, and your new motor will probably produce lots of torque. You really should have some way to add "limit switches" so that in case the operator is "asleep at the wheel", you have some way to protect against running the roof into the end of the track and breaking something. If you can't do limit switches, maybe add a "weak link" or springs where the cable attaches to the roof.

Good to hear about the great views!! Wish I lived close enough to check out your big 10 inch (the f/15). The photos are awesome.

Bruce

Yeah the chain drive is sweet..however the motor still isn't fast enough..and 6 rpm isn't fast enough for me. I do have one cool thing going for me The motor has an external shaft out both ends...one with the reduction(5/8" shaft) and out the back end(1/2") I can easily attach another motor to it that runs faster to make the output go from 6rpm to 12 or faster. I found out the hard way that the motor isn't reversible....but if I attach another motor it can be refersible and still drive the gear head.

In short...I can simply use the motor as a passive connection for a faster motor to the gear head.

I'm on the search for a fast 110vac reversible motor now. I do have one that runs at 13,000 rpm but it runs in the same direction as the motor attached to the gear head.

Thanks for the compliments and yes the viewing here the last several days has been awesome.

My new drives for the RA and DEC for the scope are working beautiful as well. 2 simple gearhead 12v motors..what a joy to slew the scope now.

Rob(You're always welcome)

 Post Extras:
rwiederrich
Goldfinger

Reged: 11/17/05

Loc: Always Dark skies of Belfair W...
Re: Gold Mtn Observatory [Re: BluewaterObserva]
#4776235 - 08/29/11 04:48 PM

Quote:

Man... Nice to hear you using your setup.. Enjoying it!!

I think we actually started our observatorys around the same time?

Nearly the same time John...you, however, were rebuilding that dome long before I ever started.

I'm so impressed with the scopes drives and the one single grip control for scope slewing and focus.

The star tests for this objective are textbook. Identical in and out of focus defraction rings.....

I'm so happy.

Rob

 Post Extras:
Ecurb
member

Reged: 05/16/08

Loc: Kirkwood, California
Re: Gold Mtn Observatory [Re: rwiederrich]
#4777358 - 08/30/11 05:46 AM

Rob,

Can't you just gear-up the motor? Put a larger sprocket on the motor and a smaller one on the "drum drive". Many AC motors are reversible, although if the name plate says it isn't, it probably isn't. Another option would be to go for a DC motor. They are almost always easily reversible. And surplus ones are cheap. Like from an electric "ride on" child's toy or a scooter. Check out "Good Will", etc., for one with broken wheels, body, frame, but a good motor.

Bruce

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