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Post by Ron Walker on Aug 24, 2022 10:56:28 GMT -7
The diurnal drive shaft which runs through the west side longitude shaft enters the center box and powers a timing belt which brings the drive motion out to a shaft which runs the worm gear for the diurnal motion.
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Post by Ron Walker on Aug 24, 2022 10:59:53 GMT -7
Posted by: Ron Walker Nov 8 2007, 03:31 PM Again note the large blocks of aluminum and the thick sheets used in the construction of this projector. Built very much like a prototype. It is built like a tank and will probably last another 40+++ years with no problems at all.
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Post by Ron Walker on Aug 24, 2022 11:01:52 GMT -7
Inside the two main bearings on the east west axis are two sets of slip rings which carry 16 circuits each to the central core. Here is a set before cleaning..... .....and after. Here are a few Q-tips after just cleaning one set of slip rings. The projector uses graphite brushes and thus are self lubricating. The amount of wear is slight considering the age of the unit and I would not expect needing replacements for the brushes anytime in the near future.
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Post by Ron Walker on Aug 24, 2022 11:02:33 GMT -7
Posted by: Owen Phairis Nov 8 2007, 03:35 PM QUOTE(Ron Walker @ Nov 8 2007, 09:59 AM) * As the re-build takes place all questions will be answered. But I can answer this one first.
The bottom of the A3P mounting plate contains two DC motors. One for diurnal motion and one for latitude motion.
Looking directly up at the bottom of the main support plate we can see the two motors and the various terminal strips used to connect the various functions of the projector. Two of these strips send wires up the hollow support posts into the projector via slip rings. The other two supply power to the many auxiliary plugs that are built into the base.
Ron,
Those sure look just like AC Bodine synchrous motors with gerabox. Interesting that they would look so identical.....
Owen
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Post by Ron Walker on Aug 24, 2022 11:05:50 GMT -7
Posted by: Ron Walker Nov 8 2007, 03:40 PM In order to speed up the process of cleaning and lubricating the unit, I removed the worm drive so that the central core could be rotated quickly and easily. The central core also houses a set of 24 slip rings that rotate with diurnal motion. Here is a Q-tip in cleaning position. Once cleaned, the re-lubricated worm with its associated bearings are re-bolted into place. Once one understands exactly how this machine is built, repair and/or modification is a snap.
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Post by Ron Walker on Aug 24, 2022 11:06:29 GMT -7
Posted by: Ron Walker Nov 8 2007, 03:51 PM QUOTE(Owen Phairis @ Nov 8 2007, 03:35 PM) * Ron,
Those sure look just like AC Bodine synchrous motors with gerabox. Interesting that they would look so identical.....
Owen
They are indeed motors made by Bodine and I originally had the same thought that you did. Since the planet cage is totally driven and interlocked via synchronous drive motors I expected the rest of the projector to be driven the same way. Looking at the drive schematics I noted the DC power supplies. Originally I thought that I was going to replace these motors with DC ones as DC drives offer a ton of torque at variable speeds. When I actually looked at the motor and confirmed they were indeed DC type and experiment was in order. By just simply placing a full wave rectifier after a variac, I was able to get an output of from a day in one minute to a day in six minutes. I now plan to use these exsisting motors but add a two to one gear reduction so that I will have a day in two minutes down to a day in twelve minutes which I really wanted. If I ever want more speed control, there are new motor systems that will double that range but I believe I will be happy with what I have.
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Post by Ron Walker on Aug 24, 2022 11:12:09 GMT -7
Posted by: Ron Walker Nov 8 2007, 04:46 PM Now that I had the central core finished, I turned to the planet cage. This will take some time because this is where I plan the most modification. As most of you are familiar, the A3P and later projectors use AC synchronous motors to "lock" the various planet analogs together. This works great as long as the motors are receiving power and that their speed is not changed too rapidly, not allowing the "magnetic sprockets" to slip. One of the big problems that I have heard about this machine is the problem with holding the various planet analogs together in sync. My first thought was why not just tie all of them together mechanically like the original Zeiss which have more then once proved the dependability of the mechanical design. I have been told that another reason for this design is the ease of changing the positions of the planets from one epoch to another. Well, it really will stay easy if my plans hold true. One must remember that each analog must provide points for the planet projected, the Earth, and the Sun in order to position the planet properly on the projection dome. Since there is a separate analog for each planet then these three positions must be duplicated in each device. All of the gearing necessary is driven by one motor for each planet analog. Once everything is in alignment then there is no reason to need to change anything unless one plans to move drastically in time for a particular show. One thing that never needs to change is the relationship between the Sun and Earth positions in each of the analogs as they must be identical in each for the projections to be accurate. Thus, why not tie them all together and run them with one DC drive motor. The projector will probably hold planet accuracy much better this way then the original design. While I am just getting started on this section of the projector, I will take you as far as I've progressed. I now need to order tools and drive components to move further. First we see the entire planet cage removed from the A3P. The motor housing shroud has been removed in this picture. It is a thin sheet of brass that covers the area where the motors reside. Next is a view from the top of the assembly, the place where it attaches to the central core.
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Post by Ron Walker on Aug 24, 2022 11:16:27 GMT -7
Posted by: Ron Walker Nov 8 2007, 05:01 PM The top plate of the planet cage (the plate that attaches to the central core) holds the various switches that are used to move the individual analogs for alignment. Once modified they will no longer be necessary. Also attached are the plugs for all the individual motors. Once removed, all of the analog motors are exposed. It is now very easy to remove the motors and reveal the drive shafts for the individual analogs. While much of this part of the projector came apart with the use of a 0.05 Allen wrench, the smallest I have ever used. There are many more parts that I must remove that have smaller set screws. New tools must be purchased before I can go further on this part of the projector. More will come as I progress further. Now I will go back to working on the control unit which will be designed to work both projectors.
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Post by Ron Walker on Aug 24, 2022 11:16:58 GMT -7
Posted by: stlfiremedic35 Nov 8 2007, 07:09 PM hey Ron that looks kind of like the voyager space probe to me! If you get that working can you start on a time machine for me? Ha would liketo see it in action when it all together.
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Post by Ron Walker on Aug 24, 2022 11:17:33 GMT -7
Posted by: charles jones Nov 9 2007, 01:36 AM Ron,
thank you so much for taking the time to photograph all this stuff. It'll help me tremendously in the design of mine. I have also considered the mounting of the motors in the base as you suggested some time ago that the A3P might have done this.
These motors are bulky and may block star projections if mounted at the top of the supports and would stretch the central core if mounted there.
Also as you progress with changing out the analog motors, I'll be interested to see how you did it to get first hand advice.
Part of this, but off the topic slightly, do you think a timing belt could be twisted a bit so that one pulley could be offset by 23.5 degrees to the other?
It turns out I am having trouble finding a short flexible shaft. By their nature, they can't be too short went bent. A universal joint also takes up more space than I want. If I could afford custom made bevel gears, it would be perfect. Then I thought perhaps a timing belt twisted. What do you think?
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Post by Ron Walker on Aug 24, 2022 11:18:05 GMT -7
Posted by: Ron Walker Nov 12 2007, 01:56 PM QUOTE(charles jones @ Nov 9 2007, 01:36 AM) * Ron, thank you so much for taking the time to photograph all this stuff. It'll help me tremendously in the design of mine. I have also considered the mounting of the motors in the base as you suggested some time ago that the A3P might have done this. These motors are bulky and may block star projections if mounted at the top of the supports and would stretch the central core if mounted there. Also as you progress with changing out the analog motors, I'll be interested to see how you did it to get first hand advice. Part of this, but off the topic slightly, do you think a timing belt could be twisted a bit so that one pulley could be offset by 23.5 degrees to the other? It turns out I am having trouble finding a short flexible shaft. By their nature, they can't be too short went bent. A universal joint also takes up more space than I want. If I could afford custom made bevel gears, it would be perfect. Then I thought perhaps a timing belt twisted. What do you think? You can go around corners with timing belts but you need to use extra timing gears placed at the appropriate angle to do it. Let us say that you wanted to send a drive 90 degrees to another one. Looking from the side we would see the drive edge on and the belt flat to us. We would twist the belt 90 degrees and then go over an idler pulley placed 90 degrees to the drive one. Then the belt world twist back 90 degrees to be at the proper angle to drive the final gear. I hope you can understand what I just said. As I will probably need flexible shafts to drive parts of the Moon projector I have look at these two locations. www.smallparts.com/products/descriptions/FDCC-FDCP.cfmsdp-si.com/eStore/Direct.asp?CP=Index.htmThey are somewhat expensive but should make a hard drive system somewhat easy.
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Post by Ron Walker on Aug 24, 2022 11:18:42 GMT -7
Posted by: Ron Walker Nov 12 2007, 02:23 PM Thanks to Owen, I have a bunch of extremely small hex allen wrenches coming my way. This should do the trick and allow me the final disassembly of the planet analogs. I also have the first order of timing belts and gears in the works. If all works out right, I should have the major mechanical interconnects complete on the projector. I know I will need at least one more order to get the Moon unit connected and that should be the last order if everything works out perfect. Since nothing ever works out perfect for me I guess there will be more then one order. But that's the fun of it, isn't it?
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Post by Ron Walker on Aug 24, 2022 11:19:04 GMT -7
Posted by: Ron Walker Nov 15 2007, 10:32 AM I am repeating this post here because I believe it is information very suitable for this thread.
My first order from Small Parts just arrived and here are the two allen wrenches that are required to take the A3P planet analogue apart.
The wrenches are both English measurements.
0.050" Small Parts number HW-050-05 for a pack of five @ $0.90 0.035" Small Parts number HW-035-05 for a pack of five @ $1.95
I also ordered some brass rod which will be needed for some of the bore adapters that will be needed for the new gearing. I have a first order for timing belts and gears which should be delivered soon and I will be able to move forward with this project.
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Post by Ron Walker on Aug 24, 2022 11:19:30 GMT -7
Posted by: charles jones Jan 7 2008, 02:43 PM Ron, with the holidays out of the way, would you have time to look to see if the specs on the A3P motors are visible.
I believe you said the daily motion motor and latitude motor were both dc variable speed. Do you know the torque rated for each?
Thanks for any info you can provide.
Charles
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Post by Ron Walker on Aug 24, 2022 11:21:40 GMT -7
Posted by: Ron Walker Jan 7 2008, 03:51 PM QUOTE(charles jones @ Jan 7 2008, 02:43 PM) * Ron, with the holidays out of the way, would you have time to look to see if the specs on the A3P motors are visible. I believe you said the daily motion motor and latitude motor were both dc variable speed. Do you know the torque rated for each? Thanks for any info you can provide. Charles Here is a picture of the motor plate for the Daily motor. It is a 1/70 HP 1725 rpm motor with a 18:1 gear reduction producing 96 rpm with 5.4 inch/lbs of torque.
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