Strong winds strip actuator

My actuator went fubar a long time ago, and I cant find parts for it, (OEM channel master, wheel cog for the reed switch) so all I did was move it tot the satellite with the HD NASA channel on it and fixed it in place, this until I find a replacement actuator that wont cut too deep into my budget.
 
First attempt at magnet wheel pic below. Magnets are pressed into tight holes in middle plexiglass sheet. Thin plexiglass sheet is glued on each side. (Magnets entrapped) It may not show well in photo, but magnets are NOT perfectly spaced apart. Drill creep thru off the alignment.

I know I could just mount it to test. BUT, the wheel needs to be glued onto an optical disk. Be a PITA to glue it on, then have to remove it. Any ideas if this will be usable as is, or should I attempt to make another wheel with better spacing to begin with?

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Any micro cracking shouldn't be an issue since three plexi sheets are glued together. (Many are heavy sanding scratches for a good bond, not cracks)
 
What you have to me looks good. Probably cannot do much better unless you get into a place that has equipment to make this stuff. Another thing to consider is whatever you do will probably be wrong. If you don't mount it, then you should have, and if you do mount it then you should not have.

My opinion is you should mount what you have already assembled and see how it does or does not work. It might work fine like it is for what you need it to do.


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My first actuator had magnets that alternated polarity N then S, N then S, etc. on the wheel. The sensor screwed into a white plastic mount so that it could be adjusted in or out to miss the rotating wheel. The sensor failed and I replaced it with a reed switch in a glass tube by soldering #14 copper wire to each end. The wire was stiff enough to hold it all in place. Worked fine but my count doubled which was an added benefit for Ku. I guess back then the magnet would either pull on the internal workings of the switch then push it out assuring full motion of the switch.
 
After thinking some more: I can temporarily mount this with a hot glue gun. Center only. Shouldn't be too hard to remove if necessary.

First; I'd like to rig up a AAA battery and light bulb circuit to determine the distance to mount the sensor. Visualize what is going on since I don't have high-tech test equipment. I will have to build a sensor mount from scratch. (Maybe make it adjustable) I believe these little magnets are too strong, but embedding them in the plexiglass will lessen their strength. Plus the magnets will never drop off.

I plan to bring actuator inside the house to do the testing. Weather too unreliable to do much outdoors.
 
clucas said:
My first actuator had magnets that alternated polarity N then S, N then S, etc. on the wheel. The sensor screwed into a white plastic mount so that it could be adjusted in or out to miss the rotating wheel. The sensor failed and I replaced it with a reed switch in a glass tube by soldering #14 copper wire to each end. The wire was stiff enough to hold it all in place. Worked fine but my count doubled which was an added benefit for Ku. I guess back then the magnet would either pull on the internal workings of the switch then push it out assuring full motion of the switch.
Click to expand...

One of these actuators had a 4 magnet wheel, but NO sensor or bracket. Not sure how the magnets were orientated since they jumped out of place when I removed it from the shaft. Magnets are large in diameter and I don't believe they would function with the double count switch I bought.

I could have tried a single count switch with this magnet wheel.... but didn't want to be limited to only a four count wheel. If my homemade wheels don't work, it may be a fallback option. (Or I could remove the large magnets and glue my small magnets in their place, and use a new double count sensor.)

Time will tell.
 
Glad to hear a little crafty experimentation is happening. Can I help keep the head banging down a little?
From #26. And from what clucas stated. Once you understand a few thing that I found out over time, hopefully building your own encoder wheel might help you get it working faster and better.

Clucas stated that he converted from a Hall sensor to a reed switch. And his counts doubled. Understandable.
Reed switches for the most part just need a magnet close to them to open/close the "contacts".
Because his counts did double, that leads to understanding the basic hall sensor types. More on that in a minute.

Your older magnet wheel encoders most probably used ceramic magnets. My dive into making a wheel sent me to buying a stack of 4mm diameter neodymiums.
I used an old Houston Tracker hall sensor from and old (I think) Saginaw actuator and mounted it in a Superjack.
The wheel was just big enough to clear the inner workings of the original 6 pole ceramic disc magnet.
I used 20 magnets super glued evenly around the inside diameter of the disc. Used a sharpie to mark the side on them that was the same polarity. So all black sides faced up.
Here's where I lucked out. More on that soon.
All put together and the magnet wheel mounted to the actuator shaft gear shaft in place of the original magnet. Time to position it.
I wired everything on my bench. Gave the Hall sensor 5 VDC. Powered the actuator with my 12 VDC Harley battery.

Hooked my oscilloscope to the Hall sensor output lead an ground. Powered the actuator. Quickly found out that the Hall sensor was an 'open collector' output.
So put 5 VDC in series with the output terminal and ground lead of the sensor. If you have an actuator controller with reed switch sensor inputs, you should be able to measure DC voltage at those pins. Oscilloscopes aren't good at all measuring switch closures/resistance. They are voltage/time.

Alrightey. Next I positioned the hall sensor module close to the magnet wheel until I got a nice square wave. A bit....not perfect....some pulses were wider than others. "Design error" in spacing the magnets equally? Yeah that's the ticket. Somewhat. Once satisfied with the positioning of the sensor. I marked and drilled slotted holes (for wiggle room) in the gear cover plate and and mounted the sensor. More on that too.....

Let's call this part one.

Hall sensors come in several types. Some detect magnetic strength. Imagine being able to turn radio volume up by putting a magnet closer to the volume control. Or turning it down by pulling it away. Proximity. Not what we want. We need snap action like a toggle switch.
Some turn on and off when a magnet is brought close. No matter if the N or S pole is used. They get a magnetic field strong enough, they turn on. Pull it away, they turn off. We can use those types.
Some turn on when the N pole is brought close to them and turn off when the S pole is close. Meaning you could turn one on and take the magnet away....Hall would still stay on as long as it had power on the voltage supply. When you brought the S pole close, it turns off and stays that way. Most probable the type that was originally in clucas' unit.

So. If we want to build a Hall sensor encoder. A unipolar (magnet close, no matter which pole, turns on. Pull away, turns off) or a bipolar (turns on when one pole is brought close, and is forced off when the opposite pole is present). Those are the types needed.
Most all modern Hall switches have a Schmitt trigger output. Also very important. Gives a fast and positive action. Think of a snap action Lutron wall switch that clicks versus a Decora that "kind of" does.

Coffee, chores, more on this.
 
Any ideas how to set the Limits on this Uniden actuator? (Von Weise) I'm not familiar with this type. I see where it can be set... but that looks to me like it will only work for one direction. Or am I missing something? If only one limit... I will set it for maximum safe extension. *Picture taken before reed switch conversion

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Actuator has been briefly tested OFF the dish. Counts are flying in both directions, so it should give many counts between Sats. How accurate/precise it will be remains to be seen. Hope to install it tomorrow if everything goes as planned.

Thanks for all assistance!
 
Pretty easy. The stacked microswitches and cams control the limits. From the factory the lower limit is usually already set. That's the lower cam. It's non-adjustable (unless you loosen the geartrain cover plate to disengage the gear that drives the cam). So from the factory the actuator tube is retracted all the way in (shortest) and then turned out several turns. I choose 6 full turns when setting mine up.
The upper cam is for the extended limit. Loosening the top 2 screws and lifting the cam and turning it to adjust the upper limit. Then engaging the stepped cam coupling to the lower cam and tightening the screws. You adjust it so that the upper microswitch 'just' clicks.
Of course you need to be aware of which way the cam turns when it extends/retracts.

There are cases like when you remove the gear drive from the tube that the lower limit cam will get off kilter.
Just unbolt the motor from the tube. Drive the motor to it's lower electrical limit until it shuts off. Retract the tube with a pair of Vice Grips. Spin it out, oh let's say 6 turns. And reinstall the motor.
Then you will want to verify that the upper limit is still set right.

There will be some times that the limit cams "jump right past" the microswitch and the motor keeps running. Like if a switch gets dirty or is failing, the plunger is worn.
You could get fooled and flustered because what seems to be is totally "off". Because the cam needs to rotate to the opposite side of the switch plunger. That's where loosening the gearcase cover and turning the cam gear would be needed.
 
Thanks Arlo!
After looking at it better with my glasses on today I 'discovered' that lower limit. :rolleyes: And yes, it was preset for the retraction. I adjusted the upper limit with plenty of margin for error. Will determine exactly where it needs to be later.

Actuator is mounted!
On the west side and pushing up as previous one. (This dish only needs to cover the western arc) Sats are programmed in from 135w to 116w so far. Done messing with it today. Mama wants her PanAmericana NOW!. lol

135w to 116w = 19 degrees.
135w to 116w = 291 counts
15.3 counts per degree Which is higher count # than I ever had before.

I will need to slide the actuator down at the clamp 2 or 3 inches to maximize the throw. Ran out of daylight today. Finished wiring the motor wires using the cellphone light.

Whether the count positions remain accurate over time remains to be seen.

:churn::yes1::agree::talk015:
 
I get about 446 counts from 135w to 117w. It helps to have a few more counts to align the dish better. I think a bigger dish will have more counts than a smaller dish if everything else is equal except for dish size. My experience with old actuators is they have inconsistent counts at least part of the time. Positioner setup has been modified some in TNAP images to make it more useful for dish alignment and calibrating c band actuators.

Regardless of what the counts are, you got the dish moving again without spending hundreds of dollars. I call that a Success any day of the week. Congratulations!
 
Awesome!
I have my 'cheat sheet' in a ring binder. Across the arc you find that sections of it need more or less pulses to travel so many degrees.
So even though I have some 40 sats located and stored already. I know that for...lets say 0 is my starting point for 127W. For easy resynching of the ASC-1 when things get out of whack.
From 127-125 I get 125 encoder pulses. Or right at 62-63 pulses/degree (don't know how to do the little degree character).
As I extend the actuator from 113 to 111. I get 142 pulses. Or 71/degree. Then 101-99.2 turns out to be 129 pulses. Or around 65/degree.

I have a 36" tube. It lets me cover 131W (damned trees) out to 40.5. Everything from zenith. Or let's say around 81W out to Britain. Counts get a bit freaky due to the actuator to dish mounting geometry.
So 58-55 turns out to be 66 pulses. 22 pulses per degree.
All of those stats are logged in my book-o-notes.
Since I scanned in all C band sats first and my ku lnbf is offset by 6 degrees from dish center. And my channel list is divided by C band first and then ku band. To keep the dish from swinging all over the place when peeking around. Interpolating where a sat 'should be' is a lot easier.

I have as many sats scanned and stored as I was able to. Even if they don't have viewable channels. Because sometimes they do have wild feeds. And transponders are added and deleted on a whim.
I just don't know how those dudes actully do discover wild feeds. If they sit there scanning the arc and scanning every single satellite looking for periodic channels, a newscaster picking his nose in dead air. I don't know.
 
Slid the actuator UP about 1.5 inches today. (Believe I mistyped that it needed to slide DOWN in previous post) From 135w to 87w = 787 counts. Averaging 16.3 counts per degree. Counts increasing as it gets closer to zenith.

I may build an 8 magnet wheel for the other Uniden actuator instead of a 6. Not sure how that will work with magnets spaced closer together. No rush to get this other one done since it will be a spare.

Taking these actuator arms apart were MUCH easier than the SuperJacks! Remove the 3 screws connecting the arm to the motor, then the acme screw just screws all the way out.

The acme screw and arm had some dry rust and old grease powder. I wire brushed the acme screw pretty well and applied some rust remover. Greased it all up with some gear oil and a small dab of bearing grease. (All I had handy) Seems to ruin nice and smooth now. I need to add a grease fitting to the arm later. An accordion boot would be good as well.

Time to watch tv! :talk015:
 
I didn't get to add to my previous encoder rant. But briefly. You have to beware of neodymium magnets and spacing them closer to try and get a higher resolution.
The magnets are so strong and if you don't allow adequate spacing between them, the flux will overlap and the sensor will see it as one continuous field.
The idea is to get as much spacing as you can. If you have the room inside the motor to build a bigger wheel, you should.
And I mentioned I had started out with a certain size of magnet. I ended up getting the smallest ones. I think 2mm. You need that tight rise and fall of magnetic field.
Not so bad at slow speeds. Like when I bench tested mine with a 'scope. But once it was up to full speed on ASC-1 voltage. I started getting errors that didn't show at the slower speed.
And I used a hall sensor at first. A reed switch on high resolution was a no-go. The hall was very high speed with Schmitt trigger.
But still.....

Next. You really should check each and every magnet you use for equal strength. That was one of my issues. It took a bit to figure out.
Even with a precision divided encoder wheel. I was getting long and short pulses. It kind of flustered me.
I took the wheel out of the motor and benched it. Put it on a piece of wood with a hole drilled for a machine screw for a pivot.
"Borrowed" a sewing needle and thread. Taped the thread to the board at a distance where one of the magnets passing it would attract it.
Sure enough. Some magnets would lift the needle and attract it pretty good. Others didn't so much.
So. Hand select them for equal strength. And mark one side with a sharpie so you know what pole is what.

I have 3 incantations of magnet wheels. I'll dig those up and put up a few pics.
Two use 2mm disc magnets and one uses bar magnets.
Hall sensors have a window defined on them. That's in the data sheet for them. The 2 wheels using disc magnets should have been built with the discs around the perimeter of the wheel.
If you search for the key words 'neodyumium disc magnet flux characteristics' or something like that. You will see why.
Placement of the sensor. Whether hall or reed switch is a bit critical. Too high of a resolution on a small wheel with closely spaced magnets, for me, was just very inconsistent.
And. With closely spaced magnets. And many of them on a small wheel.
Actuator controls like the ASC-1 stop counting as soon as the relays in them deactivate. If you spun just the encoder wheel, the ASC-1 wouldn't care
Just a small motor coast will add up in errors. My 'scope has a pulse counter function. Compared to the ASC-1 and it hooked up at the sensor port. In a very short while with the actuator inside on my bench.
"Bumping" it like you would when peaking signals before saving the position. Added up 1, 2, 4 count discrepancies in a very short while.
The 'scope was always spot on. Because it has to be.
A dynamic brake consisting of that 24 VDC mini PCB mount relay with the center (relay armature) contacts out to the limit switch/motor. And the NC contacts having a .22 ohm resistor soldered to them.
With the ASC-1 motor wires connected to the NO contacts. All fitted inside the motor housing cover. Count errors reduced drastically. Not 100% when bumping the actuator E-W, W-E. But very very much better when just sending out a go-to from the receiver.

Enough. Merry Christmas!!
But. I'm going to turn you on to an optical encoder. Almost as easy as making a magnet wheel. Not one bit of tweaking for the sweet spot like for your reed/hall switch.
Just make sure the wheel slots are as accurate as you can make them. Assure that the thru beam is positioned so it either passes light or is blocked by the wheel slots.
And hope a spider doesn't decide to set up home on it. It's THAT good!
 
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Well it may not be pretty...

Fin_Actuator.webp

Multiple layers of plexiglass stacked to mount the reed sensor. Reed sensor was crazy glued on lightly and tested. After it seemed to function ok, I epoxied the heck out of the whole sensor mount platform.

New magnet wheel epoxied to (trimmed down) optical wheel. Magnet wheel was a press fit, but I epoxied the center to the shaft for good measure.

I opted for strength over 'pretty' when it came to the epoxy job. I'll need to do fancier work if I open up a magnet wheel replacement factory. lol
 
IMO, that magnet wheel should be left alone providing you have enough counts to accurately adjust the dish.

Coasting or improper counts are common actuator problems. A given actuator can only produce a certain amount of counts until you start having problems in other areas. Industrial actuators may have internal mechanical brakes which would provide a higher degree of accuracy. I think any actuator builder would tell you that actuators will have a certain amount of coast in them. If the counts get added into the coast, then there will be alignment problems. So if the dish is align-able with a decent degree of accuracy, then leave everything alone and enjoy it!
 
el bandido said:
IMO, that magnet wheel should be left alone providing you have enough counts to accurately adjust the dish.

Coasting or improper counts are common actuator problems. A given actuator can only produce a certain amount of counts until you start having problems in other areas. Industrial actuators may have internal mechanical brakes which would provide a higher degree of accuracy. I think any actuator builder would tell you that actuators will have a certain amount of coast in them. If the counts get added into the coast, then there will be alignment problems. So if the dish is align-able with a decent degree of accuracy, then leave everything alone and enjoy it!
Click to expand...

I don't plan to 'fix it' as long as it works. Besides, we need this up and running... not on the repair bench.

I may experiment with an 8 count magnet wheel on the other actuator though. I'd also like to be able to adjust the sensor height and the in/out direction.
 
Just an update:
After 17 months, my 'temporary' experiment with the homemade magnet wheel is still going strong.... knock on wood. Seems like the temp test can be ruled a success lol
 
Stickin' with the optical. All winter long and not a single fart. Thing is. Too many triggers/rev. and you get cumulative errors from Slight (EB) armature coast down.
Wa-la! Add a DPDT relay to act as a dynamic brake. Stops it like putting Brembos on a fire-chicken.
.....now. about that bouquet channel listing always being in alphabetical order in v6.



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