Actuators AGAIN ...

[Archived-1]

I will never buy another from a sat shop, this is the way I will go and modify it .

http://www.techdrives.co.uk/acme-thread-actuators-350kn.html

 

[Vipersan]

I will never buy another from a sat shop, this is the way I will go and modify it .

http://www.techdrives.co.uk/acme-thread-actuators-350kn.html

Fair enough Martin ...
..but it does beg the question ..
Why can't manufactures provide quality products to the Sat comunity if such tech already exists
?
They cannot say there is no market for it...and not everyone has the ability to mod..
rgds
Evan

 

[Archived-1]

Fair enough Martin ...
..but it does beg the question ..
Why can't manufactures provide quality products to the Sat comunity if such tech already exists
?
They cannot say there is no market for it...and not everyone has the ability to mod..
rgds
Evan

I am unsure TBH Evan, maybe the product we need in this instance is out there for us, and we are looking in the wrong place, sat shops.

 

[Vipersan]

I am unsure TBH Evan, maybe the product we need in this instance is out there for us, and we are looking in the wrong place, sat shops.

Keep looking buddy and post any findings here ..

 

[Archived-1]

Some good reading in that link about them, they do come with certain accuracy from one to another,

The anti-turn option is used in cases where the load to be moved is capable of rotation. In such cases the screw and load will spin without axial movement unless the anti-turn device, which is a keyway in the protective tube, is chosen.


Bellows can provided for both designs when used in particularly difficult environments. Acme screw jack catalogue pages 40 and 74.


Higher levels of safety can be integrated. For both designs a safety nut is available. This is a back-up feature that prevents the load dropping in an uncontrolled manner in the event of thread breakage due to overload or wear. The safety nut works in one direction only. Catalogue pages 42 and 76. Also the wear can be monitored using a thread wear option which gives a limit switch output when a set level is exceeded, catalogue pages 43 and 77.


For applications that require a high level of positioning accuracy, both designs of screw jack can be provided with an adjustable backlash feature, catalogue page 46.

Edit

(Easy to get from 36v to 24V and put a different stoke in it to compensate )




http://www.techdrives.co.uk/products/screw-jacks-faqs.html#what-is-the-efficiency-of-screw-jacks

 

[Vipersan]

Some good reading in that link about them, they do come with certain accuracy from one to another,

The anti-turn option is used in cases where the load to be moved is capable of rotation. In such cases the screw and load will spin without axial movement unless the anti-turn device, which is a keyway in the protective tube, is chosen.


Bellows can provided for both designs when used in particularly difficult environments. Acme screw jack catalogue pages 40 and 74.


Higher levels of safety can be integrated. For both designs a safety nut is available. This is a back-up feature that prevents the load dropping in an uncontrolled manner in the event of thread breakage due to overload or wear. The safety nut works in one direction only. Catalogue pages 42 and 76. Also the wear can be monitored using a thread wear option which gives a limit switch output when a set level is exceeded, catalogue pages 43 and 77.


For applications that require a high level of positioning accuracy, both designs of screw jack can be provided with an adjustable backlash feature, catalogue page 46.

Edit

(Easy to get from 36v to 24V and put a different stoke in it to compensate )




http://www.techdrives.co.uk/products/screw-jacks-faqs.html#what-is-the-efficiency-of-screw-jacks

Ah yes ...but not so easy to accomodate 24v with a standard V or G box ..
The command being dropped automatically on a timed out basis as I well know ..
If the destination is not reached within a fixed timed limit the dish would go sailing on past the target as I found out the hard way....
24v is not enough voltage to drive across the arc quickly enough..
You'd need to design your own Vbox to drive it to fixed positions at a slower speed.
;)

 

[Archived-1]

Just put a reducer inline and put a different stroke in the actuator to compensate, easy enough to do.

 

[Vipersan]

Just put a reducer inline and put a different stroke in the actuator to compensate, easy enough to do.

By different stroke I assume you mean changing the thread pitch to cross the arc more quickly ...?
Would you then not lose accuracy ?

If on the other hand you mean chaging the stroke length by using a shorter length jack ...then to traverse the same arc the anchor points would have to be shifted ...
Not always possible ..and certainly not on my mount it isn't ..
I've tried all manor of chaged anchor points and only using a 24 inch or longer jack can I get from say 60E to say 60W ..
an 18 inch actuator would greatly reduce my arc..

 

[Archived-1]

Not with a good quality actuator, and really no need to change it if you don't mind waiting a little longer to move from one position to another, in the link it tells you about different accuracy, ranging from 1 to 4 I think I read.

 

[Vipersan]

Not with a good quality actuator, and really no need to change it if you don't mind waiting a little longer to move from one position to another, in the link it tells you about different accuracy, ranging from 1 to 4 I think I read.

But there's the rub buddy ..
I dont mind waiting longer at all ...
but the Vbox does and times out ...
If I remember correctly ...at 24v the accuracy improves and yes it takes longer to traverse the arc but selecting say 1W from a start point of 58W ...the Vbox will time out before reaching 1W and drop the command ...
The motor still receiving 24v will continue on oblivious of this ..and pass 1W having lost the command it wont stop ...and will continue on its way to the East Limit

 

[Archived-1]

Don't attempt it then pal, but I will be doing it, and I am sure it will work from the messing about I did with the chain driven rotator and V box

 

[Vipersan]

Don't attempt it then pal, but I will be doing it, and I am sure it will work from the messing about I did with the chain driven rotator and V box

I certainly wish you luck buddy ...but do keep in mind what I said IF you use a conventional positioner to drive it ..at 24v
Roughly 60 seconds is all you get from command issue to target reached ..
any longer and the initial command is deleted by the Vbox firmware ..
best o luck..

 

[Archived-1]

Ive just tested the V box, no problem with it going slow but thanks for the tip and luck

 

[Vipersan]

Ive just tested the V box, no problem with it going slow but thanks for the tip and luck

Sorry Martin ..Not quite following that ..
??
Do you mean you have a Vbox already powering an actuator at 24v ?
rgds
VS

 

[Archived-1]

Yes unless my meter is faulty but it certainly went slow.

 

[Vipersan]

Ahh so you are stepping down the voltage on the mains side ...pre transformer ...
Now I get it ..
;)
So did you then try driving across the arc from limit to limit ..
We know this will run slow now ..
Did you then try moving from a fixed position to another moving across a section of arc greater than 45 degess ? ..and if so did it stop at the selected point ?
Then try the same with greater arc coverage ..greater than 45 degrees ..
The last point is how long is the actuator in question ?
This depending on the anchor points is also relevant to the amount of arc covered in a specific period of time ..
All setups are different ...but my experiences indicate the timeout is roughly 60 seconds which at 24v on my system will cover about 40 degrees ..
Time to go for now ..
supper time ..then outside to stare at the sky for a few hours ..
Totally clear here ...so fingers crossed for the perseids.

 

[Archived-1]

I've no need to do that Evan I will take you at your word if it becomes a problem I will just locate the time sensor and turn it up if that's not possible I will replace it for one that's variable, anyway this will be as and when I have lots of thing to do before I will be doing this I will show you once I start in in the mean time I will leave it at that

 

[Vipersan]

I've no need to do that Evan I will take you at your word if it becomes a problem I will just locate the time sensor and turn it up if that's not possible I will replace it for one that's variable, anyway this will be as and when I have lots of thing to do before I will be doing this I will show you once I start in in the mean time I will leave it at that

Not a component as such ..
More like a timer loop in the firmware ..thus totally internal within the custom processors programming ...so it isn't something easily modified sadly ..
or ..I would have done it by now..
rgds
Evan

 

[Archived-1]

I will sort it leave it with me ☺

 

[BM300]

Very intresting reading friends.

Have you tried the THOMSON SAGINAW brand?
It was a haveavy and rubust.
I do not kbow if it is still manyfactured.

I saw picture of a dish with 2 actutors driving the dish, one on each side of the back ring. when one was extending, the 2nd one was retracting.
I think they were wired in reverse!
(It is an idea but how practical? I do not know)

I have not tried this but used a counter-weight instead.
The motor lives longer with less strain on it at the extreme East and West.