[jvangelder]

Does such a thing exist? I only need approx 1deg accuracy, no more than 180deg of rotation, 3-12vdc operation and a simple 3 wire hookup like a normal hobbie servo. I dont need encoder feedback, temp, etc.

Also i only need around 150 in/ft of tq peak,

Ive seen the pololu units and they are far far more powerfull than i need, and a bit more than im looking to spend.

Something in the neighborliness of 100-125usd would be ideal as it would keep my overall costs in check

-Jacob

[mike_Kilroy]

ur post to me is a oxymoron..... u want industrial version of a hobby servo system but then list $ 100 cost....... your units make no sense on the torque rating of course - typo I assume.... u prob meant 150 #-in torque.... so a truly industrial 150#-in (12.5 #-ft) continuous torque industrial motor and drive and cable set like Kollmorgen AKM52/AKD12amp drive is around $ 2000.00

Your $ 100 range for an industrial servo motor, drive, and cable set is off by more than a order of magnitude.

What is it u want the "industrial" version do that the hobby version does not? be capable of running 1 rev per hour smoothly? position repeatably to 1 part out of 3,000,000 per revolution? run to 8000rpm max speed too? be able to go from point a to point b by a single digital input? Have less than 2% torque ripple Hold speed commanded to withing 0.1%?? control torque limits to 10%? Have a 1/2 dozen uncommitted inputs, some outputs for programmability? accept any type feedback like resolver, encoder, sine encoder, halls, do wake & shake if needed? be able to link upto 125 eeprom stored steps into a 'program' started with a simple digital input? give analog speed and load meter outputs? Have MTBF of over 20,000 hours? Have UL listing & CE listing for Europe? much more If u answere yes to a lot of these then you are in the industrial servo area and cost is not $ 100.

[Al_The_Man]

Does such a thing exist? I only need approx 1deg accuracy, no more than 180deg of rotation, 3-12vdc operation and a simple 3 wire hookup like a normal hobbie servo. I dont need encoder feedback, temp, etc.

-Jacob

Servo? position to 1deg? no encoder?

Sounds like you need a stepper, .9deg 1/2 step.

Also i only need around 150 in/ft of tq peak,

in/ft????

Al.

[LN-JET]

These guys are obviously not into the rc kind of servos.
I am under the impression that when the "industry" need a servo of that type, the use any good quality servo from Futaba or JR. $100 will barely get you better stuff.
Seiko has a range of servos, but they typically start in the 1000 oz/in range.

Lars

[jvangelder]

ur post to me is a oxymoron..... u want industrial version of a hobby servo system but then list $ 100 cost.......

Allow me to clear this up,

Im looking for 150 oz/in of tq continuous, nothing that is out of the realm of a hobby RC servo that you would find in an RC airplane. However, i want something that will allow 50,000 repetitious movements from anywhere within its 180* allowable movement, a day, 7 days a week, for years. The total degree of movements will vary alot, possibly every few min, i cannot say as the range, and rate of movements is dependent on things that cannot be predicted. IE the servo might be moving from 15deg to 25deg for a few min, soon there after might be going from 50deg to 90, etc

MTBF of 5k @ whatever the units 100% duty would be nice, more would be better.

my bad on the in/ft of tq, that was an dumb-ass typo on my part

I do _not_ need load outputs, unit temp, pos error or anything of the sorts.

Id like around 1deg of accuracy, however if something is in the realm cost wise id budge if it was worth it.

I am not looking for a servo motor as in something you would use in a normal industrial motion setup, they are way overkill, un-nessesary and wouldn't make the whole unit worth while cost wise. I have a pile of baldor motors and amps and wont use any of them on this, my glenteck amps are larger than the proposed unit im trying to source

Thank you for the help

-Jacob

[jvangelder]

These guys are obviously not into the rc kind of servos.
I am under the impression that when the "industry" need a servo of that type, the use any good quality servo from Futaba or JR. $100 will barely get you better stuff.
Seiko has a range of servos, but they typically start in the 1000 oz/in range.

Lars

I haven't ruled out some of the better hobby servos, i was just curious if a non-hobby line exisisted.
-Jacob

[Al_The_Man]

So as I see it you want high quality with RC prices?
What rules the stepper out?
They have been used for many years in commercial applications in assembly line use etc.
Al.

[jvangelder]

I'm looking for the high-quality version of the plane-jane $15 hobby servo as far as reliability goes.

i don't need brute strength, in fact i really don't need much strength at all. i just don't want shafts wearing though plastic bushings, and cast cheap plastic teeth slowly turning themself into something resembling chewing gum.

Im avoiding steppers because id have to gear them down to avoid stalling them, unless a stepper can turn 0.25rpm and reverse at 0.1rpm, reverse again and go .5rpm etc. gearing them down would take more more space, unless i used a stepper motor the size of a hobby servo motor... which kind of defeats the point, unless i could just manufacture my own servos for around 100

-Jacob

[Al_The_Man]

A a general rule, steppers have more torque than a servo for a given OA frame size.
A stepper can turn and operate in one step increments, as slow as commanded?
If using in half step mode then 1 step would be .9°, full step 1.8°.
If turning at a very low rpm, then the rated voltage of the stepper could be used, as the maximum torque is at 0rpm.
If you don't need much torque then why the need to gear down?
Al.

[kreutz]

Hobby type servos use a potentiometer as positioning feedback, it qualifies as encoder.

Best regards,

kreutz

[kreutz]

Im avoiding steppers because id have to gear them down to avoid stalling them, unless a stepper can turn 0.25rpm and reverse at 0.1rpm, reverse again and go .5rpm etc. gearing them down would take more more space....-Jacob

Look at the following video, such steppers are doable (DIY)

[ame=http://www.youtube.com/watch?v=prsGonvYwNY]Mardus Kreutz Test # 2 - YouTube[/ame]

kreutz

[mike_Kilroy]

I too agree that what u should consider is a stepper motor for $ 35 and stepper driver for $ 75. shold do all you are asking for and then some.