Hi. I am looking for a servo with REALLY high torque. Some specific suggestions would be very useful. While I am looking for the highest torque, there are some other requirements.

-it should be under $50-60
-it should have a decent amount of precision (2-3 deg) and at least 180 degrees rotation
-it should not require more than 6A at 12V, less than 6A at 6V would be ideal. 12A at 6V would also be ok but is really not ideal. I have some 6V 6A power supplies that I could connect in series or parallel.
-it should have at least 15 rpm, 30+ would be ideal
-it should not need anything too weird for controlling it
-essentially there should be no other major drawbacks

Also, how many kg/cm is really high torque? Thanks.

 

Also, how many kg/cm is really high torque? Thanks.

Your design process is kind of backwards. Most search tools let us put in how much torque and precision you need and then we press search and it tells us the price. Also, "high" torque is not exactly a design specification.

What are you trying to do?

 

Is this a motion control servo or a RC servo application??
Max.

 

Is this a motion control servo or a RC servo application??
Max.

A 72 w Rudder controller? I need to see that plane!

 

Again TMI!
Max.

 

180° of rotation (30RPM) will only require a Very low wattage motor with a suitable G.B. , if 72w is the output power required.?
Max.

 

Again TMI!
Max.

TMI or NEI?

 

TMI or NEI?

One of these!



Max.

 

One of these!

View attachment 146912

Max.

Now you've done it! Now we have a political thread. We'll never know what kind of a servo the OP has!

 

Also, how many kg/cm is really high torque? Thanks.

42.

Seriously, YOU are the one who should be telling US what you consider "really high" torque, not the other way around. Absent your definition, I'm free to adopt my own, such as the torque generated by a typical main steering gear positioner for large ships, such as one of these (up to 250 Tonne-meters of torque). I assume you don't need quite that much...

 

Sorry if I was unclear. I need a servo for mechanical positioning, not rudder control. I have looked at some of the specs for servos I have worked with for comparison. So could someone suggest some 80+ kg/cm servos? Essentially, I am looking to get the most controllable mechanical power from my 36W power supplies.

P.S. Those 250 ton-meter gear positioners sound nice. How much are they?

 

Well, I once built a servo system using a motor about 6" x 3" to steer an electric golf cart. And I specified another to turn the cutter assembly on a big giant punchpress (actually just a mediumish one - flywheel was about 3 feet in diameter, if I recall) that cut steel pipe to make those zig-zaggy welded steel roof trusses. Either of those would cheerfully wring you like a wet dishrag.

OBW0549 - One of my regrets is that I never got onto one of the ships one of my clients worked on (as rats in the hold). It doesn't have conventional steering gear but several electric thrusters (generated enough electricity on-board to power a third of Scotland). It can turn by pivoting end-for-end around its midpoint and go fast enough to waterski behind. Iirc, it can hold its position within some very small distance (a metre??) in a 90 km/h crosswind. The whole thing is essentially a 300 metre long servo to play out pipe and maintain tension on it. At the time it was the longest ship in the world. Lot of pics on the web: the Solitaire

 

By my calculations, 80Kg.cm torque @ 30rpm amounts to about 12W (hopefully someone will check this), so I'd be looking for a DC gear motor with at least that sort of spec.

 

So could someone suggest some 80+ kg/cm servos?

The most powerful servo I could find online with ≈20 min. of searching is this one, with 500 oz-in (36 kg-cm) of torque. If you really need more than that, I suspect you'll have to roll your own using a suitable gearmotor, position encoder and control circuit.

 

Servo City has Hitec servos with gear reductions that come close: https://www.servocity.com/bm-785hb-servo-gearbox
Note, the HS785 is capable of multiple rotations. To attain 80 kg-cm torque, rotation speed will be reduced. Look at the values for 6 volts.

 

So we ARE talking RC type servo's as opposed to typical motion control versions!
Max.

 

So we ARE talking RC type servo's as opposed to typical motion control versions!
Max.

That was not the OP - so I am still not sure what he is talking about.