I have a project in which I need to infrequently use a servo motor to change the direction. Say once every 1-2 hours on the upper end and 10-25 mins on the lower end. I have seen a lot of posts about the SG90 not being to durable but most of them are in cases where it is under constant operation. How does the durability for the SG90 scale when its making infrequent turns.
My payload is fairly heavy, is there a way I can reduce the speed of rotation to further improve the durability
The durability of the SG90 is more determined by the fragility of it's plastic gears than operating hours. One bump to the servo arm, may cause one tooth, fracturing off of the largest sprocket wheel, disabling the servo.
For little more you can buy all metal gear servo's
You may want to have a look at the Corona CS939MG servo. It has one sprocket wheel more in it's gearbox compared to its 929MG twin brother.
So the 939 is slower, but has more torque. The 929 is faster.
Hey there, thanks a lot for the recommendations. The only problem I'm facing with getting the CS939MG is the cost. I am a student working on a research project while in high school and my known local sellers do not sell the 939MG. Do you know any reputable international sellers that do sell it. Alibaba cannot ship to India, to my knowledge
I am able to get an SG90 for $0.92 (equivalent), the setup I'm working on won't be in particularly rugged conditions however a reasonable amount of durability is something I do care about. (Sorry for not mentioning this in the main post)
Would you be able to give me some advice on ensuring a configuration for decent durability on the SG90s as my budget is greatly limited
Yes it is, a fairly high load, however the servo will be placed close to the center of mass of the load in order to reduce the needed torque. I understand that this isn't the ideal servo or configuration for this however due to my budget I'm trying to find workarounds that can "work"
That's not good because the servo is constantly under stress. The motor has to constantly provide torque, the circuit is constantly drawing a lot of current and getting hot.
So your infrequently is actually more like constant.
I think I may have miscommunicated how this is working? The project is to study the movement and habits of bird species. We are using a servo motor and a rotating parabola mic. The mic (and dish) are perpendicular to the ground, in that case the motor wouldn't have to constantly provide torque as there is no opposing motion after the dish has been turned?
Then a good servo should last forever. The problem the the SG90s is that have been copied and copied and copied and the units you see on alibaba, amazon ebay are just mass produced junk.
There have been several people on the forum complaining about quality. They may buy the ten pack and two may continuously rotate and two may last for a week. Basically you get what you pay for.
I was looking into full metal servo motors. The CS939MG isn't sold by any local sellers however the MG90S mini, TowerPro MG946R are sold. The Pro-Range OT5320M is also sold however is slightly out of my budget range.
Are any of these good substitutes?
I think you missed the point here. There is nothing wrong with the SG90 if it has enough torque for your application and you can verify that it is a genuine TowerPro servo.
Of course a servo with metal gears will last longer that one with plastic gears, so the SG90S would be a good choice if you want a longer operating life. Again you must verify that it's a genuine TowerPro. servo.
The 946 has about 6 times the torque of the 90s so if it's not to costly I would go for it
