- Thu May 20, 2010 7:28 am
#101428
Hi,
I'm making a solar tracker that needs pretty high torque to move the solar panels (I'm estimating 500 Nm of torque to move all 5 arrays that are in a line). I don't need high speed at all, since it's just the sun we're tracking here... but I've been having difficulty figuring out what the cheapest option would be.
1) I initially wanted to just take a hobby servo, attach a geared sprocket, modify for 360 degrees rotation, and attach a gear reducer to it, along with a rotary potentiometer (angle sensor) somehow attached to the shaft/gear. I don't really need the gear to be in-axis with the motor, as I have lots of space. Most of the gearheads I've seen are expensive because they use planetary gears, etc. So I'm having two issues:
- I can't seem to find a large gear on McMaster, and
- I'm not sure how I'm supposed to connect a rotary pot to my gear. Something like a 500:1 gear ratio should do the trick I think
- are these reliable at all?
http://www.pololu.com/catalog/product/69
I've read that worm gears with high gear ratios are ridiculously inefficient (<20%) due to friction...
2) Would a stepper motor be a better option here? I'd still have to use gears, though...
3) If I could somehow turn the panels from the sides, I could just use the mount in the center as a lever, which would require much less torque. But how do I position and attach the motor to be able to do this?
any help much appreciated
thanks!
I'm making a solar tracker that needs pretty high torque to move the solar panels (I'm estimating 500 Nm of torque to move all 5 arrays that are in a line). I don't need high speed at all, since it's just the sun we're tracking here... but I've been having difficulty figuring out what the cheapest option would be.
1) I initially wanted to just take a hobby servo, attach a geared sprocket, modify for 360 degrees rotation, and attach a gear reducer to it, along with a rotary potentiometer (angle sensor) somehow attached to the shaft/gear. I don't really need the gear to be in-axis with the motor, as I have lots of space. Most of the gearheads I've seen are expensive because they use planetary gears, etc. So I'm having two issues:
- I can't seem to find a large gear on McMaster, and
- I'm not sure how I'm supposed to connect a rotary pot to my gear. Something like a 500:1 gear ratio should do the trick I think
- are these reliable at all?
http://www.pololu.com/catalog/product/69
I've read that worm gears with high gear ratios are ridiculously inefficient (<20%) due to friction...
2) Would a stepper motor be a better option here? I'd still have to use gears, though...
3) If I could somehow turn the panels from the sides, I could just use the mount in the center as a lever, which would require much less torque. But how do I position and attach the motor to be able to do this?
any help much appreciated
thanks!