elti:
@nilton61 - why would you need an AC source and a rectifier + capacitor? Why won't a DC source do?
How did you calculate the 30-35V value?
Pure DC sources are batteries and DC generators. When it comes to generating DC from the mains voltage (which is AC) you will have to choose between a traditional transformer followed by a rectifier a resevroir cap and an optional regulator on one hand and a switching adapter on the other. Most DC adapters that you buy today are regulated, this is because for most uses they have a good cost/performance ratio because regulating the voltage diminishes the need for costly reservoir caps.
But for this application large caps are exactly what we are after and there is no need to regulate since the driver already regulates the current. The BED has a maximum voltage of 35V you should be as close to this as possible. If you rectify the voltage from a (easily available) 24V transformer you will get sqrt(2)*24V= 34V subtract two diode voltage drop of 0,6V and you get about 32,8 wich is exactly right.
When looking at this guys project, he only chose a 18Ncm motor, significantly lower than 50Ncm, how come?
http://www.pocketslider.de/DIY_slider_en.html
As far as i can see he uses a DC gearmotor with a stall torque of 6,48 Nm. That's a lot. In addition to that it look like he is using a 10 tooth Module 1 pinion. This will have a pitch radius of 5mm. The force will be 136N. Using A DC motors means having a higher torque but no means of controlling the distance traveled, unless using a encoder and some quite advanced code to control motion. Also the desing seems to me to be used for horizontal travel, not vertical as you specified.
Note that I want to make it a Move-Shoot-Move mode, so I want to be able to move the motor in smaller steps (this is in regards to your first message).
When you use the BED or similar you will get 3200 steps/revolution. With a 12 tooth XL pulley that will give you 0,019mm/stepwich is good enough for light CNC and 3d print work, i bet it will suffice for photography.
Do you have a better, rather affordable, motor to suggest? I really am clueless about this and learning a lot from you. So thank you very much!
The motor parameters for your project depend on a number of parameters:
- Power, that is the product of torque and speed. You have only specified the force for linear motion, not the speed. I suppose speed need are not that high.
- Precision of control
- System complexity (that includes your ability to handle that complexity). Stepper motors are a good tradeof between the two previous points
- Sourcing, the components have to be available in your part of the world with reasonable deliverance times and costs