Interesting,
but I already have the motors, and the gears are on their way. What
I was really looking for is how to drive the stepper-drivers, he DM542
series ones.
Ron
On 7/13/20 7:53 PM, cogoman via Emc-users wrote:
I recently discovered geared stepper motors.
http://www.zyltech.com/nema-17-stepper-motor-geared-planetary-gearbox-1-7-a-3-1-nm-435-ozin/
I've been happy with zyltech in the past. I bought one of these for
evluation, but the specs seem to be great for CNC. Low enough current
to work with a stepstick, High enough torque for a fairly powerful
machine, and less than 4 mH inductance should let it step pretty fast.
5.18:1 gear ratio should reduce that 4 meter spur gear, but the link
below has higher gear ratios that would reduce that spur gear greatly!
Backlash could be a problem for CNC, but if you are only going one
way, the less precision gearboxes might be fine.
https://www.omc-stepperonline.com/geared-stepper-motor/?sort=p.price&order=ASC
Once you visit the stepperonline web page you know as much about them
as I do, but their offerings might be just right for your application.
On 7/9/20 2:23 PM, R C wrote:
Hello,
this is (probably) off topic, been seen that happen. If it is please
ignore it.
I am building a "motorized" telescope mount (dobsonian) with what is
called an equatorial platform, it has 3 axis which I am going to
drive with stepper motors.
The stepper motors I use with a stepper driver, those common DM542
ones, the stepper motors themselves are 2A and 1.8 degrees per step.
What I want to accomplish with the equatorial platform) (it
compensates for the rotation of the earth) is that, the start and
end position accuracy is not that important, smooth and
constant/consistent movement is. for the azimuth/altitude precision
is not a really big deal, but you'd want to move these 2 axis
somewhat swift.
So there are a few factors to decide.
I probably want micro stepping, what settings on the driver for
pulses per rev, is best to use (or is that just trial and error?)
As with PWM itself, I am probably just not too familiar with it. From
what I understand, the voltage I use for the motors determines how
fast I can go (I am going to use a 48V switching power supply).
as for PWM, I can of course change the length of the pulse itself
and, independently, change the time between two pulses. What is the
relation ship there? WHat does a longer width of the pulse itself
do? and what exactly does a longer gap between the pulses do (of
course the wider the gap between two pulses the slower the motor turns).
for, especially, the equatorial platform, I want to avoid "jerking"
it, meaning starting and stopping the stepper motor as little as
possible and just go at a 'slow' constant speed.
sorry if totally of topic....
thanks,
Ron
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