Quote:
Originally Posted by AstroJunk
The ZWO uses stepper motors rather than servos like others. Stepper motors lock without power - it's actually quite hard but not impossible to move them. The break on power failure for the RA drive suggests that 13+ kg without counterweights is sufficient to overcome the natural resistance to movement!
Looking forward to some real world reviews!
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That is actually not quite the case. Most stepper motors will have an amount of "Detent" torque, which is the amount of torque required to move then when they are unpowered, it is generally not a huge figure. If you take a typical small stepper you will rotate it pretty easily by hand with "Cogging" felt at each point the motor would stop. When they are powered but not being stepped they then produce "Holding" torque, proportional to the current supplied.
This page has a good write up.
https://www.motioncontroltips.com/fa...olding-torque/