I have three stepper motors that I purchased a few weeks ago for my Solsylva 10x9 build. You can turn the shaft on the motors quite easily when it is not enabled. When they are enabled of course they hold with the motor's holding power. Last night with everything shut down and the driver disconnected I was turning the leadscrews on all of the axes to get them to the middle of travel so I can start setting up a new driver board today. Two of the motors turned fine, but one of them has a resistance that falls somewhere between holding power and free moving. I disconnected the motor and turned the shaft by hand and there is definitely resistance and it feels almost like turning a stuck gear or something.
I sat it down and picked it back up after thinking for a minute and it turned freely. At that point I noticed that it was rotated 180 degrees from how it is mounted. When I turned it back to the way it was mounted, the stiffness returned. I turned it back upside down and rotated the shaft and shook it around some and eventually it got to where it turned freely in the original mount position.
Is this something that is out of the ordinary? It was about 12:30 when last night when I did this so I didn't have a chance to hook it to the driver to see if it spins okay using the driver.
If some of the wires are shorted together, it will be very hard to turn. Make sure that each wire is isolated and then see if it will turn easily.
Mach3 2010 Screenset
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)