I want to raise and lower a 10lb weight using a motor and lead screw. The motor would turn the lead screw which would raise an arm up vertically (like a scissor jack).
90% of the time, the weight will need to be elevated in a static position. I'm trying to use the least amount of power as possible, so ideally I'd like to cut off power to the motor when not being used to lift/lower.
I keep reading though that some motors "may cause gear damage when stalled". My three questions are
Is it feasible to cut off power to the motor and expect the weight to stay up?
Would stalling out the motor in the link cause damage to the gears?
Why would stalling out the motor cause damage to the gears? Is it because the gears would rotate without power which could cause issues?
I'm not sure you have understood what "stalling" means. A motor is stalled when it has power but something is physically preventing it from moving. That is when it takes maximum current and can be damaged.
Whether that motor is adequate or the weight will stay up with the motor unpowered will depend on exactly how the mechanism is designed. Scissor jacks definitely stay in place with no-one holding the handle. But how similar is your design?
BTW your title is a little confusing because the motor in your link is brushless not brushed.
If it is a screw jack , it should hold its position when the motor is not powered . If you think about it , when you manually operate such a jack , it stays put when you stop turning .
Have you measured or calculated the required torque to operate the jack? That's the first
piece of information needed. Then you combine that with the desired speed of operation
to determine the rpm and the motor power. Then you can select a gearmotor.
You'll need a couple of microswitches for limit detection.