Our team built a cascading elevator similar to a greyt elevator and we’ve been having issues with the motor backdriving. Whenever we lift the elevator, after it lifts the weight of the carriage causes the elevator to fall back down. We’re driving it with a cim at about a 10/1 gear ratio. Any suggestions on how to prevent this backdriving?
This is not a surprising situation given your gear ratio. Most teams will use an encoder and some sort of PID control to make the elevator motor actively hold it’s position.
If your elevator is too heavy, it will require a significant amount of power to hold it’s position and end up heating up the motor to the point of failure. If that’s the case, you may want to consider since sort of spring to counterbalance the elevator. Or possibly a brake to hold it’s position without using the drive motor.
Actually, it’s not the worm gear that causes the window motors to not backdrive. The gearbox has locking pins on it that cause that behavior. You can remove those pins and have a window motor that can be backdriven.
Anyways, I second the disc brake. We stalled our motors on the past two elevators we built, with unhappy results. This year, we put on a disc brake and it’s pretty much the perfect solution. The elevator goes up and locks in position with no movement or sagging at all, and we got a set of two brakes for about $20 on Amazon. Insanely cheap!