If a SwitchBot Curtain 3 on a U-rail repeatedly stops short, distinguish an endpoint setup problem from a curtain that physically catches before buying another motor.
Mark the intended open and closed positions
Check that the exact Curtain 3 variant matches your rail. With the motor not moving, inspect the travel path for a visible obstruction or snag. Note where the curtain stops and whether the same point is involved each time. Follow SwitchBot’s U-rail calibration guide for your device without forcing the mechanism.
Repeat the same full command
Try the same full open and full close commands after calibration. If the curtain now stops at the marked positions, recheck any routine that asks for partial travel. If it still catches at the same rail joint, focus on physical fit rather than repeatedly recalibrating or buying a second motor.
See the manufacturer’s guidance for current requirements. Related: smart curtain motor rail fit measurement.
