Abstract: The invention relates to a method for defining a tension of a belt of an automatic door. The method comprises: exciting a resonant frequency of the belt to cause a vibration of the belt, obtaining motion data representing motion of an electric motor configured to move the belt, defining vibration information representing the vibration of the belt based on the obtained motion data, and defining the tension of the belt based on the defined vibration in-formation and predefined characteristics of the belt. The invention relates also to a door drive unit and a computer program for defining a tension of a belt of an automatic door.

Abstract: The method includes loading and/or unloading the car, determining whether the car doors are fully closed or not fully open, measuring a total actual axial mass F?act hanging from the traction sheave, determining a stalling limit total minimum axial mass F?min, checking reopening of the car doors, whereby if the car doors are reopened, then return to beginning, else, continue, permitting starting of elevator, comparing the total actual axial mass with the stalling limit total minimum axial mass, whereby if the total actual axial mass is equal to or greater than the stalling limit total minimum axial mass, then permit normal run of the elevator car to the next landing, else, stop the elevator.

Abstract: A method includes calculating a motor torque estimate for an electric motor of an elevator in an elevator run, determining a difference between the calculated motor torque estimate and a realized motor torque during the elevator run, and generating a signal indicating possible brake dragging based on the difference between the motor torque estimate and the realized motor torque.

Abstract: The method includes loading and/or unloading the car, determining whether the car doors are fully closed or not fully open, measuring a total actual axial mass F?act hanging from the traction sheave, determining a stalling limit total minimum axial mass F?min, checking reopening of the car doors, whereby if the car doors are reopened, then return to beginning, else, continue, permitting starting of elevator, comparing the total actual axial mass with the stalling limit total minimum axial mass, whereby if the total actual axial mass is equal to or greater than the stalling limit total minimum axial mass, then permit normal run of the elevator car to the next landing, else, stop the elevator.

Abstract: There is provided displaying a user interface during a power outage. A touchscreen comprises a lower layer comprising an electronic paper display and an upper layer comprising a transparent display. The touch screen may be arranged in a frequency converter and a drive system.