Which parameter governs the maximum permissible incline of lifts?

• A. Force Resistance
• B. Angle of Inclination
• C. Winding Drums
• D. Manual Unlocking

Answer: (B)

The limit on how steep a lift or escalator can safely operate is set by the angle of inclination. As the slope increases, the component of the car’s weight acting along the direction of travel (gravity) grows, which a drive system must overcome to move upward or must resist to hold in place. The drive train, braking, and safety systems are sized for a certain maximum tractive effort and stopping capability at a given load, so the steepness of the rise determines whether the system can reliably start, run, and stop safely. If the incline were increased beyond that limit, the motor may not be able to move the car, or the brakes may not be able to hold it securely, creating unsafe conditions.

The other options don’t set this limit. Force resistance isn’t a standard factor used to define slope limits; winding drums are part of how force is transmitted but don’t by themselves determine the maximum incline; manual unlocking is a safety feature for maintenance or emergency use, not a parameter that establishes the allowable incline.