Motor selection is critical for automatic sliding door performance and longevity. Undersized motors struggle with heavy doors and may fail prematurely, while oversized motors waste energy and create abrupt operation. This article explains motor selection criteria and thrust force calculation.
1. Door Weight and Inertia
The motor must overcome door panel weight, track friction, sealing forces, and wind loads to achieve smooth motion. Door panel weight typically ranges from 80-150 kg for standard commercial doors. The track system, typically aluminum with polymer bearings, introduces friction that the motor must overcome. Weather stripping and seals add resistance during closing that increases with seal compression.
2. Thrust Force Requirements
Calculate required thrust by multiplying door weight by a friction coefficient of 0.05-0.1 for well-maintained track systems. Add wind load estimates: 10-30 N per square meter of door area in moderate wind conditions, up to 100 N per square meter in exposed locations. A 100 kg door in moderate conditions requires approximately 100-150 N thrust force for normal operation, but must produce 2-3 times this force for reliable emergency backup operation and cold weather starting.
3. Motor Power Ratings
Commercial sliding door motors are rated from 60W to 250W depending on door size and application. Standard single-slide doors up to 120 kg typically use 100-120W motors. Heavy commercial doors up to 200 kg require 180-250W motors. Industrial sliding doors exceeding 200 kg may require custom motor solutions with gear reducers designed for high thrust applications.
4. Speed and Cycle Requirements
Opening speed requirements range from 300-700 mm per second depending on traffic volume and accessibility requirements. Higher speeds process more traffic but require more sophisticated control systems for smooth stopping. Motors rated for high cycle applications endure 200-300 daily cycles without thermal overload, while standard commercial ratings handle 100-150 daily cycles.
5. Voltage and Electrical Considerations
Most commercial sliding door motors operate on 220V single-phase AC power. Three-phase 380V motors are available for heavy industrial applications requiring higher power output. Verify that electrical supply capacity matches motor starting current requirements, which typically run 3-5 times normal operating current during acceleration periods.
This article compiles information from publicly available automatic door industry resources.