Load Optimization of a Single-Sided Electromagnetic Elevator

Abstract

This study investigates load optimisation in an existing elevator system to evaluate variations in thrust relative to defined performance objectives—thrust and efficiency. Using the elevator’s actual design specifications, simulations were conducted to assess performance under varying load conditions. A user-driven iterative optimisation algorithm, termed the Wire Gauge Variation and Slot/Tooth Ratio (WGVSTR), was developed and implemented in MATLAB. The key advantage of the WGVSTR algorithm lies in its flexibility, allowing users to achieve desired optimisation goals by adjusting relevant design parameters. The analysis focuses on identifying the load condition that produces a thrust output closest to the target value while maintaining efficiency. The total weight of the elevator system without passengers is 1680 kg. Passenger loads, with each passenger assumed to weigh 75 kg, were incrementally added in eight steps up to 600 kg, exceeding the allowable limit of 375 kg (five passengers) for the existing model. Simulation results show that thrust and efficiency remained stable from Steps 1 to 5, corresponding to total loads of 1755 kg, 1830 kg, 1905 kg, 2055 kg, and 2130 kg. The 2055 kg load (Step 4), representing five passengers, was identified as the optimal load, yielding a full machine thrust of 26,560 N with minimal drop in output thrust. Beyond this point, thrust reduction became evident: 26,555 N, 26,530 N, and 24,500 N for Steps 6, 7, and 8, respectively. At Step 7 (2205 kg), equivalent to seven passengers, the thrust decrease was minimal (20 N below nominal), designating it as the maximum safe load. Efficiency remained constant up to Step 6 but dropped slightly to 87.28% and 87.25% at Steps 6 and 7, respectively, before declining sharply to 60.22% at Step 8 (2280 kg). The thrust and efficiency values at the maximum load were compared with those at no-load conditions to determine the elevator’s optimal and maximum allowable loading limits for safety and performance assurance.