Abstract
Traditional vertical shaft drilling rigs often suffer from inconsistent speed regulation, high energy consumption, and excessive noise. To address these challenges, this work proposes a frequency conversion control scheme and validates its feasibility through theoretical analysis and experimental testing. The retrofit employs a variable frequency drive to enable stepless speed adjustment, allowing dynamic control of the motor input frequency and voltage. This results in continuously variable speed regulation, significantly enhancing the drilling efficiency and adaptability to diverse geological conditions. By optimizing load characteristics, the system achieves substantial energy savings, with field tests demonstrating over 35% reduction in electricity usage compared with the original model. For an annual operation of 10 months, this translates to estimated savings of 62,742 kWh. Additionally, the average noise level of the retrofitted motor decreases from 94.28 to 89.51 dB, falling below the 90 dB occupational noise exposure limit. The upgraded electronic control system also incorporates multiple safety features, including overcurrent and overvoltage protection, reducing operational risks. These test-verified results of the inverter-based retrofit demonstrate its potential to advance traditional drilling rigs toward greater efficiency, intelligence, and sustainability, offering valuable technical insights for modernizing geological drilling equipment.