en.Wedoany.com Reported - China's Taiyuan Heavy Industry Group (TZ) has completed a domestic retrofit of the frequency conversion drive system for a WK-20 mining electric shovel that has been in service for 20 years, with its self-developed dedicated frequency converter being applied to a mining electric shovel for the first time.
Located in a mining area in Inner Mongolia, this WK-20 electric shovel was manufactured by TZ and its mechanical performance remains stable. However, the original imported frequency conversion drive system has recently faced frequent failures, spare parts supply disruptions, and high maintenance costs, making it difficult to adapt to heavy-load and dusty working conditions. Given the high cost of replacing the equipment with a new one and the risks of continued use, TZ coordinated with the user to carry out a domestic retrofit, replacing the shovel's core drive system.
The difficulty of this retrofit lies in the adaptation and debugging. The debugging method of the frequency conversion drive system is completely different from traditional approaches, requiring solutions to issues such as load mutations during heavy-load excavation, coordinated actions during frequent direction changes, and the harsh environment of dusty and freezing mining areas. TZ's technical team tackled each step on-site, including hardware adaptation, algorithm matching, and system integration. After repeated testing and optimization, they ultimately achieved a perfect match between the frequency conversion drive system and the electric shovel.
The retrofitted electric shovel has improved performance, featuring low-speed high-torque output to ensure smooth and powerful hard rock excavation without stalling. The zero-speed hovering function allows the bucket to remain stable in the air, preventing the risk of bucket slippage. The energy recovery technology automatically converts potential energy into electrical energy during downhill or braking, achieving energy savings and consumption reduction. The frequency converter adopts a high protection level, a new generation of modular heat dissipation technology, and a high-strength cabinet structure design to cope with harsh conditions such as overload, overvoltage, dust, and moisture.
The electric shovel has been in operation for five months. Drivers report that it is easy to operate, responsive, and powerful during excavation. The user states that the frequency converter's operating temperature has significantly decreased under high-temperature summer conditions, reducing fault-related downtime. Additionally, the variety of spare parts has been reduced, lowering maintenance workload, and the increased overall equipment availability has led to production growth. A mine management official said, "All our electric shovels will gradually be equipped with domestic dedicated frequency converters. TZ is reliable!"
TZ stated that this WK-20 electric shovel retrofit marks the starting point for upgrades, with plans to continue focusing on the domestic retrofit of frequency conversion drive systems for mining electric shovels, promoting technological upgrades in mining equipment.
