Application of the Xindashida AS800 Series High-Voltage Inverter in a Belt Conveyor System at a Coal Mine (a Mine in Ordos)
2025-06-05
Application of the Xindashida AS800 Series High-Voltage Inverter in a Belt Conveyor System at a Coal Mine (a Mine in Ordos)
Project Background
The outbreak of the COVID-19 pandemic has caused significant disruptions to production and economic activities across various regions. The planned commissioning of three high-voltage variable-frequency drives for main shaft conveyor belts at a coal mine in Ordos, originally scheduled for February 15, has also been affected. If these drives cannot be put into operation promptly, it will impact heating demand in certain northern regions. Based on our understanding of the actual site conditions and considering the user-friendliness of New Shida’s products, we have adopted an alternative solution—remote commissioning—for this project. This approach has fully demonstrated the ease of use of New Shida’s variable-frequency drives.
Customer needs
The user wishes to expand production capacity and address the issue of uneven inverter output caused by the previous manual setting method, as well as the overvoltage alarms triggered when the slave unit is dragged into generator mode. Additionally, they aim to extend the service life of the belt.
Xinshida Solution
1. Condition of the main mine shaft belt system
Original System Configuration: Belt Conveyor Capacity: 1500 t/h; Belt Specifications: Width 1400 mm, Strength ST3150, Steel Cord Core; Belt Speed: 3.15 m/s; Conveying Length: 1110 m; Inclination Angle: +16°; Drive Power: 3 × 710 kW, Variable Frequency Drive; Main Motor Voltage: 6000 V. Upgraded and Modified Section: The drive power has been increased from the original 3 × 710 kW to 3 × 1000 kW. The focus of this upgrade is to expand production capacity, with the motor and variable frequency drive system being upgraded accordingly. The upgraded belt conveyor capacity is expected to reach 2000 t/h.
2. On-site control plan confirmation
● Original system conditions
The original system at this coal mine site also used high-voltage variable-frequency drives for propulsion. However, as production capacity increased, the original system could no longer meet the demands of production and transportation. The original system employed a separate control approach: three variable-frequency drives each received individual set-point signals, and torque balance was achieved by manually adjusting the operating frequencies.
● Renovation objectives
The new-time frequency converter employs a master-slave control droop function. The software automatically calculates the output torque and achieves automatic power balancing, ensuring that the output voltage and current of the slave unit are consistent with those of the master unit. This truly realizes automatic load balancing for the frequency converter. The system control scheme is shown in Figure 1 below.
Figure 1—Master-Slave Control System Diagram
3. Guide on-site wiring.
• Internal wiring of the inverter
The work primarily involved connecting the communication cables inside the inverter. With remote guidance, we quickly completed the setup of the communication system required for commissioning. The internal communication connection diagram for the inverter is shown in Figure 2.
• External control wiring connection. Extract the control signals required by the user from the drawings, list the signals along with their corresponding wire numbers and terminal numbers based on signal type. Use WeChat video instructions to guide the user in completing the control wiring according to Table 1.
Figure 2—Internal Communication Connection of the Inverter
Table 1—External Control Wiring for the Inverter
4. No-load trial run
● High-voltage side wiring inspection. Before the trial run, provide users with WeChat video guidance to confirm and check the wiring connections for the inverter’s incoming and outgoing lines.
● Check of inverter parameter settings. Most of the inverter parameters have already been fixed, and the master-slave control parameters have also been embedded into the multi-drive module, making the inspection process relatively smooth.
● Confirmation of control logic
● Operating mode: After the operator console sends start/stop commands to the host, while the host executes the start/stop operation, it also controls the start/stop of Slave Unit 1 and Slave Unit 2 via internal communication.
● Fault Handling Method: If any one of the three frequency converters reports a fault and shuts down, the three frequency converters will perform internal communication to determine the fault and simultaneously initiate an emergency stop and lockout.
● Emergency stop procedure: If any one of the three variable-frequency drives is manually emergency-stopped, the three drives will perform an internal communication-based emergency-stop check and simultaneously execute an emergency-stop lockout.
● Issues Encountered During No-Load Trial Operation and Their Solutions
Host failure: During the first high-voltage energization of the host, an optical fiber fault was reported on all power units' upstream links. Upon inspection, it was found that the fiber connectors on the master control side had been inserted backward for both upstream and downstream communications. After correcting the issue, the problem was resolved.
Slave Unit 1 Failure: During master-slave control interlock, Slave Unit 1 reported a unit blocking fault. After inspecting the communication cable inside the frequency converter and replacing it with a shielded cable, and adding proper grounding measures, the issue was resolved.
Inverter Multi-Machine Drive Parameter Module
Inverter Parameter Setting Interface
5. Load testing and trial operation
Users can perform pre-production loaded tests using coal materials partially produced from underground stockpiles. After directly sending a start command to the host device from the user console, three variable-frequency drives will smoothly and gradually start driving the main shaft conveyor, transporting the coal materials produced underground to the unloading area. The loaded test run was successfully completed.
User Conveyor Belt Control Console
Inverter host operation interface
Associated products
AS800 High-Voltage Frequency Converter
Project Results
Coal is a fundamental resource essential for ensuring people's livelihoods. During the challenging period of the pandemic, this coal mine promptly resumed production in response to the nation’s call, and the frequency converters have now been officially put into operation.
In this application of the Xindashida high-voltage variable-frequency drive with constant-torque output, automatic load balancing has been achieved. According to feedback from the user’s site, under the previous manual setting method, the VFD output was uneven, often causing the follower unit to be dragged into generator mode, resulting in overvoltage alarms. After 1–2 years of use, the belt would stretch and become unusable due to uneven stress distribution. Following the retrofit, automatic load balancing has been implemented, significantly extending the belt’s service life and eliminating the risk of the follower unit’s overvoltage burning out the braking unit.
In addition, the successful implementation of this WeChat video-based guidance and commissioning has demonstrated the user-friendliness of the Xinshida high-voltage variable frequency drives. Currently, some of the factory-delivered VFD units have already achieved commissioning-free operation. In the future, Xinshida high-voltage VFDs will enable features such as online network-based commissioning and real-time fault diagnosis, thereby driving the intelligent transformation of the industrial control industry and opening a new chapter for remote services in special circumstances.
The inverter is operating normally.
Inverter host operation interface
