Changsha Zoomlian Pump Co., Ltd. 长沙中联泵业股份有限公司

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    Technical Diagnosis and Solutions for Abnormal Speed Fluctuations in Mining Multistage Pumps

    Publication Date:

    2026-04-15

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    As the core equipment of mine drainage and conveying systems, the speed stability of multistage mining pumps directly affects pump unit operational efficiency and the continuity of mine production. Changsha Zoomlion Pump Industry Drawing on years of R&D experience in mining pumps, this paper analyzes the root causes of rotational speed instability and proposes technical solutions from four perspectives: electrical systems, mechanical design, fluid control, and system management.

     

    Mining multistage pump

     

    I. Common Fault Causes and Technical Analysis

    1. Power Supply System Fluctuations: The underground power supply network in mines is susceptible to voltage sags and harmonic distortion due to sudden load changes and cable aging. Field measurements show that a voltage deviation of ±5% can cause motor speed fluctuations exceeding 3%, and prolonged fluctuations can accelerate insulation degradation in motors.

    2. Transmission system defects: In belt drives, differences in V-belt pulley diameters and uneven belt tension can cause periodic fluctuations in rotational speed; misalignment of the coupling (radial deviation exceeding 0.1 mm/m) generates additional torque, leading to unstable pump shaft speed.

    3. Fluid-dynamic interference: When there is a sudden change in the valve opening, cavitation occurs in the pipeline, or the solid content of the fluid exceeds the allowable limit (>8%), the pump impeller experiences force imbalance, and a measured flow fluctuation of 15% can result in a speed deviation of ±20 rpm.

    4. Control system faults: Logical errors in the PLC program and improper parameter settings of the variable-frequency drive (e.g., imbalanced PID tuning coefficients Kp, Ki, and Kd) can lead to failure of closed-loop speed control, which is particularly evident in constant-pressure water supply systems.

     

    II. Technical Solutions from Changsha Zoomlion Pump Industry

    (1) Electrical System Optimization: Intelligent Voltage Regulation Module: This module employs a custom-designed isolation transformer and active filter combination supplied by Changsha Zhonglian Pump Industry, which effectively filters 50 Hz/60 Hz grid harmonics and keeps voltage fluctuations within ±1%. Field tests have confirmed its suitability for underground power supply systems operating at 660 V and 1140 V. Redundant Power Design: Critical pump units are equipped with a dual-circuit power switching device featuring a switching time of less than 50 ms, ensuring seamless dual-power source switching in mining operations without any interruption in pump speed.

    (2) Mechanical Drive Upgrade: Synchronous Belt Drive System: Employs imported polyurethane synchronous belts with an elongation of less than 0.5%, paired with pulley tooth profile machining accuracy (tooth profile error less than 0.02 mm), achieving speed fluctuation of less than ±1 rpm. High-Precision Coupling: Undergoes laser alignment calibration prior to shipment (accuracy up to 0.01 mm/m) and is accompanied by an ISO 10820 certification report.

    (3) Fluid Control Optimization: Dynamic Flow-Balancing Valve—A V-cone flowmeter and an intelligent valve assembly, both independently developed by Changsha Zhonglian Pump Industry, are installed at the pump inlet. The PLC continuously adjusts the valve opening in real time, ensuring that flow fluctuations remain within ±3%. Gas–Liquid Separation Device—For mines with high gas content, a cyclonic gas–liquid separator is employed, achieving a separation efficiency of over 95% and thereby preventing sudden speed drops caused by cavitation.

    (4) Intelligent Monitoring System Multi-parameter sensors: Integrated vibration (range 0–100 mm/s), temperature (-20°C to 150°C), and rotational speed (0–3,000 rpm) monitoring modules, with a data sampling frequency of 1 kHz, connected to the mine’s SCADA system via 4–20 mA signals. Remote diagnostic platform: Deployment of the Changsha Zoomlion Pump Industry Cloud Diagnostic System, which supports AI-based predictive maintenance and can provide early warnings—up to 72 hours in advance—of abnormal rotational speed trends.

    (5) Standardized Operations and Maintenance: Three-tier maintenance system—daily routine inspections, weekly inspections (bearing clearance < 0.2 mm), and monthly inspections (impeller dynamic balancing tests); key components are covered by a 12-month warranty.

     

    Through the aforementioned technical solution, Changsha Zoomlion Pump Industry has achieved over 99.9% rotational speed stability for its mining multistage pumps, with an average mean time between failures of 8,000 hours, thereby significantly reducing the operation and maintenance costs of mining equipment. The company’s technical personnel also provide free on-site vibration spectrum analysis and comprehensive system diagnostic reports.

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    Impact of Excessive Load on MDP-Type Wear-Resistant Self-Balancing Multistage Mine Pumps and Corresponding Countermeasures

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    Practical Procedures for Priming and Bleeding Air from a Wear-Resistant Multistage Centrifugal Pump Prior to Startup in Coal Mines (Specifically for Main Drainage Systems)

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