FGI FD5000 Series MVD used in Mine Main Drainage Pumps For Energy Saving

Project Overview

The mining industry consumes high energy, handles heavy loads, and runs continuously. Main drainage pumps play a key role in mine safety. They remove underground water, control water levels, and prevent tunnel flooding. These pumps account for over 35% of auxiliary energy use in mines.

Traditional fixed-speed operation uses outlet valves to control flow and head. This wastes a lot of energy, causes strong startup surges, leads to unstable water level control, increases equipment wear, raises maintenance costs, and creates safety risks. Mines urgently need MVD-based energy saving and intelligent control upgrades.

Customer Pain Points

1. High energy costs – Pumps are often oversized. They run at full speed (50Hz) while valves control the flow. Valves typically stay only 45–60% open. A large portion of energy turns into pressure loss and heat. Water inflow varies greatly between rainy and dry seasons. During low inflow periods, wasted energy exceeds 28%. Electricity costs remain very high.

2. Severe mechanical stress – Direct starting of high-voltage motors causes inrush current 5–7 times the rated current. This impacts the mine power grid, causes voltage drops, trips switches, and ages distribution equipment. Instant torque shocks lead to severe vibration in pump bearings, couplings, and pipes. Seal leaks and impeller wear happen frequently.

3. Poor control accuracy – Manual valve adjustment responds slowly, causing large water level fluctuations. This risks flooding, dry running, and cavitation, endangering underground operations. The system cannot automatically maintain a safe constant water level.

Custom VFD Solution

1. Precise selection and configuration

   Considering the mine environment – humid, dusty, explosive, and requiring 24/7 heavy-duty operation and the demands of PID closed-loop water level control and high torque at low frequencies. We selected the FGI FD5000-10/900F-1A four-quadrant medium-voltage drive

 with these features:  

   - Rated voltage: 10kV  

   - Rated power: 900kW  

   - Rated current: 65A  

   - Control modes: sensorless vector control, PID closed-loop automatic water level control  

   - Protection rating: IP54 – dustproof, moisture-proof, anti-interference  

   - Core functions: soft start/stop, high torque at low frequencies, multiple protections, Modbus communication, remote monitoring, fault warning

2. Technical advantages of the solution

   Energy-saving speed control： No more valve throttling. The VFD adjusts pump speed in real time based on underground water inflow. It pumps only as needed, eliminating all wasted energy.  

   Soft start protection： Limits startup current to within 1.5 times rated current. No grid shock, no mechanical hard impact. Vibration and noise drop significantly.  

   Constant water level control：The PID closed-loop system automatically keeps the underground water level within the set range. This prevents flooding and cavitation, enhancing drainage safety.  

   Better power quality：The multi-level series topology keeps input current THDi ≤ 4%. No extra harmonic filtering required. Power factor improves to above 0.96.  

   Adapts to harsh conditions：Withstands moisture, dust, and wide voltage variations, ensuring stable 24/7 operation in underground environments.

3. Implementation architecture

   We used a one-drive-one-motor automatic bypass control scheme. We kept the original fixed-speed circuit as an emergency backup. During maintenance or faults, the system switches seamlessly without stopping drainage. The VFD connects to the mine’s underground automation monitoring system, enabling remote start/stop, automatic water level regulation, data collection, and alarm notifications.

Full Implementation Process

Phase 1: Preliminary survey and design

Our technical team conducted multiple on-site surveys of underground hydrology and pump room layouts. We collected pump parameters, calculated energy baseline, and custom-designed electrical drawings and safety construction plans.

Phase 2: Installation and wiring

We installed the VFD in a container-type enclosure with moisture-proof and anti-corrosion sealing. We separated strong and weak current wiring, ensured proper grounding, and added dehumidifying and cooling devices inside the cabinet to strictly control temperature rise and condensation.

Phase 3: Commissioning and trial operation

Our engineers tuned the PID parameters for water level control. We performed no-load and loaded step-by-step debugging, then a continuous 72-hour full-load operation test. We locked in the optimal frequency range for the pumps to match safe drainage needs.

Phase 4: Acceptance and delivery

We organized joint acceptance by the customer’s equipment and production departments. We delivered a complete “Retrofit Technical File” and “Operation & Maintenance Manual”. We also provided two rounds of hands-on training for the customer’s operations team.

Measured Results After Retrofit

1. Energy saving data  

   Before: Average daily pump energy use – 16,800 kWh. Annual use – 6.13 million kWh.  

   After: Average daily pump energy use – 11,650 kWh. Annual use – 4.25 million kWh.  

   Key result: 30.7% total energy savings – Annual electricity cost reduction of 442,000 RMB. Payback period: approximately 1.2 years.

2. Better equipment operation

   Equipment failure rate dropped by 84%. Unplanned downtime decreased by 610 hours per year.  

   Pump vibration reduced by 66%. Service life of impellers, bearings, and seals extended significantly.

3. Lower maintenance costs  

   Annual spare parts cost decreased by 86%. Manual inspection and valve adjustment workload reduced by 60%.  

   Automatic and stable water level control greatly improved drainage safety, eliminating the risk of flooding.

On-Site Photos  

 FGI FD5000 series 10kV Medium-voltage drive control cabinet

Customer Feedback  

“After converting our main drainage pumps with MVD, we saw clear electricity savings. The pumps run smoother, make less noise, and require far fewer spare parts. Underground water level control is now fully automatic – no more manual valve adjustments. This greatly reduces safety risks. The FGI FD5000 runs reliably, and their technical service is professional. FGI is a trustworthy partner for mine energy-saving retrofits.”  

— Electromechanical Mine Director, Large Mining Group

This case shows how the FGI FD5000 medium-voltage VFD successfully solves major pain points for mine main drainage pumps – high energy use, heavy shocks, rough control, and serious safety risks. It delivers four key values: energy saving, safe and stable operation, lower costs and reduced wear, and intelligent automation.

If you need VFD retrofits for fans, pumps, air compressors, conveyors, or other industrial equipment, contact us for a free energy assessment, custom retrofit proposal, and on-site survey. We will build you an efficient, intelligent industrial automation system.