FGI FD5000 Series MVD used in Cement Kiln Exhaust Fan for Energy Saving

Project Overview

Cement production is a key area of high energy consumption. The kiln exhaust fan is a critical heavy-load device in the production line. It plays a key role in stabilizing negative pressure inside the kiln, transports exhaust gas, and supports material heat exchange. The fan's power consumption accounts for more than 35% of the total auxiliary equipment energy use in the plant.

Traditional fixed-frequency operation uses a damper to control airflow. This leads to widespread problems such as high energy waste, strong mechanical stress, poor process control, and high maintenance costs.

I. Core Pain Points at the at Customer Site

1.1 High Energy Costs

The fan design leaves excessive capacity margin. It runs at full 50Hz speed. A damper controls airflow, but its opening only 45%-60%. This results in significant electrical energy being lost

 as mechanical and heat loss. Under low load conditions, energy waste exceeds 28%, resulting in persistently high monthly electricity bills

1.2 Severe Mechanical Impact

Direct online starting of the high-voltage motor draws 5 to 7 times the rated current. This surge impacts the plant power grid, often causing transformer overload and switchgear overheating trips. Instant torque shocks loosen or crack fan bearings, couplings, and bases. Blade vibration and wear become severe.

1.3 Poor Process Control Precision

Manual damper adjustment introduces time lag. Kiln negative pressure fluctuates up to ±200Pa. This creates unstable kiln temperatures and affects clinker burning quality. Frequent abnormal stops interrupt continuous production.

II. Customized MVD Solution

2.1 Precise Selection and Configuration

Considering the cement plant’s high temperature, high dust, and 24/7 heavy load conditions, along with closed-loop negative pressure control and high torque at low frequencies, we selected the **FGI FD5000-10/800F-1A Medium voltage drive. Key specifications are as follows:

Rated voltage: 10kV

Rated power: 800kW

Rated current: 58A

Control modes: Sensorless vector control, PID negative pressure closed-loop control

Protection rating: IP54 (dust-resistant, high-temperature resistant, protects against workshop dust ingress)

Key features: High torque at low frequencies, soft start and soft stop, multiple electrical protections, Modbus industrial communication, remote fault warning

2.2 Technical Advantages of the Solution

Energy saving speed control: Eliminates damper throttling. The MVD adjusts fan speed based on kiln negative pressure and production load, replacing fixed-speed operation. It matches airflow to actual demand and eliminates unnecessary energy loss.

Soft start protection:Limits the start current to within 1.5 times rated current. No grid surge or mechanical torque shock. Fan vibration decreases significantly.

Process stability:Negative pressure PID closed-loop control keeps kiln negative pressure fluctuation within ±30Pa. Kiln temperature and process conditions stabilize, and clinker quality improves.

Power grid quality improvement: Unit series multi-level topology, input current harmonic distortion rate THDi ≤ 4%, no additional harmonic treatment equipment required, power factor of the power grid increased to above 0.96.

Suitable for harsh conditions:Wide voltage tolerance, dust-resistant, and anti-interference design, enables reliable 24/7 operation in high-temperature, high-dust cement plant environments.

2.3 Implementation Architecture

We used a one-drive-to-one-motor automatic bypass solution. The system keeps the original fixed-frequency circuit as emergency backup. Operators can manually switch during maintenance or fault conditions without stopping production. The MVD connects to the plant DCS via industrial communication bus, enabling remote start/stop, speed fine-tuning, automatic negative pressure control, real-time data logging, and remote fault alarms.

III. Full Implementation Process

3.1 Site Survey and Design

Our technical team visited the site three times. We conducted a deep survey of the site layout, collected equipment operating data, calculated energy consumption, prepared detailed electrical drawings, held technical clarifications, and planned shutdown windows.

3.2 Installation and Wiring

We installed the MVD inside a dedicated container, completed grounding, and separated high and low voltage cabling. We added cooling devices inside the cabinet to keep temperature rise within standard limits.

3.3 Commissioning and Trial Run

Our engineers precisely tuned PID parameters. We performed no-load and loaded trial runs, followed by a continuous 72-hour full load test. After commissioning, the fan operates stably at 42-45Hz, perfectly matching production process requirements.

3.4 Acceptance and Delivery

We organized joint acceptance with 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 operation and maintenance team.

IV. Measured Results After Retrofit (Key Highlights)

4.1 Energy Saving Data

Before retrofit: Average daily fan energy consumption 15,860 kWh, annual consumption 5.78 million kWh

After retrofit: Average daily fan energy consumption 11,230 kWh, annual consumption 4.10 million kWh

Key results: Total energy saving rate 29.8%, annual electricity cost savings $426,000 (at ~$0.10/kWh), payback period approximately 1.3 years

4.2 Equipment Operation Improvements

Equipment failure rate dropped 82%

Annual downtime reduced by 580 hours

Fan vibration decreased 65%

Significantly less wear on bearings, blades, and couplings

4.3 Lower Maintenance Costs

Annual spare parts and maintenance costs reduced 85%

Manual inspection frequency reduced 60%

Maintenance work efficiency increased 55%

Stable kiln negative pressure improved clinker passing rate by 2.3%, further raising production line capacity utilization

V. Site Photos

Before retrofit: Fixed-frequency damper control cabinet for cement kiln exhaust fan

(Image: Cement production line fan damper control site)

After retrofit: FGI FD5000 series 10kV Medium voltage drive in container

(Image: 800kW MVD container)

VI. Customer Endorsement

"The MVD retrofit for our kiln exhaust fan exceeded our expectations. The monthly electricity savings are very significant. Fan noise and vibration dropped significantly. The frequency of bearing spare parts replacement has been greatly reduced.Kiln negative pressure stays very stable, making clinker quality more consistent. The FGI FD5000 MVD runs reliably. FGI's technical team did professional installation and commissioning, and their after-sales service responds quickly. FGI is a long-term partner we trust for energy saving retrofits."

— Equipment Production Director, Major International Cement Group

VII. Summary and Contact

This case demonstrates how precise application of the FGI FD5000 series MVD successfully solved high energy consumption and high maintenance problems for a cement plant kiln exhaust fan. The solution delivers three key benefits: energy savings, improved quality and efficiency, and lower costs.

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