Which Variable Frequency Drive (VFD) is Suitable for a Pump?
A variable frequency drive on a pump is a logical choice in almost any industrial installation. Which VFD is most suitable depends on three factors: the pump’s motor power, the supply voltage (230V or 400V, single- or three-phase) and whether you need pressure or flow control. For most pump applications, a VFD with integrated PID control is sufficient, so the pump automatically maintains constant pressure or flow.
As a rule of thumb: for simple pumps up to approximately 4 kW, the compact Fluxcon FLC150 is often sufficient. For larger pumps, water treatment installations and applications requiring precise pressure or flow control, sleep/wake functions and dry-run protection, the Fluxcon FLC500 is the better choice. The FLC500 is available from 0.75 kW to 400 kW, covering virtually every pump application.
Pumps are used in industrial installations to transport liquids, for example in process plants, cooling systems and water treatment. A pump is typically selected for a specific flow rate at a certain head. In traditional systems, flow is controlled using valves or throttling devices – which wastes energy. With a variable frequency drive, you control the pump speed directly, so the flow rate is precisely adjusted to process demand without energy losses caused by throttling. Within modern industrial automation, this control is a key element of efficient drive technology and reliable motor control.
Variable Frequency Drive for Pumps in Water Treatment
In water treatment and water purification, pumps often run continuously and under varying load. This is precisely where a VFD delivers the most value. The integrated PID controller in the Fluxcon series adjusts the speed based on a pressure or level signal, keeping system pressure constant regardless of demand. Additional functions make pump control more reliable:
- Sleep/wake function: the pump automatically switches to a low-energy mode at low demand and restarts as soon as pressure drops – saving additional energy.
- Dry-run protection: the integrated load monitor protects the pump against running dry.
- Pump alternation (cascade): with multiple pumps, the control alternates the load, extending service life.
- Water hammer prevention: linear starts and stops via the soft start function prevent pressure spikes that can damage the system.
Optimized Process Control with VFDs
By varying the motor frequency, pump flow can be easily adjusted to match real-time system demand. This ensures stable pressure and flow, enabling efficient pump operation. Proper VFD integration allows pumps to be connected to machine control, process automation and pressure control systems. More technical background on VFD operation can be found in the Fluxcon variable frequency drives wiki and in our VFD applications FAQ.
Energy Savings with VFDs on Pumps
A key advantage of using VFDs in pump applications is energy savings. By reducing pump speed when full capacity is not required, energy consumption can be significantly reduced. Depending on the application, energy savings of approximately 20% to 40% can be achieved. Since pumps often operate continuously, this can result in substantial cost savings.
Fluxcon also supplies VFDs suitable for modern permanent magnet synchronous motors. These motors offer very high efficiency and exceed current energy efficiency standards.
Would you like a calculation example for pump energy savings? Contact our specialists – we are happy to calculate it for your specific situation.
IE3 Efficiency Directive
Since January 1, 2015, the IE3 efficiency directive for electric motors has been in force. All motors from 0.75 kW up to and including 7.5 kW must meet IE2 efficiency requirements, and motors above 7.5 kW must comply with IE3 efficiency – or IE2 in combination with a variable frequency drive (VFD). A VFD on your pump therefore also helps you meet the statutory efficiency requirements.
Reduced Wear with VFD-Controlled Pumps
Lower operating speeds extend maintenance intervals. Without throttling valves, the pump operates more efficiently with reduced mechanical stress. This results in lower loads on bearings and reduced pressure on seals, leading to less wear and longer service life. Thanks to the soft start function, pressure spikes (water hammer) are eliminated, preventing system damage.
Improved Performance with VFDs on Pumps
Using a VFD prevents current peaks and maintains a high power factor (cos φ) in the electrical system. The integrated PID functionality in the Fluxcon FLC150 and FLC500 series allows constant pressure or flow control. This enables variable flow rates based on process demand, ensuring optimal pump performance with minimal energy consumption.
Fluxcon VFD Solutions
Fluxcon technical specialists work with you to analyze your processes and identify opportunities for optimization and energy savings. We support you in selecting, configuring and commissioning the right VFD for your pump – including more complex water and process installations. With the wide Fluxcon product range, you will always find the optimal solution.
Fluxcon is a high-tech company with multiple locations in the Netherlands and operates worldwide. We offer a broad range of energy-efficient drive and control solutions, including variable frequency drives, soft starters and control panels.
Fluxcon products are certified by international organizations and used in more than 100 countries. Fluxcon VFDs stand out due to advanced functionality, ease of use, competitive pricing, fast delivery from stock and expert technical support from experienced drive specialists.
