EN 
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RU Where are frequency converters used: a complete guide to industries and applications
A frequency converter (VFD — Variable Frequency Drive) is an electronic device that changes the frequency and voltage supplied to an electric motor, enabling smooth speed control. Instead of running at a single fixed speed, a VFD allows you to precisely match motor speed to the actual load. The result is energy savings of 30–60%, extended equipment life, and full process automation.
In this article, we provide a detailed overview of the main application areas for frequency converters, show where they deliver the greatest benefits, and present a comparison table across industries.
Water supply and wastewater systems
Pumping stations are one of the most common installations for frequency converters. In water supply systems, network pressure constantly fluctuates depending on consumption. Without a VFD, the pump runs at full speed, and excess pressure is dissipated through throttle valves or bypass lines. This causes significant energy losses and water hammer effects.
A frequency converter solves this problem by automatically adjusting pump speed to match current demand. A pressure sensor sends a signal to the VFD, which instantly corrects the motor speed. A detailed guide on connecting a pressure sensor to a VFD is available in our article Setting up frequency converters with a pressure sensor.
Benefits of VFD in pumping systems:
- Energy savings of 25–50% by reducing speed during low-demand periods
- Elimination of water hammer — soft start and stop prevent pressure surges
- Reduced wear on pipes, valves, and fittings
- Stable pressure regardless of the number of consumers
- Automatic pump alternation in multi-pump systems
Ventilation, air conditioning, and heating (HVAC)
Building HVAC systems consume up to 40% of total electrical energy in industrial facilities. Fan systems, like pumps, often operate under variable load: minimal airflow is needed in the morning, maximum during peak hours.
A frequency converter for ventilation adjusts fan speed based on CO2, temperature, or humidity sensor readings. Fan power follows the cube law of rotational speed — meaning a mere 20% speed reduction cuts energy consumption by 50%. We cover this topic in detail in our article on frequency converters for energy-efficient ventilation.
In heating systems, VFDs control circulation pumps to maintain the set coolant temperature. This is critical for modern energy-efficient buildings where every kilowatt counts.
Compressor equipment
Compressors are among the largest energy consumers in any facility. The traditional operating scheme — start-stop cycling or throttle-based pressure relief — is extremely inefficient. Frequent starts wear out the motor, while throttle regulation wastes energy.
A VFD smoothly adjusts compressor output to match actual compressed air demand. Energy savings can reach 35–50%. A practical compressor modernization example is described in our article Setting up a VFD for compressor operation.
Additional benefits:
- Stable compressed air pressure with ±0.1 bar accuracy
- Reduced noise levels — the compressor does not constantly run at maximum
- Fewer starts and stops — extending motor and mechanical component life
- Integration into SCADA systems via Modbus/Profibus
Material handling: cranes, lifts, and conveyors
In crane applications, a frequency converter performs several critical functions: smooth starting and braking, precise load positioning, and overload protection. Without a VFD, the crane motor starts with a jerk, creating dynamic loads on the steel structure and cables. A VFD eliminates these issues by providing smooth acceleration and deceleration.
A practical application example is the VEICHI AC310 frequency converter for crane operation, which describes hoist mechanism setup with regenerative braking.
On conveyor lines, VFDs synchronize belt speed with the throughput of upstream and downstream production stages. In elevator systems, a VFD provides comfortable cabin acceleration and braking, as well as precise floor-level stopping.
Industrial manufacturing
In general industrial applications, frequency converters address a wide range of tasks:
- Winding equipment — cable, paper, film, and textile production. VFDs maintain constant material tension by automatically increasing speed as the roll diameter decreases.
- Extruders and mixers — precise screw speed control to maintain consistent product quality.
- CNC machines — spindle speed adjustment for different materials and tools.
- Centrifuges and separators — smooth acceleration to operating speed without grid overload.
- Packaging lines — synchronization of belt speed, dosing unit, and packaging machine.
Agriculture and food processing
In agriculture, frequency converters are used to control irrigation system pumps, livestock facility ventilation fans, and grain dryer systems. Speed regulation allows equipment operation to adapt to current conditions — temperature, humidity, and water demand.
In food processing, VFDs control mixers, dough kneading machines, pumps for liquid products (milk, juice, oil), and packaging line conveyors. The hygienic requirements of this industry demand smooth, vibration-free operation, and frequency converters are ideally suited for these tasks.
Mining and oil & gas industry
In mining, frequency converters control crushers, conveyors, mine ventilation fans, and dewatering pumps. Loads in these systems vary widely — from idle running to peak values when large rock pieces are fed into the equipment. VFDs protect the motor from overload and ensure stable operation.
In the oil and gas industry, frequency converters are used on drilling rigs, oil pumps, and gas pipeline compressor stations. Reliability and the ability to operate in hazardous areas are particularly important here — VFDs in protective enclosures with IP54/IP55 protection ratings are used for these applications.
Comparison table: VFD applications by industry
| Industry | Typical equipment | Energy savings | Primary benefit |
|---|---|---|---|
| Water supply | Pumps, booster stations | 25–50% | Stable pressure, no water hammer |
| HVAC | Fans, circulation pumps | 30–60% | Comfortable climate, reduced noise |
| Compressor stations | Screw and piston compressors | 35–50% | Stable pressure, fewer starts |
| Material handling | Cranes, lifts, conveyors | 15–30% | Soft start, precise positioning |
| Manufacturing | Extruders, CNC machines, mixers | 20–40% | Product quality, process flexibility |
| Agriculture | Irrigation pumps, dryers | 20–45% | Condition-based control, automation |
| Mining | Crushers, mine fans | 15–35% | Overload protection, reliability |
| Oil & gas | Drilling rigs, pumps, compressors | 20–40% | Explosion protection, continuous operation |
VFD vs soft starter: when to choose which
A common question is whether a full frequency converter is needed, or if a soft starter would suffice. The answer depends on the application:
- Frequency converter is needed when continuous speed control is required — pumps with variable load, fans with airflow regulation, conveyors with variable belt speed.
- Soft starter is sufficient when equipment runs at a single speed and you only need to limit inrush current — for example, for high-power pumps and compressors with constant load.
A VFD costs more than a soft starter but pays for itself much faster through energy savings. For applications with variable load, a frequency converter is the only correct choice.
How to select a frequency converter for your application
When choosing a VFD for a specific task, consider the following factors:
- Motor power — select the VFD based on the motor rated current with a 10–15% margin.
- Load type — fan/pump type (quadratic torque-speed relationship) or constant torque (hoists, conveyors).
- Supply voltage — single-phase 220 V or three-phase 380 V.
- Control method — scalar (V/f) for simple applications or vector control for precise positioning.
- Protection rating — IP20 for clean indoor environments, IP54/IP55 for industrial and outdoor conditions.
- Communication protocols — Modbus, Profibus, CANopen for integration into automation systems.
Our frequency converter catalog features solutions from leading global manufacturers: Schneider Electric, Siemens, ABB, Danfoss, Delta Electronics, INVT, Veichi, and others. For every application — from a small 0.75 kW pump to a 500 kW industrial drive — we will help you find the optimal solution.
Conclusion
Frequency converter applications span virtually every industry that uses electric motors with variable loads. From water supply and HVAC to mining — VFDs deliver energy savings, extend equipment life, and enable full process automation. Given the rising electricity tariffs in Ukraine, a VFD investment typically pays for itself within 6–18 months.
