December 1, 2015, by Parker Electromechanical Team
5 minute read.
Benefits of Using Variable Frequency Drives (VFDs) in Compressor Applications
Recent improvements in Variable Frequency Drives (VFDs) offer more than just energy savings, especially when paired with motor/compressor systems. Here are five reasons to consider using a VFD in your compressor application:
- Energy Efficiency The most obvious advantage of a VFD is notable energy efficiency. In a typical compressor setup, a direct electrical supply powers the motor, which runs the compressor at a continuous speed regardless of demand, wasting energy. With a VFD, the motor speed adjusts based on the application’s demands. When less power is needed, the drive slows the motor, eliminating energy wastage. Studies show a 20% reduction in motor speed can lead to a 50% energy saving (source: GAMBICA). Operators of compressor-based systems in industries such as refrigeration or pneumatic power supply can achieve energy efficiencies and cut costs using variable speed drives.
- Advanced Functionality VFDs now offer exceptional feedback and monitoring capabilities. Sensors detecting variables like pressure, temperature, or movement feed data into the drive control module, adjusting the motor speed to optimize output. For example, if temperature monitoring shows the motor is overheating, the VFD can lower the speed, send error signals, or stop the motor altogether. This adaptability improves application performance and allows additional variable monitoring.
- Reduced Component Degradation Optimizing motor and compressor performance reduces stress on mechanical and electrical components, limiting wear-related failures. By reducing motor speed at certain points, the system places less stress on components such as cables and connectors, extending their lifespan.
- System Reliability Many drives now include safety features like short circuit protection and Safety Torque Off (STO). Choosing a drive with these features reduces the need for additional electrical components like motor circuit breakers and contactors, cutting costs and increasing system reliability.
- Lower Starting Currents Compared to mains-powered motors with direct starting, a VFD can reduce the starting current by up to 80% without affecting starting torque. Lower starting currents reduce stress on the energy grid, minimizing the impact on other local energy consumers and reducing electrical equipment failures.
Conclusion
As VFD functionality becomes more advanced, manufacturers are simplifying usability and the commissioning process, making VFD benefits more accessible. Complex settings are largely eliminated, allowing manufacturers or mechanics to perform commissioning without special electrical knowledge. Simpler software tools and databases with pre-loaded information on motors, compressors, and other components make setup easier.
Considering the energy savings alone, a VFD typically pays for itself within eight months, eliminating investment risk. The combination of improved usability, cost savings, and performance benefits makes VFDs a valuable investment for powering compressors.
